2020-10-23T10:09:02Zhttp://edoc.mpg.de/ac_p_oai.ploai:edoc.mpg.de:269202003-08-0737:452
InBook
Statistical Theory of Nuclear Reactions
English
Academic Press
San Diego, Calif. [u.a.]
2002
1393
1413
Scattering: scattering and inverse scattering in pure and applied science
E. R. Pike
expertsonly
published
notspecified
H. A.
Weidenmüller
H. A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:04:07.705935
oai:edoc.mpg.de:269282003-08-0737:452
InBook
Unordnung und Chaos in Quantensystemen
German
Soc.
Halle
2002
343
355
47
Jahrbuch 2001 der Deutschen Akademie der Naturforscher Leopoldina (Halle/Saale)
Deutschen Akademie der Naturforscher Leopoldina (Halle/Saale)
LEOPOLDINA
expertsonly
published
notspecified
H. A.
Weidenmüller
H. A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:03:22.740164
oai:edoc.mpg.de:269332003-07-3037:452
InBook
Georg Christoph Lichtenberg
German
Margot-und-Friedrich-Becke-Stiftung
Heidelberg
2002
51
66
Die Vermehrung des Wissens und die Ausbreitung der Dummheit: zwei Vorträge gehalten im Rahmen der Margot-und-Friedrich-Becke-Stiftung am 5. Mai 2001 in Heidelberg ...
Zimmermann, Hans-Joachim, Brix, Peter
popular
published
notspecified
P.
Brix
Peter
MPI für Kernphysik
Guest Groups and Emeriti
2003
2003-07-30 11:11:52.090236
oai:edoc.mpg.de:277102003-08-0737:452
Article
Spreading widths for superdeformed states in Hg-194 and Pb-194
English
2001-12
064316
064316
064316
Physical Review C
Phys. Rev. C
6
6406
Using several theoretical models, we have obtained estimates for the spreading widths Gamma (!) for the decay out of a superdeformed (SD) band. We pay particular attention to the statistical model by Gu and Weidenmuller. Our results for Hg- 194 and Pb-194 are compared to other theoretical predictions and to experimental upperbounds for Gamma (!). We find that the models of Gu and Weidenmuller and of Vigezzi et al. yield a consistent description of the data. We relate Gamma (!) to the strength v of the interaction that couples the normally deformed levels to the SD level at which the decay out of the SD band occurs. Using an exponential spin dependence of v, we are able to reproduce the intraband intensities in the SD bands in Hg-194 and Pb-194.
expertsonly
published
joureview
R.
Krucken
R.
A.
Dewald
A.
P.
von Brentano
P.
H. A.
Weidenmüller
H. A.
000172733000024
0556-2813
Yale Univ, Dept Phys, AW Wright Nucl Struct Lab, New Haven, CT; 06520 USA; Yale Univ, Dept Phys, AW Wright Nucl Struct Lab, New Haven, CT 06520 USA; Univ Cologne, Inst Kernphys, D-50937 Cologne
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003-08-07 14:02:40.141784
oai:edoc.mpg.de:277142009-09-0337:452
Article
Partition functions in statistical mechanics, symmetric functions, and group representations
English
2001-12
066105
Physical Review E
Phys. Rev. E
6
6406
Partition functions for noninteracting particles are known to be symmetric functions. It is shown that powerful group- theoretical techniques can be used not only to derive these relationships, but also to significantly simplify calculation of the partition functions for particles that carry internal quantum numbers. The partition function is shown to be a sum of one or more group characters. The utility of character expansions in calculating the partition functions is explored. Several examples are given to illustrate these techniques.
expertsonly
published
joureview
A. B.
Balantekin
A. B.
Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA; Univ Wisconsin, Dept Phys, Madison, WI 53706 USA
MPI für Kernphysik
Guest Groups and Emeriti
2009-09-03 10:24:43.739183
oai:edoc.mpg.de:277232003-08-0737:452
Article
Spreading widths for superdeformed states in Hg-194 and Pb-194
English
2001-12
064316
064316
064316
Physical Review C
Phys. Rev. C
6
6406
Using several theoretical models, we have obtained estimates for the spreading widths Gamma (!) for the decay out of a superdeformed (SD) band. We pay particular attention to the statistical model by Gu and Weidenmuller. Our results for Hg- 194 and Pb-194 are compared to other theoretical predictions and to experimental upperbounds for Gamma (!). We find that the models of Gu and Weidenmuller and of Vigezzi et al. yield a consistent description of the data. We relate Gamma (!) to the strength v of the interaction that couples the normally deformed levels to the SD level at which the decay out of the SD band occurs. Using an exponential spin dependence of v, we are able to reproduce the intraband intensities in the SD bands in Hg-194 and Pb-194.
expertsonly
published
joureview
R.
Krucken
R.
A.
Dewald
A.
P.
von Brentano
P.
H. A.
Weidenmüller
H. A.
Yale Univ, Dept Phys, AW Wright Nucl Struct Lab, New Haven, CT 06520 USA; Univ Cologne, Inst Kernphys, D-50937 Cologne
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003-08-07 14:01:47.014902
oai:edoc.mpg.de:277982003-08-0737:452
Article
Stochastic properties of many-body systems
English
2001-12-15
302
309
Physica A
Physica A
1-4
302
The k-body embedded ensembles of random matrices originally defined by Mon and French are investigated as paradigmatic models of stochasticity in Fermionic many-body systems. In these ensembles, m Fermions in I degenerate single-particle states, interact via a random k-body interaction which obeys unitary or orthogonal symmetry. We focus attention on the spectral properties of these ensembles. We always take the limit l --> infinity. For 2k > m, the spectral properties of the k-body embedded unitary and orthogonal ensembles coincide with those of the canonical Gaussian unitary and orthogonal random-matrix ensemble, respectively. For k < < in < < l, the spectral fluctuations become Poissonian. The reason for this behavior is displayed by constructing limiting ensembles. The case of embedded Bosonic ensembles (m Bosons in l degenerate single-particle states interact via a random k-body interaction which obeys unitary or orthogonal symmetry) is also considered and compared with the case of Fermions. (C) 2001 Elsevier Science B.V. All rights reserved.
random-matrix theory; shell model; spectral statistics
expertsonly
published
joureview
H. A.
Weidenmüller
H. A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003-08-07 14:00:57.743429
oai:edoc.mpg.de:278012003-08-0737:452
Article
Wilson loops in N = 4 supersymmetric Yang-Mills theory from random matrix theory
English
2002-01-10
400
400
Physics Letters B
Phys. Lett. B
3-4
524
expertsonly
published
notspecified
G.
Akemann
G.
P. H.
Damgaard
P. H.
000173269200023
0370-2693
CEA Saclay, Serv Phys Theor, F-91191 Gif Sur Yvette, France; CERN, Div Theory, CH-1211 Geneva, Switzerland
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:57:43.559111
oai:edoc.mpg.de:278172003-08-0737:452
Article
Nonadiabatic controlled-NOT gate for the Kane solid-state quantum computer
English
2002-03
032303
032303
032303
Physical Review A
Phys. Rev. A
3
65
The method of iterated resolvents is used to obtain an effective Hamiltonian for neighboring qubits in the Kane solid- state quantum computer. In contrast to the adiabatic gate processes inherent in the Kane proposal we show that free evolution of the qubit-qubit system, as generated by this effective Hamiltonian, combined with single-qubit operations, is sufficient to produce a controlled-NOT gate. Thus the usual set of universal gates can be obtained on the Kane quantum computer without the need for adiabatic switching of the controllable parameters as prescribed by Kane [Nature (London) 393, 133 (1998)]. Both the fidelity and the gate time of this nonadiabatic controlled-NOT gate are determined by numerical simulation.
expertsonly
published
joureview
C.
Wellard
C.
L. C. L.
Hollenberg
L. C. L.
H. C.
Pauli
H. C.
000174548500045
1050-2947
Univ Melbourne, Sch Phys, Melbourne, Vic 3010, Australia;
MPI für Kernphysik
Group D. Schwalm
2003
2003-08-07 14:56:29.746411
oai:edoc.mpg.de:278242003-08-0737:452
Article
Modeling the reversible decoherence of mesoscopic superpositions in dissipative environments
English
2002-04
044101
Physical Review A
Phys. Rev. A
4
65
A model is presented to describe the recently proposed experiment [J. Raimond, M. Brune, and S. Haroche, Phys. Rev. Lett 79, 1964 (1997)] in which a mesoscopic superposition of radiation states is prepared in a high-Q cavity that is coupled to a similar resonator. The dynamical coherence loss of such a state in the absence of dissipation is reversible and can be observed in principle. We show how this picture is modified due to the presence of the environmental couplings. Analytical expressions for the experimental conditional probabilities and the linear entropy are given. We conclude that the phenomenon can still be observed provided the ratio between the damping constant and the intercavities coupling does not exceed about a few percent. This observation is favored for superpositions of states with a large overlap.
expertsonly
published
joureview
S. G.
Mokarzel
S. G.
A. N.
Salgueiro
A. N.
M. C.
Nemes
M. C.
Univ Sao Paulo, Inst Fis, Dept Fis Matemat, BR-05315970 Sao Paulo, Brazil; Univ Fed Minas Gerais, ICEX, Dept Fis, BR-30161970 Belo Horizonte, MG, Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:55:09.758997
oai:edoc.mpg.de:278302003-08-0737:452
Article
Rate equations for sympathetic cooling of trapped bosons or fermions
English
2002-04
043601
Physical Review A
Phys. Rev. A
4
65
We derive two different sets of rate equations for sympathetic cooling of harmonically trapped bosons or fermions. The rate equations are obtained from a master equation derived earlier by Lewenstein et al. [Phys. Rev. A 51, 4617 (1995)] by means of decoherence and ergodicity arguments. We show analytically that the thermal equilibrium state is a stationary solution of our rate equation. We present analytical results for the rate coefficients which are needed to solve the rate equations, and we give approximate formulas that permit their computation in practice. We solve the two sets of rate equations numerically and compare the results. The cooling times obtained in both approaches agree very well. The equilibration rates show fair agreement.
expertsonly
published
joureview
T.
Papenbrock
T.
A. N.
Salgueiro
A. N.
H. A.
Weidenmüller
H. A.
Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831, USA
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:53:29.382171
oai:edoc.mpg.de:281862003-08-0737:452
Article
Recursive construction for a class of radial functions. II. Superspace
English
2002-05
2741
2769
Journal of Mathematical Physics
J. Math. Phys.
5
43
We extend the recursion formula for matrix Bessel functions, which we obtained previously, to superspace. It is sufficient to do this for the unitary orthosymplectic supergroup. By direct computations, we show that fairly explicit results can be obtained, at least up to dimension 8x8 for the supermatrices. Since we introduce a new technique, we discuss various of its aspects in some detail. (C) 2002 American Institute of Physics.
expertsonly
published
joureview
T.
Guhr
T.
H.
Kohler
H.
000175145100038
0022-2488
Lund Univ, LTH, S-22100 Lund, Sweden; Univ Autonoma Madrid, Dept Fis, Madrid, Spain
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:40:44.133727
oai:edoc.mpg.de:281902003-08-0737:452
Article
Correlations of Wilson lines and the proton structure function F-2
English
2002-04
313
317
Nuclear Physics B-Proceedings Supplements
Nucl. Phys. B-Proc. Suppl.
108
We discuss deep inelastic scattering at low x as a critical phenomenon in 2 + 1 space - time dimensions. QCD (SU2) near the light cone becomes a critical theory in the limit of x --> 0 with a correlation mass m(x) proportional to x(v/2). We conjecture that the perturbative dipole wave function of the virtual photon in the region 1/Q < x(perpendicular to) < 1/m obeys correlation scaling Psi proportional to (x(perpendicular to))(-(1+n)) before exponentially decaying for distances larger than the inverse correlation mass. Using this behavior combined with an x-independent dipole proton cross section we calculate the proton structure function and compare with the experimental data.
expertsonly
published
joureview
H. J.
Pirner
H. J.
F.
Yuan
F.
000175246400056
0920-5632
Univ Heidelberg, Inst Theoret Phys, D-6900 Heidelberg, Germany
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:39:04.589826
oai:edoc.mpg.de:281912003-07-1137:452
Article
On the effective Hamiltonian for QCD: An overview and status report
English
2002-04
273
280
Nuclear Physics B-Proceedings Supplements
Nucl. Phys. B-Proc. Suppl.
108
The session on effective Hamiltonians and chiral dynamics is overviewed, combined with a review on the bound-state problem. The progress during this session allows to remove all dependence on regularization in an effective interaction, and to solve front form as if they were instant-form equations, with all the advantages implied.
expertsonly
published
joureview
H. C.
Pauli
H. C.
000175246400048
0920-5632
MPI für Kernphysik
Group D. Schwalm
2003
2003-07-11 14:34:13.97818
oai:edoc.mpg.de:281922003-08-0737:452
Article
On helicity and spin on the light cone
English
2002-04
251
255
Nuclear Physics B-Proceedings Supplements
Nucl. Phys. B-Proc. Suppl.
108
Starting from a one-body front-form equation with Lepage- Brodsky spinors we show, with a fair amount of new technology, how an integral equation in standard momentum space with Bjorken-Drell spinors can be obtained. The integral equation decouples for singlets and triplets.
expertsonly
published
joureview
A.
Krassnigg
A.
H. C.
Pauli
H. C.
000175246400042
0920-5632
Karl Franzens Univ Graz, Inst Theoret Phys, A-8010 Graz, Austria
MPI für Kernphysik
Group D. Schwalm
2003
2003-08-07 14:34:27.953396
oai:edoc.mpg.de:281932003-07-1137:452
Article
Renormalization of an effective model Hamiltonian by a counterterm
English
2002-04
239
241
Nuclear Physics B-Proceedings Supplements
Nucl. Phys. B-Proc. Suppl.
108
An ill-defined integral equation for modeling the mass-spectrum of mesons is regulated with an additional but unphysical parameter. This parameter dependance is removed by renormalization. Illustrative graphical examples are given.
expertsonly
published
joureview
M.
Frewer
M.
T.
Frederico
T.
H. C.
Pauli
H. C.
000175246400039
0920-5632
Ctr Tecn Aeroesp, Dept Fis, Inst Tecnol Aeronaut, BR-12228900 Sao Jose Dos Campos, SP, Brazil
MPI für Kernphysik
Group D. Schwalm
2003
2003-07-11 14:00:38.674711
oai:edoc.mpg.de:281942003-08-0737:452
Article
Renormalized QCD-inspired model for the pion and mesons
English
2002-04
234
238
Nuclear Physics B-Proceedings Supplements
Nucl. Phys. B-Proc. Suppl.
108
We apply the subtraction method to an effective QCD-inspired model, which includes the Coulomb plus a zero-range hyperfine interactions, to define a renormalized Hamiltonian for mesons. The spectrum of the renormalized Hamiltonian agrees with the one obtained with a smeared hyperfine interaction. The masses of the low-lying pseudoscalar and vector mesons are reasonably described within the model.
expertsonly
published
joureview
T.
Frederico
T.
M.
Frewer
M.
H. C.
Pauli
H. C.
000175246400038
0920-5632
Ma
MPI für Kernphysik
Group D. Schwalm
2003
2003-08-07 14:32:57.717879
oai:edoc.mpg.de:282342003-08-0737:452
Article
Symmetry properties of the k-body embedded unitary Gaussian ensemble of random matrices
English
2002-05-01
344
362
Annals of Physics
Ann. Phys.
2
297
We extend the recent study of the k-body embedded Gaussian ensembles by L. Benet, T. Rupp. and H. A. Weidenmuller (2001. Benet. Phys. Rev. Lett. 87, 101601-1 and 2001, Aim. Phys. (N.Y.) 292. 67) and by T Asaga. L. Benet. T. Rupp. and H. A. Weidenmuller (cond-mat/0107363 and condmat/0107364). We show that central results of these papers can be derived directly from the symmetry properties of both the many-particle states and the random k-body interaction. We offer new insight into the structure of the matrix of second moments of the embedded ensemble and of the supersymmetry approach. We extend the concept of the embedded ensemble and define it purely group- theoretically. (C) 2002 Elsevier Science (USA).
expertsonly
published
joureview
Z.
Pluhar
Z.
H. A.
Weidenmüller
H. A.
000175912400006
0003-4916
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:59:38.775126
oai:edoc.mpg.de:282352003-08-0737:452
Article
Mixing of bound and unbound levels
English
2002-05-16
63
68
Physics Letters B
Phys. Lett. B
1-4
534
We consider a system of two discrete levels coupled to a channel. The levels are close to threshold. We investigate the influence of the channel threshold on positions and widths of the levels. We introduce a simple parameterization of the energy dependence of the coupling matrix elements. Simple examples demonstrate the importance of this dependence. (C) 2002 Published by Elsevier Science B.V.
expertsonly
published
joureview
P.
von Brentano
P.
R. V.
Jolos
R. V.
H. A.
Weidenmüller
H. A.
000175909300009
0370-2693
Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany; Joint Inst Nucl Res, Bogoliubov Lab Theoret Phys, Dubna 141980, Russia; Univ Giessen, Inst Theoret Phys, D-35392 Giessen
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:58:54.962772
oai:edoc.mpg.de:282562003-08-0737:452
Article
Spectral properties of the k-body embedded Gaussian ensembles of random matrices for bosons
English
2002-06-15
229
247
Annals of Physics
Ann. Phys.
2
298
We consider m spinless Bosons distributed over I degenerate single-particle states and interacting through a k-body random interaction with Gaussian probability distribution (the Bosonic embedded k-body ensembles). We address the cases of orthogonal and unitary symmetry in the limit of infinite matrix dimension, attained either as l --> infinity, or as m --> infinity. We derive an eigenvalue expansion for the second moment of the many-body matrix elements of these ensembles. Using properties of this expansion, the supersymmetry technique, and the binary correlation method, we show that in the limit l --> infinity the ensembles have nearly the same spectral properties as the corresponding Fermionic embedded ensembles. Novel features specific for Bosons arise in the dense limit defined as m --> infinity with both k and l fixed. Here we show that the ensemble is not ergodic and that the spectral fluctuations are not of Wigner-Dyson type. We present numerical results for the dense limit using both ensemble unfolding and spectral unfolding. These differ strongly, demonstrating the lack of ergodicity of the ensemble. Spectral unfolding shows a strong tendency toward picket-fence-type spectra. Certain eigenfunctions of individual realizations of the ensemble display Fock-space localization. (C) 2002 Elsevier Science (USA).
expertsonly
published
joureview
T.
Asaga
T.
L.
Benet
L.
T.
Rupp
T.
H. A.
Weidenmüller
H. A.
000176371600001
0003-4916
Nihon Univ, Coll Sci & Technol, Phys Lab, Funabashi, Chiba 2748501, Japan;
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:30:28.493214
oai:edoc.mpg.de:282602003-07-1137:452
Article
Bayesian analysis of level-spacing distributions for chaotic systems with broken symmetry
English
2002-05
056221
056221
056221
Physical Review E
Phys. Rev. E
5
65
Bayesian inference is applied to the nearest-neighbor and next- nearest-neighbor spacing distributions of levels of coupled superconducting microwave billiards. The weakly coupled resonators are equivalent to a quantum system with a partially broken symmetry. The coupling parameters are obtained with help from Bayes's theorem. This procedure does not require the introduction of a set of bins. The results are more accurate than those obtained from other bin-independent procedures.
expertsonly
published
joureview
A. Y.
Abul-Magd
A. Y.
C.
Dembowski
C.
H. L.
Harney
H. L.
M. H.
Simbel
M. H.
000176552500070
1063-651X
Zagazig Univ, Fac Sci, Zagazig, Egypt; TH Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany
MPI für Kernphysik
Guest Groups and Emeriti
2003
2003-07-11 11:46:46.348261
oai:edoc.mpg.de:288452003-07-1437:452
Article
On the form factor of physical mesons and their distribution function
English
2002-07-01
73
89
Nuclear Physics A
Nucl. Phys. A
1-2
705
This work addresses more to the technical rather than to the physical problem, how to calculate analytically the form factor F(Q), the associated mean-square radius (r(2)), and the distribution function Phi(x, Q(2)) for a given light-cone wave function psi(q)((q)) over bar (x, (k) over right arrow (perpendicular to)) of the pion. They turn out to be functions of only one dimensionless parameter, which is the ratio of the constituent quark mass and an effective Bohr momentum which measures the width of the wave function in momentum space. Both parameters are subject to change in the future, when the presently used solution for the over simplified up arrowdown arrow-model will be replaced by something better. Their relation to and agreement with experiment is discussed in detail. The procedure can be generalized also to other hadrons. (C) 2002 Elsevier Science B.V. All rights reserved.
expertsonly
published
joureview
H. C.
Pauli
H. C.
000176944500005
0375-9474
MPI für Kernphysik
Group D. Schwalm
2003
2003-07-14 15:51:38.70505
oai:edoc.mpg.de:288462003-08-0737:452
Article
Random matrix approach to cross correlations in financial data
English
2002-06
066126
066126
066126
Physical Review E
Phys. Rev. E
6
65
We analyze cross correlations between price fluctuations of different stocks using methods of random matrix theory (RMT). Using two large databases, we calculate cross-correlation matrices C of returns constructed from (i) 30-min returns of 1000 US stocks for the 2-yr period 1994-1995, (ii) 30-min returns of 881 US stocks for the 2-yr period 1996-1997, and (iii) 1-day returns of 422 US stocks for the 35-yr period 1962- 1996. We test the statistics of the eigenvalues lambda(i) of C against a "null hypothesis" - a random correlation matrix constructed from mutually uncorrelated time series. We find that a majority of the eigenvalues of C fall within the RMT bounds [lambda(-),lambda(+)] for the eigenvalues of random correlation matrices. We test the eigenvalues of C within the RMT bound for universal properties of random matrices and find good agreement with the results for the Gaussian orthogonal ensemble of random matrices-implying a large degree of randomness in the measured cross-correlation coefficients. Further, we find that the distribution of eigenvector components for the eigenvectors corresponding to the eigenvalues outside the RMT bound display systematic deviations from the RMT prediction. In addition, we find that these "deviating eigenvectors" are stable in time. We analyze the components of the deviating eigenvectors and find that the largest eigenvalue corresponds to an influence common to all stocks. Our analysis of the remaining deviating eigenvectors shows distinct groups, whose identities correspond to conventionally identified business sectors. Finally, we discuss applications to the construction of portfolios of stocks that have a stable ratio of risk to return.
expertsonly
published
joureview
V.
Plerou
V.
P.
Gopikrishnan
P.
B.
Rosenow
B.
L. A. N.
Amaral
L. A. N.
T.
Guhr
T.
H. E.
Stanley
H. E.
000176762900033
1063-651X
Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA; Boston Univ, Dept Phys, Boston, MA 02215 USA; Boston Coll, Dept Phys, Chestnut Hill, MA 02167, USA; Harvard Univ, Dept Phys, Cambridge, MA 02138 USA; ; Lund Univ, LTH, Lund, Sweden
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 14:28:41.699339
oai:edoc.mpg.de:288492003-08-0737:452
Article
Transmission phase of an isolated Coulomb blockade resonance
English
2002-06-15
245322
245322
245322
Physical Review B
Phys. Rev. B
24
65
In two recent papers, O. Entin-Wohlman [cond-mat/0109328 (unpublished) and (private communication)] studied the question: "Which physical information is carried by the transmission phase through a quantum dot?" In the present paper, this question is answered for an islolated Coulomb blockade resonance and within a theoretical model which is more closely patterned after the geometry of the actual experiment by Schuster [Nature 385, 417 (1997)] than is the model of O. Entin-Wohlman We conclude that whenever the number of leads coupled to the Aharanov-Bohm interferometer is larger than two, and the total number of channels is sufficiently large, the transmission phase does reflect the Breit-Wigner behavior of the resonance phase shift.
expertsonly
published
joureview
H. A.
Weidenmüller
H. A.
000177043100081
0163-1829
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:56:58.077144
oai:edoc.mpg.de:288662003-08-0737:452
Article
Sympathetic cooling and growth of a Bose-Einstein condensate
English
2002-08
025603
025603
025603
Physical Review A
Phys. Rev. A
2
66
We study two sets of rate equations for sympathetic cooling of harmonically trapped Bose gases. Calculations for mixtures of Na-Rb and Li-Cs show that both sets yield similar results for the cooling times. The equilibration rates are in fair agreement with each other and differ considerably from classical rates. The onset of Bose-Einstein condensation is rather sudden and nonexponential in time, and the growth of the condensate differs for the two different mixtures we studied.
expertsonly
published
joureview
T.
Papenbrock
T.
A. N.
Salgueiro
A. N.
H. A.
Weidenmüller
H. A.
000177872600146
1050-2947
Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831, USA
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
MPI für Physik Komplexer Systeme
2003
2003-08-07 13:54:31.565865
oai:edoc.mpg.de:288712003-08-0737:452
Article
Critical correlations of Wilson lines in SU(3) and the high energy gamma(*)p cross section
English
2002-08-01
034020
034020
034020
Physical Review D
Phys. Rev. D
3
66
expertsonly
published
joureview
H. J.
Pirner
H. J.
F.
Yuan
F.
000177873600044
0556-2821
Univ Heidelberg, Inst Theoret Phys, Heidelberg, Germany
MPI für Kernphysik
Guest Groups and Emeriti
2003
2003-08-07 13:52:20.499885
oai:edoc.mpg.de:288722003-08-0737:452
Article
S-matrix unitarity, impact parameter profiles, gluon saturation and high-energy scattering
English
2002-10-21
131
183
Nuclear Physics A
Nucl. Phys. A
709
A model combining perturbative and non-perturbative QCD is developed to compute high-energy reactions of hadrons and photons and to investigate saturation effects that manifest the S-matrix unitarity. Following a functional integral approach, the S-matrix factorizes into light-cone wave functions and the universal amplitude for the scattering of two color-dipoles which are represented by Wegner-Wilson loops. In the framework of the non-perturbative stochastic vacuum model of QCD supplemented by perturbative gluon exchange, the loop-loop correlation is calculated and related to lattice QCD investigations. With a universal energy dependence motivated by the two-pomeron (soft + hard) picture that respects the unitarity condition in impact parameter space, a unified description of pp, pip, Kp, gamma*p, and gammagamma reactions is achieved in good agreement with experimental data for cross sections, slope parameters, and structure functions. Impact parameter profiles for pp and gamma(L)*p reactions and the gluon distribution of the proton xG(x, Q(2), \(b) over right arrow (perpendicular to)\) are calculated and found to saturate in accordance with S-matrix unitarity. The c.m. energies and Bjorken x at which saturation sets in are determined. (C) 2002 Elsevier Science B.V. All rights reserved.
gluon saturation; high-energy scattering; impact parameter profiles; loop-loop scattering; multiple-gluon exchange; pomeron; QCD; stochastic vacuum model; unitarity
expertsonly
published
joureview
A. I.
Shoshi
A. I.
F. D.
Steffen
F. D.
H. J.
Pirner
H. J.
000178222300007
0375-9474
Univ Heidelberg, Inst Theoret Phys, D-69120 Heidelberg, Germany
MPI für Kernphysik
Guest Groups and Emeriti
2003
2003-08-07 13:50:14.258305
oai:edoc.mpg.de:288732003-08-0737:452
Article
Integration over matrix spaces with unique invariant measures
English
2002-10
5135
5144
Journal of Mathematical Physics
J. Math. Phys.
10
43
We present a method to calculate integrals over monomials of matrix elements with invariant measures in terms of Wick contractions. The method gives exact results for monomials of low order. For higher-order monomials, it leads to an error of order 1/N-alpha, where N is the dimension of the matrix and where alpha is independent of the degree of the monomial. We give a lower bound on the integer alpha and show how alpha can be increased systematically. The method is particularly suited for symbolic computer calculation. Explicit results are given for O(N), U(N), and for the circular orthogonal ensemble. (C) 2002 American Institute of Physics.
expertsonly
published
joureview
T.
Prosen
T.
T. H.
Seligman
T. H.
H. A.
Weidenmüller
H. A.
000178095500041
0022-2488
Univ Ljubljana, Fac Math & Phys, Dept Phys, Ljubljana, Slovenia; Ctr Int Ciencias, Cuernavaca, Morelos, Mexico; Univ Mexico, UNAM, Ctr Ciencias Fis, Mexico City, DF, Mexico
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:56:18.744676
oai:edoc.mpg.de:288782003-08-0737:452
Article
Mean-field approximation to the master equation for sympathetic cooling of trapped bosons
English
2002-09
033608
033608
033608
Physical Review A
Phys. Rev. A
3
66
We use the mean-field approximation to simplify the master equation for sympathetic cooling of bosons. For the mean single-particle occupation numbers, this approach yields the same equations as the factorization assumption introduced in an early paper. The stationary or equilibrium solution of the resulting master equation for the one-body density matrix shows that the mean-field approximation breaks down whenever the fraction of condensate bosons exceeds 10% or so of the total. Using group-theoretical methods, we also solve the time- dependent master equation for the one-body density matrix. Given the time dependence of the mean single-particle occupation numbers, this solution is obtained by quadratures. It tends asymptotically towards the equilibrium solution.
expertsonly
published
joureview
S. J.
Wang
S. J.
M. C.
Nemes
M. C.
A. N.
Salgueiro
A. N.
H. A.
Weidenmüller
H. A.
000178382500100
1050-2947
Lanzhou Univ, Dept Modern Phys, Lanzhou 730000, Peoples R China; Univ Fed Minas Gerais, Dept Phys, Belo Horizonte, MG, Brazil;
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:47:00.652358
oai:edoc.mpg.de:288792003-08-0737:452
Article
Splitting of the pi-rho spectrum in a renormalized light-cone QCD-inspired model
English
2002-09-01
054007
054007
054007
Physical Review D
Phys. Rev. D
5
66
We show that the splitting between the light pseudoscalar and vector meson states is due to the strong short-range attraction in the S-1(0) sector which makes the pion and the kaon light particles. We use a light-cone QCD-inspired model of the mass squared operator with harmonic confinement and a Dirac-delta interaction. We apply a renormalization method to define the model, in which the pseudoscalar ground state mass fixes the renormalized strength of the Dirac-delta interaction.
expertsonly
published
joureview
T.
Frederico
T.
H. C.
Pauli
H. C.
S. G.
Zhou
S. G.
000178460700028
0556-2821
Ctr Tecn Aeroesp, Inst Tecnol Aeronaut, Dept Fis, BR-12228900 Sao Paulo, Brazil; Peking Univ, Sch Phys, Beijing 100871, Peoples R China
MPI für Kernphysik
Guest Groups and Emeriti
2003
2003-08-07 13:45:13.358875
oai:edoc.mpg.de:288992003-08-0737:452
Article
Thermal noise in a solid state quantum computer
English
2002-10-21
2499
2502
Journal of Physics D-Applied Physics
J. Phys. D-Appl. Phys.
20
35
The Kane proposal for the construction of a solid state quantum computer calls for the placement of a metallic A-gate above each nuclear qubit. Voltage biases applied to these A-gates are to be used to control the evolution of the qubits. In this paper, we consider the decohering effect of thermal fluctuations, the so-called Johnson noise, in the A-gate biases, on the average evolution of qubits undergoing single qubit rotations, as well as those that are not undergoing any operation at all. We find that although the errors introduced are of a different nature for each case, phase errors for the static qubits and both phase and bit-flip errors for qubits undergoing operations, the net error probability is similar for both, and low enough when compared to the timescale of single qubit operations for them to be corrected efficiently.
expertsonly
published
joureview
C. J.
Wellard
C. J.
L. C. L.
Hollenberg
L. C. L.
000179131600010
0022-3727
Univ Melbourne, Sch Phys, Ctr Quantum Comp Technol, Melbourne, Vic, Australia;
MPI für Kernphysik
Guest Groups and Emeriti
2003
2003-08-07 13:43:46.850749
oai:edoc.mpg.de:291242003-08-0737:452
Article
Decomposition of the QCD string into dipoles and unintegrated gluon distributions
English
2002-11-01
094019
094019
094019
Physical Review D
Phys. Rev. D
9
66
We present the perturbative and non-perturbative QCD structure of the dipole-dipole scattering amplitude in momentum space. The perturbative contribution is described by the two-gluon exchange and the non-perturbative contribution by the stochastic vacuum model which leads to confinement of the quark and antiquark in the dipole via a string of color fields. This QCD string gives important nonperturbative contributions to high-energy reactions. A new structure different from the perturbative dipole factors is found in the string-string scattering amplitude. The string can be represented as an integral over stringless dipoles with a given dipole number density. This decomposition of the QCD string into dipoles allows us to calculate the unintegrated gluon distribution of hadrons and photons from the dipole-hadron and dipole-photon cross section via \(k) over right arrow (perpendicular to)\ factorization.
notspecified
published
joureview
A. I.
Shoshi
A. I.
F. D.
Steffen
F. D.
H. G.
Dosch
H. G.
H. J.
Pirner
H. J.
000179679400036
0556-2821
Univ Heidelberg, Inst Theoret Phys, D-69120 Heidelberg, Germany
MPI für Kernphysik
Guest Groups and Emeriti
2003
2003-08-07 13:42:05.161357
oai:edoc.mpg.de:291482003-08-0737:452
Article
Universal description of S-wave meson spectra in a renormalized light-cone QCD-inspired model
English
2002-12-01
116011
116011
116011
Physical Review D
Phys. Rev. D
11
66
A light-cone QCD-inspired model, with the mass squared operator consisting of a harmonic oscillator potential as confinement and a Dirac delta interaction, is used to study S-wave meson spectra. The two parameters of the harmonic potential and quark masses are fixed by the masses of rho(770), rho(1450), J/psi, psi(2S), K*(892), and B*. We apply a renormalization method to define the model, in which the pseudoscalar ground state mass fixes the renormalized strength of the Dirac delta interaction. The model presents a universal and satisfactory description of both singlet and triplet states of S-wave mesons and the corresponding radial excitations.
expertsonly
published
joureview
T.
Frederico
T.
H. C.
Pauli
H. C.
S. G.
Zhou
S. G.
000180317600062
0556-2821
Ctr Tecn Aeroesp, Inst Tecnol Aeronaut, Dept Fis, BR-12228900 Sao Jose Dos Campos, Brazil; Peking Univ, Sch Phys, Beijing 100871, Peoples R China
MPI für Kernphysik
Group D. Schwalm
2003
2003-08-07 13:40:30.818787
oai:edoc.mpg.de:291512003-07-1637:452
Article
Observation of a chiral state in a microwave cavity
English
2003-01-24
034101
034101
034101
Physical Review Letters
Phys. Rev. Lett.
3
90
A microwave experiment has been realized to measure the phase difference of the oscillating electric field at two points inside the cavity. The technique has been applied to a dissipative resonator which exhibits a singularity-called exceptional point-in its eigenvalue and eigenvector spectrum. At the singularity, two modes coalesce with a phase difference of pi/2. We conclude that the state excited at the singularity has a definitive chirality.
expertsonly
published
joureview
C.
Dembowski
C.
B.
Dietz
B.
H. D.
Graf
H. D.
H. L.
Harney
H. L.
A.
Heine
A.
W. D.
Heiss
W. D.
A.
Richter
A.
000180579200017
0031-9007
Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany; Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany; Univ Stellenbosch, Dept Phys, ZA-7602 Matieland, South Africa
MPI für Kernphysik
Group W. Hofmann
2003-07-16 10:33:04.112169
oai:edoc.mpg.de:292272003-07-1637:452
Article
Experimental versus simulated Coulomb-explosion images of flexible molecules: Structure of protonated acetylene C2H3+
English
2003-02
022506
022506
022506
Physical Review A
Phys. Rev. A
2
67
The most probable structure of protonated acetylene C2H3+ (the "vinyl cation") is inferred from both Coulomb-explosion experiments and finite-temperature ab initio quantum simulations followed by simulations of foil effects. It is found that C2H3+ features significant deviations from the planar bridged equilibrium structure as well as from the planar Y-shaped local minimum structure, which are known from static electronic structure calculations. In particular, the "axial protons" feature a significant out-of-plane trans-bending due to fluctuation effects. This implies that the nonplanarity has to be taken into account in theoretical treatments that aim at describing this fluxional molecule.
expertsonly
published
joureview
L.
Knoll
L.
Z.
Vager
Z.
D.
Marx
D.
000181361200051
1050-2947
Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel; Ruhr Univ Bochum, Lehrstuhl Theoret Chem, D-44780 Bochum, Germany
MPI für Kernphysik
Guest Groups and Emeriti
2004
2003-07-16 14:11:27.17945
oai:edoc.mpg.de:292332003-08-0737:452
Article
Character expansions for the orthogonal and symplectic groups
English
2002-01
604
620
Journal of Mathematical Physics
J. Math. Phys.
1
43
Formulas for the expansion of arbitrary invariant group functions in terms of the characters for the Sp(2N), SO(2N+1), and SO(2N) groups are derived using a combinatorial method. The method is similar to one used by Balantekin to expand group functions over the characters of the U(N) group. All three expansions have been checked for all N by using them to calculate the known expansions of the generating function of the homogeneous symmetric functions. An expansion of the exponential of the traces of group elements, appearing in the finite-volume gauge field partition functions, is worked out for the orthogonal and symplectic groups. (C) 2002 American Institute of Physics.
expertsonly
published
joureview
A. B.
Balantekin
A. B.
P.
Cassak
P.
000172790200037
0022-2488
Univ Wisconsin, Dept Phys, Madison, WI 53706 USA
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:38:54.254653
oai:edoc.mpg.de:292352004-06-1137:452
Article
Decoherence in chaotic and integrable systems: a random matrix approach
English
2003-03-17
61
67
Physics Letters A
Phys. Lett. A
1-2
309
We study the influence of chaos and order on entanglement and decoherence. In view of applications in quantum computing and teleportation which should be able to work with arbitrarily complicated states, we pay particular attention to the behavior of random states. While studies with coherent states indicate that chaos accelerates decoherence and entanglement, we find that there is practically no difference between the chaotic and the integrable case, as far as random states are concerned. In the present studies we use unitary time evolution of the total system, and partial traces to emulate decoherence. Random matrix models are a natural choice to describe the dynamics of random states. The invariant aspects of chaos and order are then reflected in the different spectral statistics. We develop random matrix models for the evolution of entanglement for a large variety of situations, discussing the strong coupling case in full detail. (C) 2003 Elsevier Science B.V. All rights reserved.
expertsonly
published
joureview
T.
Gorin
T.
T. H.
Seligman
T. H.
000181589000009
0375-9601
Univ Nacl Autonoma Mexico, Ctr Ciencias Fis, Avenida Univ S-N,; Cuernavaca 62210, Morelos, Mexico; Univ Nacl Autonoma Mexico, Ctr Ciencias Fis, Cuernavaca 62210, Morelos, Mexico
MPI für Kernphysik
Guest Groups and Emeriti
2004
2004-06-11 14:18:34.709488
oai:edoc.mpg.de:292412003-07-1637:452
Article
EDM operator free from Schiff's theorem
English
2001-12
1223
1238
Progress of Theoretical Physics
Prog. Theor. Phys.
6
106
We present a generalization of Schiff's transformation of electric dipole moments (EDM) in quantum field theory. Under the unitary transformation, the time and parity violating interaction i ge/2 (ψ) over bar sigma(muv) gamma(5) psi F- muv is transformed into a new form, but its nonrelativistic reduction has a unique form to which Schiff's theorem does not apply. The relativistic corrections to the new EDM operator slightly increase the EDM, as given by b(2) (alphaZ)(2) with b(2) similar or equal to 2. It is thus seen that the calculation of the EDM with nonrelativistic Hartree-Fock wave functions presents a conservative but reliable estimation for the enhancement factor of the EDM in atoms.
expertsonly
published
joureview
T.
Asaga
T.
T.
Fujita
T.
M.
Hiramoto
M.
000173081000010
0033-068X
Nihon Univ, Dept Phys, Fac Sci & Technol, Tokyo 1018308, Japan
MPI für Kernphysik
Guest Groups and Emeriti
2003-07-16 13:27:59.270514
oai:edoc.mpg.de:328162003-08-0737:452
Article
Quantum corrections to the ground state energy of inhomogeneous neutron matter
English
2002-06-03
892
892
Nuclear Physics A
Nucl. Phys. A
3-4
703
expertsonly
published
notspecified
A.
Bulgac
A.
P.
Magierski
P.
000177378700017
0375-9474
Univ Washington, Dept Phys, Seattle, WA 98195 USA; Warsaw Univ Technol, Inst Phys, PL-00662 Warsaw, Poland
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:36:45.683634
oai:edoc.mpg.de:328192003-08-0737:452
Article
Effective dielectric constant of a two-component material with shape distribution
English
2002-02-07
267
271
Journal of Physics D-Applied Physics
J. Phys. D-Appl. Phys.
3
35
The effective dielectric constant of a two-component material is investigated. By considering the shape distribution of the components, we derive Maxwell-Garnett-type approximation, which has been established based on the reciprocity theorem (del Rio J A et al 1998 Solid State Commun. 106 183). Based on a self- consistent condition on the electric field (Bruggeman-type effective medium approximation), we obtain the well-known Lichtenecker's mixture formulae with alpha = 1/2. Moreover, we derive the differential effective medium approximation by taking into account the shape distribution. All these formulae are checked through the spectral density function and compared with previous bounds.
expertsonly
published
joureview
L.
Gao
L.
J. Z.
Gu
J. Z.
000174238800018
0022-3727
CCAST, World Lab, Beijing 100080, Peoples R China; Suzhou Univ, Dept Phys, Suzhou 215006, Peoples R China; Nanjing Univ, Solid State Microstruct Lab, Nanjing 210008, Peoples R China
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:35:18.940997
oai:edoc.mpg.de:328202003-07-2137:452
Article
Three-body confinement force in hadron spectroscopy
English
2002-03-01
054032
054032
054032
Physical Review D
Phys. Rev. D
5
65
Recently it has been argued that a three-body color confinement interaction can affect the stability condition of a three-quark system and the spectrum of a tetraquark described by any constituent quark model. Here we discuss the role of a three- body color confinement interaction in a simple quark model and present some of its implications for the spectra of baryons, tetraquarks and six-quark systems.
expertsonly
published
joureview
S.
Pepin
S.
F.
Stancu
F.
000174548000064
0556-2821
Univ Liege, Inst Phys B5, B-4000 Liege, Belgium; ECT, I-38050 Trent, Italy
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-07-21 13:17:44.828316
oai:edoc.mpg.de:328232003-07-2137:452
Article
Scaling behavior of layered high-T-c superconductors with columnar defects
English
2002-02-01
054512
054512
054512
Physical Review B
Phys. Rev. B
5
6505
It was recently observed [van der Beek et al., Phys, Rev. B 54, R792 (1996)] that irradiated layered high-T-c superconductors subject to perpendicular magnetic field manifest two similar scaling behaviors corresponding to two different critical temperatures. We show that this phenomenon is explained within the framework of the Ginzburg-Landau theory. In the weak field region, the scaling function differs from that of a clean sample mainly because of the renormalization of the critical temperature, due to defects. In the strong field region, defects are effectively suppressed and the scaling function, as well as the critical temperature, are the same as in a clean superconductor, The theory presented here agrees quite satisfactory with experiment.
expertsonly
published
joureview
G. M.
Braverman
G. M.
S. A.
Gredeskul
S. A.
Y.
Avishai
Y.
000173647000085
0163-1829
Ben Gurion Univ Negev, Beer Sheva, Israel
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-07-21 13:12:32.428561
oai:edoc.mpg.de:328272003-08-0737:452
Article
Classical scattering from oscillating targets
English
2002-12-30
116
126
Physics Letters A
Phys. Lett. A
2-3
306
We study planar classical scattering from an oscillating heavy target whose dynamics defines a five-dimensional phase space. Although the system possesses no periodic orbits, and thus topological chaos is not present, the scattering functions display a variety of structures on different time scales. These structures are due to scattering events with a strong energy transfer from the projectile to the moving disk resulting in low-velocity peaks. We encounter initial conditions for which the projectile exhibits infinitely many bounces with the oscillating disk. Our numerical investigations are supported by analytical results on a specific model with a simple time-law. The observed properties possess universal character for scattering off oscillating targets. (C) 2002 Elsevier Science B.V. All rights reserved.
expertsonly
published
joureview
P. K.
Papachristou
P. K.
F. K.
Diakonos
F. K.
V.
Constantoudis
V.
P.
Schmelcher
P.
L.
Benet
L.
000180382100010
0375-9601
Univ Heidelberg, Inst Chem Phys, D-69120 Heidelberg, Germany; Univ Athens, Dept Phys, GR-15771 Athens, Greece; Natl Tech Univ Athens, Dept Phys, Athens 15780, Greece; Univ Nacl Autonoma Mexico, Ctr Ciencias Fis, Cuernavaca 62210, Morelos, Mexico
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003
2003-08-07 13:34:12.745764
oai:edoc.mpg.de:330282003-07-2137:452
Article
Occurrence of planetary rings with shepherds
English
2001
123
128
Celestial Mechanics & Dynamical Astronomy
Celest. Mech. Dyn. Astron.
1-2
81
We consider the system of planetary rings with shepherds as a restricted three or four-body problem, neglecting interactions between ring particles. We show that the generic occurrence of rings for the case of rotating short-range potentials can be extended to the case of gravitational potentials. The consecutive collision periodic orbits created by saddle-center bifurcations are of central importance.
planetary rings; shepherd moons; periodic orbits
expertsonly
published
joureview
L.
Benet
L.
000173686100015
0923-2958
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2003-07-21 12:01:16.655808
oai:edoc.mpg.de:604922004-06-1137:452
Article
Crossing of two Coulomb blockade resonances
English
2003
125326
125334
Physical Review B (Condensed Matter and Materials Physics -15(II))
68
We investigate theoretically the transport of noninteracting electrons through an Aharanov-Bohm (AB) interferometer with two quantum dots (QD's) embedded into its arms. In the Coulomb blockade regime, transport through each QD proceeds via a single resonance. The resonances are coupled through the arms of the AB device, but may also be coupled directly. In the framework of the Landauer-Büttiker approach, we present expressions for the scattering matrix which depend explicitly on the energies of the two resonances and on the AB phase. We pay particular attention to the crossing of the two resonances.
expertsonly
published
joureview
H. A.
Weidenmüller
H. A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-06-11 14:17:33.292709
©2003 The American Physical Society
oai:edoc.mpg.de:608712004-01-2137:452
Article
Review of the k-body embedded ensembles of Gaussian random matrices
English
2003-03-28
3569
3593
Journal of Physics A: Mathematical and General
J. Phys. A: Math. Gen.
36
The embedded ensembles were introduced by Mon and French (1975 Ann. Phys., NY 95 90) as physically more plausible stochastic models of many-body systems governed by one- and two-body interactions than provided by standard random-matrix theory. We review several approaches aimed at determining the spectral density, the spectral fluctuation properties and the ergodic properties of these ensembles: moments methods, numerical simulations, the replica trick, the eigenvector decomposition of the matrix of second moments and supersymmetry, the binary correlation approximation, and the study of correlations between matrix elements.
expertsonly
published
joureview
L.
Benet
L.
H.A.
Weidenmüller
H.A.
Centro de Ciencias Físicas, UNAM (Unidad Morelos), 62210 Cuernavaca, Mor, Mexico
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-01-21 11:01:43.712856
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Copyright © Institute of Physics and IOP Publishing Limited 2004.
oai:edoc.mpg.de:611252004-01-2337:452
Article
Localization properties of two interacting electrons in a disordered quasi one-dimensional potential
English
2003
3281
3288
Journal of Physics A: Mathematical and General
36
We study the transport properties of two electrons in a quasi one-dimensional disordered wire. The electrons are subject to both a disorder potential and a short range two-body interaction. Using the approach developed by Iida et al (1990 Ann. Phys., NY 200 219), the supersymmetry technique and a suitable truncation of Hilbert space, we work out the two-point correlation function in the framework of a nonlinear model. We study the loop corrections to arbitrary order. We obtain a remarkably simple and physically transparent expression for the change of the localization length caused by the two-body interaction.
expertsonly
published
joureview
J.
Richert
J.
H.A.
Weidenmüller
H.A.
Laboratoire de Physique Théorique, Université Louis Pasteur, 67084 Strasbourg Cedex, France
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-01-23 09:52:50.371663
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Author: Vol/Year: Issue: Page/Article No:
Copyright © Institute of Physics and IOP Publishing Limited 2004.
oai:edoc.mpg.de:612522004-01-2637:452
Article
Two interacting electrons in a disorder potential: localization properties
English
2003
96
131
Annals of Physics
Ann. Phys.
306
Two electrons move in a quasi one-dimensional wire under the influence of a short-range interaction. We restrict Hilbert space to those states where the two electrons are close to each other. Using supersymmetry, we present a complete analytical solution to this problem. The two-body interaction affects the density of states and, thereby, the localization length. We derive a criterion for the onset of changes of the localization length due to the two-body interaction.
expertsonly
published
joureview
J.
Richert
J.
H.A.
Weidenmüller
H.A.
Laboratoire de Physique Théorique, Université Louis Pasteur, Strasbourg, France
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-01-26 09:41:07.972329
Copyright © 2003 Elsevier Science (USA). All rights reserved.
oai:edoc.mpg.de:612532004-01-2637:452
Article
Spectral Properties of the k-Body Embedded Gaussian Ensembles of Random Matrices for Bosons
English
2002
229
249
Annals of Physics
Ann. Phys.
298
We consider m spinless Bosons distributed over l degenerate single-particle states and interacting through a k-body random interaction with Gaussian probability distribution (the Bosonic embedded k-body ensembles). We address the cases of orthogonal and unitary symmetry in the limit of infinite matrix dimension, attained either as l goes against infiniti or as m goes adainst infiniti. We derive an eigenvalue expansion for the second moment of the many-body matrix elements of these ensembles. Using properties of this expansion, the supersymmetry technique, and the binary correlation method, we show that in the limit l goes against infiniti the ensembles have nearly the same spectral properties as the corresponding Fermionic embedded ensembles. Novel features specific for Bosons arise in the dense limit defined as m goes against infiniti with both k and l fixed. Here we show that the ensemble is not ergodic and that the spectral fluctuations are not of Wigner-Dyson type. We present numerical results for the dense limit using both ensemble unfolding and spectral unfolding. These differ strongly, demonstrating the lack of ergodicity of the ensemble. Spectral unfolding shows a strong tendency toward picket-fence-type spectra. Certain eigenfunctions of individual realizations of the ensemble display Fock-space localization.
expertsonly
published
joureview
T.
Asaga
T.
L.
Benet
L.
T.
Rupp
T.
H.A.
Weidenmüller
H.A.
Laboratory of Physics, College of Science and Technology, Nihon University, 7-24-1 Narashino-dai, Funabashi, Chiba, Japan 274-8501
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-26 09:58:34.085827
Copyright © 2002 Elsevier Science (USA). All rights reserved.
oai:edoc.mpg.de:612552004-01-2637:452
Article
Symmetry Properties of the k-Body Embedded Unitary Gaussian Ensemble of Random Matrices
English
2002
344
362
Annals of Physics
Ann. Phys.
2
297
We extend the recent study of the k-body embedded Gaussian ensembles by L. Benet, T. Rupp, and H. A. Weidenmüller (2001, Benet, Phys. Rev. Lett.87, 101601-1 and 2001, Ann. Phys. (N.Y.)292, 67) and by T. Asaga, L. Benet, T. Rupp, and H. A. Weidenmüller (cond-mat/0107363 and cond-mat/0107364). We show that central results of these papers can be derived directly from the symmetry properties of both the many-particle states and the random k-body interaction. We offer new insight into the structure of the matrix of second moments of the embedded ensemble and of the supersymmetry approach. We extend the concept of the embedded ensemble and define it purely group-theoretically.
expertsonly
published
joureview
Z.
Pluhar
Z.
H.A.
Weidenmüller
H.A.
Charles University, Prague, Czech Republic
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-26 10:16:08.12519
Copyright © 2002 Elsevier Science (USA). All rights reserved.
oai:edoc.mpg.de:612592004-01-2637:452
Article
Rate equations for sympathetic cooling of trapped bosons or fermions
English
2002
1
14
043601
Physical Review A (Atomic, Molecular, and Optical Physics)
Phys. Rev. A
65
We derive two different sets of rate equations for sympathetic cooling of harmonically trapped bosons or fermions. The rate equations are obtained from a master equation derived earlier by Lewenstein et al. [Phys. Rev. A 51, 4617 (1995)] by means of decoherence and ergodicity arguments. We show analytically that the thermal equilibrium state is a stationary solution of our rate equation. We present analytical results for the rate coefficients which are needed to solve the rate equations, and we give approximate formulas that permit their computation in practice. We solve the two sets of rate equations numerically and compare the results. The cooling times obtained in both approaches agree very well. The equilibration rates show fair agreement.
expertsonly
published
joureview
T.
Papenbrock
T.
A.N.
Salgueiro
A.N.
H.A.
Weidenmüller
H.A.
Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-26 11:45:08.899054
©2002 The American Physical Society
oai:edoc.mpg.de:612752004-01-2637:452
Article
Sympathetic cooling and growth of a Bose-Einstein condensate
English
2002
1
4
025603
Physical Review A (Atomic, Molecular, and Optical Physics)
Phys. Rev. A
66
We study two sets of rate equations for sympathetic cooling of harmonically trapped Bose gases. Calculations for mixtures of Na-Rb and Li-Cs show that both sets yield similar results for the cooling times. The equilibration rates are in fair agreement with each other and differ considerably from classical rates. The onset of Bose-Einstein condensation is rather sudden and nonexponential in time, and the growth of the condensate differs for the two different mixtures we studied.
expertsonly
published
joureview
T.
Papenbrock
T.
A.N.
Salgueiro
A.N.
H.A.
Weidenmüller
H.A.
Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
Max-Planck-Institut für Physik Komplexer Systeme, D-01187 Dresden, Germany
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-26 15:32:37.357528
©2002 The American Physical Society
oai:edoc.mpg.de:613862004-01-2737:452
InBook
Statistical Theory of Nuclear Reactions
English
Academic Press
San Diego, Calif. [u.a.]
2001
1393
1413
Scattering: scattering and inverse scattering in pure and applied science
Pike, Roy; Sabatier, Pierre
expertsonly
published
notspecified
H.A.
Weidenmüller
H.A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-27 15:31:31.42522
oai:edoc.mpg.de:618762004-03-0437:452
Article
Transmission phase of an isolated Coulomb blockade resonance
English
2002
1
6
245322
Physical Review B (Condensed Matter and Materials Physics)
Phys. Rev. B
65
In two recent papers, O. Entin-Wohlman et al. [cond-mat/0109328 (unpublished) and (private communication)] studied the question: "Which physical information is carried by the transmission phase through a quantum dot?" In the present paper, this question is answered for an islolated Coulomb blockade resonance and within a theoretical model which is more closely patterned after the geometry of the actual experiment by Schuster et al. [Nature 385, 417 (1997)] than is the model of O. Entin-Wohlman et al. We conclude that whenever the number of leads coupled to the Aharanov-Bohm interferometer is larger than two, and the total number of channels is sufficiently large, the transmission phase does reflect the Breit-Wigner behavior of the resonance phase shift.
expertsonly
published
joureview
H.A.
Weidenmüller
H.A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-03-04 09:18:09.045379
©2002 The American Physical Society
oai:edoc.mpg.de:618842004-01-2937:452
Article
Mean-field approximation to the master equation for sympathetic cooling of trapped bosons
English
2002
1
8
033608
Physical Review A (Atomic, Molecular, and Optical Physics)
Phys. Rev. A
66
We use the mean-field approximation to simplify the master equation for sympathetic cooling of bosons. For the mean single-particle occupation numbers, this approach yields the same equations as the factorization assumption introduced in an early paper. The stationary or equilibrium solution of the resulting master equation for the one-body density matrix shows that the mean-field approximation breaks down whenever the fraction of condensate bosons exceeds 10% or so of the total. Using group-theoretical methods, we also solve the time-dependent master equation for the one-body density matrix. Given the time dependence of the mean single-particle occupation numbers, this solution is obtained by quadratures. It tends asymptotically towards the equilibrium solution.
expertsonly
published
joureview
S.J.
Wang
S.J.
M.C.
Nemes
M.C.
A.N.
Salgueiro
A.N.
H.A.
Weidenmüller
H.A.
Department of Modern Physics, Lanzhou University, 730000 Lanzhou, People's Republic of China
Department of Physics, University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-29 13:44:40.272086
©2002 The American Physical Society
oai:edoc.mpg.de:618912004-01-2837:452
Article
Integration over matrix spaces with unique invariant measures
English
2002
5135
5144
Journal of Mathematical Physics
Journ. Math. Phys.
10
43
We present a method to calculate integrals over monomials of matrix elements with invariant measures in terms of Wick contractions. The method gives exact results for monomials of low order. For higher-order monomials, it leads to an error of order 1/N, where N is the dimension of the matrix and where α is independent of the degree of the monomial. We give a lower bound on the integer and show how α can be increased systematically. The method is particularly suited for symbolic computer calculation. Explicit results are given for O(N), U(N), and for the circular orthogonal ensemble.
expertsonly
published
joureview
T.
Prosen
T.
T. H.
Seligman
T. H.
H. A.
Weidenmüller
H. A.
Physics Department, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
Centro de Ciencias Físicas, University of Mexico (U.N.A.M.), and Centro Internacional de Ciencias, Cuernavaca, Mexico
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-28 11:21:15.631724
©2002 American Institute of Physics.
oai:edoc.mpg.de:621672004-01-2937:452
Article
Mixing of bound and unbound levels
English
2002
63
68
Physics Letters B
Phys. Lett. B
1-4
534
We consider a system of two discrete levels coupled to a channel. The levels are close to threshold. We investigate the influence of the channel threshold on positions and widths of the levels. We introduce a simple parameterization of the energy dependence of the coupling matrix elements. Simple examples demonstrate the importance of this dependence.
expertsonly
published
joureview
P.
von Brentano
P.
R.V.
Jolos
R.V.
H.A.
Weidenmüller
H.A.
Institut für Kernphysik, Universität zu Köln, 50937 Köln, Germany
Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia
Institut für Theoretische Physik, Justus-Liebig-Universität-Giessen Heinrich-Buff-Ring 16, D 35392 Giessen, Germany
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-01-29 15:06:12.231619
Copyright © 2002 Published by Elsevier Science B.V. All rights reserved.
oai:edoc.mpg.de:631042004-02-1037:452
InBook
Unordnung und Chaos in Quantensystemen
German
LEOPOLDINA 47
2002
343
355
Jahrbuch 2001 der Deutschen Akademie der Naturforscher Leopoldina
popular
published
notrev
H.A.
Weidenmüller
H.A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-10 09:26:00.142457
oai:edoc.mpg.de:631992004-12-3037:452
Article
Chaos in Atomkernen
German
2004
41
48
Physik Journal
3
popular
published
notrev
H. A.
Weidenmüller
H.A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005
2004-12-30 10:07:58.734092
oai:edoc.mpg.de:632012004-12-3037:452
Article
Persistent currents in n-fold twisted Moebius strips
English
2004-11-29
146
151
Europhysics Letters
1-2
333
expertsonly
published
notspecified
E. H. M.
Ferreira
E.H.M.
M. C.
Nemes
M.C.
M. D.
Sampaio
M.D.
H. A.
Weidenmüller
H.A.
UFMG, Dept Phys, ICEx
CP 702
BR-30161970 Belo Horizonte
MG
Brazil
UFMG, Dept Phys, ICEx
BR-30161970 Belo Horizonte
MG
Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005
2004-12-30 14:03:48.134153
oai:edoc.mpg.de:632212004-02-1137:452
Article
On the size of hadrons
English
2001
4351
4364
International Journal of Modern Physics A
Int. J. Mod. Phys. A
26
16
The form factor and the mean-square radius of the pion are calculated analytically from a parametrized form of a q (q) over bar wave function. The numerical wave function was obtained previously by solving numerically an eigenvalue equation for the pion in a particular model. The analytical formulas are of more general interest than just being valid for the pion and can be generalized to the case with unequal quark masses. Two different parametrizations are investigated. Because of the highly relativistic problem, noticeable deviations from a nonrelativistic formula are obtained.
expertsonly
published
joureview
H.C.
Pauli
H.C.
A.
Mukherjee
A.
Saha Institute of Nuclear Physics
Calcutta 700009
W Bengal
India
Univ Regensburg
D-93040 Regensburg
Germany
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-11 15:15:09.593656
WORLD SCIENTIFIC PUBL CO PTE LTD, JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE
oai:edoc.mpg.de:632242004-02-2637:452
Article
Power-law wave functions and generalized parton distributions for the pion
English
2003
1
19
073014
Physical Review D (Particles and Fields)
Phys. Rev. D
67
We propose a model for generalized parton distributions of the pion based on the power-law Ansatz for the effective light-cone wave function.
expertsonly
published
joureview
A.
Mukherjee
A.
I. V.
Musatov
I. V.
H. C.
Pauli
H. C.
A. V.
Radyushkin
A. V.
Universität Mainz, J. J. Becher Weg 45, D-55099, Mainz, Germany
Universität Regensburg, D-93040 Regensburg, Germany
Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064, India
Theory Group, Jefferson Lab, Newport News, Virginia 23606
Physics Department, Old Dominion University, Norfolk, Virginia 23529
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-02-26 14:52:10.645156
©2003 The American Physical Society
oai:edoc.mpg.de:632372004-02-1237:452
Article
On the form factor of physical mesons and their distribution function
English
2002
73
89
Nuclear Physics A
Nucl. Phys. A
1-2
705
This work addresses more to the technical rather than to the physical problem, how to calculate analytically the form factor F(Q), the associated mean-square radius <r<sup>2</sup>>, and the distribution function Φ(x,Q<sup>2</sup>) for a given light-cone wave function Ψ <sub>qqbar</sub>( x, kbar) of the pion. They turn out to be functions of only one dimensionless parameter, which is the ratio of the constituent quark mass and an effective Bohr momentum which measures the width of the wave function in momentum space. Both parameters are subject to change in the future, when the presently used solution for the over simplified -model will be replaced by something better. Their relation to and agreement with experiment is discussed in detail. The procedure can be generalized also to other hadrons.
expertsonly
published
joureview
H.C.
Pauli
H.C.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-12 10:25:21.69885
Copyright © 2002 Elsevier Science B.V. All rights reserved.
oai:edoc.mpg.de:632402004-02-1237:452
Article
Nonadiabatic controlled CNOT gate for the Kane solid-state quantum computer
English
2002
1
4
032303
Physical Review A (Atomic, Molecular, and Optical Physics)
Phys. Rev. A
65
The method of iterated resolvents is used to obtain an effective Hamiltonian for neighboring qubits in the Kane solid-state quantum computer. In contrast to the adiabatic gate processes inherent in the Kane proposal we show that free evolution of the qubit-qubit system, as generated by this effective Hamiltonian, combined with single-qubit operations, is sufficient to produce a controlled-NOT gate. Thus the usual set of universal gates can be obtained on the Kane quantum computer without the need for adiabatic switching of the controllable parameters as prescribed by Kane [Nature (London) 393, 133 (1998)]. Both the fidelity and the gate time of this nonadiabatic controlled-NOT gate are determined by numerical simulation.
expertsonly
published
joureview
C.
Wellard
C.
L. C. L.
Hollenberg
L. C. L.
H. C.
Pauli
H. C.
School of Physics, University of Melbourne, Melbourne 3010, Australia
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-12 10:57:14.540002
©2002 The American Physical Society
oai:edoc.mpg.de:632412004-02-1237:452
Article
Renormalization of an effective light-cone QCD-inspired theory for the pion and other mesons
English
2001
054007 -1
054007 - 13
Physical Review D (Particles and Fields)
Phys. Rev. D
64
The renormalization of the effective QCD Hamiltonian theory for the quark-antiquark channel is performed in terms of a renormalized or fixed-point Hamiltonian that leads to subtracted dynamical equations. The fixed-point Hamiltonian gives the renormalization conditions as well as the counterterms that render the theory finite. The approach is renormalization group invariant. The parameters of the renormalized effective QCD Hamiltonian come from the pion mass and radius for a given constituent quark mass. The 1s and excited 2s states of u-bar q are calculated as a function of the mass of the quark q being s, c, or b, and compared to the experimental values.
expertsonly
published
joureview
T.
Frederico
T.
H.C.
Pauli
H.C.
Dep. de Física, Instituto Tecnológico de Aeronáutica, Centro Técnico Aeroespacial, 12.228-900 São José dos Campos, São Paulo, Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-12 10:34:01.284941
©2001 The American Physical Society
oai:edoc.mpg.de:632432004-02-1237:452
Article
Splitting of the pi-rho spectrum in a renormalized light-cone QCD-inspired model
English
2002
054007-1
054007-6
Physical Review D (Particles and Fields)
Phys. Rev. D
66
We show that the splitting between the light pseudoscalar and vector meson states is due to the strong short-range attraction in the <sup>1</sup>S<sub>0</sub> sector which makes the pion and the kaon light particles. We use a light-cone QCD-inspired model of the mass squared operator with harmonic confinement and a Dirac-delta interaction. We apply a renormalization method to define the model, in which the pseudoscalar ground state mass fixes the renormalized strength of the Dirac-delta interaction
expertsonly
published
joureview
T.
Frederico
T.
H.C.
Pauli
H.C.
S.G.
Zhou
S.G.
Dep.de Física, Instituto Tecnológico de Aeronáutica, Centro Técnico Aeroespacial, 12.228-900 São José dos Campos, São Paulo, Brazil
School of Physics, Peking University, Beijing 100871, China
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-12 11:02:32.569615
©2002 The American Physical Society
oai:edoc.mpg.de:632472004-02-1337:452
Article
Experimental tests of non-perturbative pion wave functions
English
2003
329
333
European Physical Journal C
Eur. Phys. J. C
28
We use the transverse-momentum dependence of the cross section for the diffractive dissociation of high energy pions to two jets to study some non-perturbative light-cone wave functions of the pion. We compare the predictions for this distribution by Gaussian and Coulomb wave functions as well as the wave function derived from a solution of the light-cone Hamiltonian in the singlet model. We conclude that this experimentally measured information provides a powerful tool for these studies.
expertsonly
published
joureview
D.
Ashery
D.
H.C.
Pauli
H.C.
School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Israel
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-02-13 08:39:21.881848
© Società Italiana di Fisica, Springer-Verlag 2003
oai:edoc.mpg.de:632612004-02-1337:452
Conference-Paper
Renormalization of an effective model Hamiltonian by a counterterm
English
Published by Elsevier Science B.V
239
241
Nuclear Physics B - Proceedings Supplements
Light Cone Physics: Particles and Strings
Trento, Italy
2001-09-03
2001-09-11
6. Effective Hamiltonians
An ill-defined integral equation for modeling the mass-spectrum of mesons is regulated with an additional but unphysical parameter. This parameter dependance is removed by renormalization. Illustrative graphical examples are given.
expertsonly
published
joureview
M.
Frewer
M.
T.
Frederico
T.
H.C.
Pauli
H.C.
Dep. de Física, Instituto Tecnológico de Aeronáutica, Centro Técnico Aeroespacial, 12.228-900, S. José dos Campos, SP, Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-13 09:14:39.554143
Copyright © 2002 Published by Elsevier Science B.V.
oai:edoc.mpg.de:632622004-02-1337:452
Conference-Paper
Renormalized QCD-inspired model for the pion and mesons
English
Published by Elsevier Science B.V
2002
234
238
Nuclear Physics B - Proceedings Supplements
Light-Cone Physics: Particles and Strings
Trento, Italy
2001-09-03
2001-09-11
6. Effective Hamiltonians
We apply the subtraction method to an effective QCD-inspired model, which includes the Coulomb plus a zero-range hyperfine interactions, to define a renormalized Hamiltonian for mesons. The spectrum of the renormalized Hamiltonian agrees with the one obtained with a smeared hyperfine interaction. The masses of the low-lying pseudoscalar and vector mesons are reasonably described within the model.
expertsonly
published
joureview
T.
Frederico
T>
M.
Frewer
M.
H.C.
Pauli
H.C.
Dep. de Física, Instituto Tecnológico de Aeronáutica, Centro Técnico Aeroespacial, 12.228-900, S. José dos Campos, SP, Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-13 09:18:42.630194
Copyright © 2002 Published by Elsevier Science B.V.
oai:edoc.mpg.de:632632004-02-1337:452
Conference-Paper
On helicity and spin on the light cone
English
Published by Elsevier Science B.V.
2002
251
255
Nuclear Physics B - Proceedings Supplements
Light-Cone Physics: Particles and Strings
2001-09-03
2001-09-11
6. Effective Hamiltonians
Starting from a one--body front--form equation with Lepage-Brodsky spinors we show, with a fair amount of new technology, how an integral equation in standard momentum space with Bjørken-Drell spinors can be obtained. The integral equation decouples for singlets and triplets.
expertsonly
published
joureview
A.
Krassnigg
A.
H.C.
Pauli
H.C.
Institut für Theoretische Physik, Karl-Franzens-Universität, A-8010, Graz, Austria
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-02-13 09:24:15.459967
Copyright © 2002 Published by Elsevier Science B.V.
oai:edoc.mpg.de:632642010-10-0237:452
Article
Bayesian analysis of level-spacing distributions for chaotic systems with broken symmetry
English
2002
056221-1
056221-9
Physical Review e (Statistical, Nonlinear, and Soft Matter Physics)
Phys. Rev. E 65
65
Bayesian inference is applied to the nearest-neighbor and next-nearest-neighbor spacing distributions of levels of coupled superconducting microwave billiards. The weakly coupled resonators are equivalent to a quantum system with a partially broken symmetry. The coupling parameters are obtained with help from Bayes's theorem. This procedure does not require the introduction of a set of bins. The results are more accurate than those obtained from other bin-independent procedures.
Automatic journal name synchronization
expertsonly
published
joureview
A. Y.
Abul-Magd
A. Y.
C.
Dembowski
C.
H. L.
Harney
H. L.
M. H.
Simbel
M. H.
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2010-10-02 20:15:05.483143
©2002 The American Physical Society
oai:edoc.mpg.de:632662004-02-2437:452
Article
Observation of a Chiral State in a Microwave Cavity
English
2003
034101
034101
Physical Review Letters
Phys. Rev. Lett. 90
90
A microwave experiment has been realized to measure the phase difference of the oscillating electric field at two points inside the cavity. The technique has been applied to a dissipative resonator which exhibits a singularity-called exceptional point-in its eigenvalue and eigenvector spectrum. At the singularity, two modes coalesce with a phase difference of π/2. We conclude that the state excited at the singularity has a definitive chirality.
expertsonly
published
joureview
C.
Dembowski
C.
B.
Dietz
B.
H.-D.
Gräf
H.-D.
H. L.
Harney
H. L.
A.
Heine
A.
W. D.
Heiss
W. D.
A.
Richter
A.
Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany
Department of Physics, University of Stellenbosch, 7602 Matieland, South Africa
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-02-24 09:25:00.173744
©2003 The American Physical Society
oai:edoc.mpg.de:632782004-12-3037:452
Article
Time Reversal and Exceptional Points
English
2004-06
429
432
The European Physical Journal D
Eur. Phys. J D
3
29
Eigenvectors of decaying quantum systems are studied at exceptional points of the Hamiltonian. Special attention is paid to the properties of the system under time reversal symmetry breaking.
At the exceptional point the chiral character of the system ---found for time reversal symmetry --- generically persists. It is,however, no longer circular but rather elliptic.
expertsonly
published
notspecified
http://edoc.mpg.de/get.epl?fid=3650&did=63278&ver=0
H. L.
Harney
H.L.
W. D.
Heiss
W.D.
Department of Physics, University of Stellenbosch,
7602 Matieland, South Africa
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2004-12-30 13:53:00.667092
oai:edoc.mpg.de:632832004-02-2437:452
Article
Statistics of 2<sup>+</sup> levels in even-even nuclei
English
2004
278
284
Physics Letters B
Phys. Lett. B
3-4
579
Using all the available empirical information, we analyze the spacing distributions of low-lying 2<sup>+</sup> levels of even-even nuclei. To obtain statistically relevant samples, the nuclei are grouped into classes defined by the ratio R<sub>4/2</sub> of the excitation energies of the first 4<sup>+</sup> and 2<sup>+</sup> levels. This ratio serves as a measure of collectivity in nuclei. With the help of Bayesian inference, we determine the chaoticity parameter for each class. This parameter is found to vary strongly with R<sub>4/2</sub> and takes particularly small values in nuclei that have one of the dynamical symmetries of the interacting boson model.
expertsonly
published
joureview
A. Y.
Abul-Magd
A. Y.
H. L.
Harney
H. L.
H. A.
Weidenmüller
H. A.
Faculty of Science, Zagazig University, Zagazig, Egypt
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2005
2004-02-24 09:24:00.295595
Copyright © 2003 Published by Elsevier Science B.V.
oai:edoc.mpg.de:632852004-12-3037:452
Article
Encircling an Exceptional Point
English
2004-05-24
056216
Physical Review E
Phys. Rev. E
69
We calculate analytically the geometric phases that
the eigenvectors of a parametric dissipative two-state system described by a
complex symmetric Hamiltonian pick up
when an exceptional point (EP) is encircled. An EP is a parameter
setting where the two eigenvalues and the corresponding eigenvectors of
the Hamiltonian coalesce. We show that it can be
encircled on a path along which the eigenvectors remain approximately
real and discuss a microwave cavity experiment, where such an encircling of
an EP was realized. Since the wavefunctions remain
approximately real, they could be reconstructed
from the nodal lines of the recorded spatial intensity distributions
of the electric fields inside the resonator. We measured the geometric
phases that occur when an EP is encircled four times and thus confirmed
that for our system an EP is a branch point of fourth order.
expertsonly
published
joureview
http://edoc.mpg.de/get.epl?fid=3637&did=63285&ver=0
C.
Dembowski
C.
B.
Dietz
B.
H. D.
Gräf
H.D.
H. L.
Harney
H.L.
A.
Heine
A.
W. D.
Heiss
W.D.
A.
Richter
A.
Institut für Kernphysik, Technische Universität
Darmstadt, D-64289 Darmstadt, Germany
Department of Physics, University of Stellenbosch, 7602
Matieland, South Africa
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2004-12-30 10:02:06.339821
oai:edoc.mpg.de:632882004-06-1137:452
Book
Bayesian Inference : Parameter Estimation and Decisions
English
Springer
New York [u.a.]
2003
The book provides a generalization of Gaussian error intervals ti situations where the data follow non-Gaussian distributions. This usually occurs in frontier science, where the observed parameter is just above background or the histogram of multiparametric data contains empty bins. Then the validity of a theory cannot be decided by the chi-squared-criterion, but this long-
expertsonly
263 S.
published
H. L.
Harney
Hanns Ludwig
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004
2004-06-11 14:21:04.406479
Springer Verlag
oai:edoc.mpg.de:633402004-03-0537:452
Article
Statistics in 2<sup>+</sup> levels in even-even nuclei
English
2004
278
284
Physics Letters B
579
expertsonly
published
joureview
A. Y.
Abul-Magd
A. Y.
H.L.
Harney
H.L.
M.H.
Simbel
M.H.
H.A.
Weidenmüller
H.A.
MPI für Kernphysik
Guest Groups and Emeriti
Theory (H.A. Weidenmüller)
2004-03-05 10:18:31.340092
Elsevier
oai:edoc.mpg.de:2076982005-02-0937:452
Article
Observation of a Chiral State in a Microwave Cavitiy
2003-01-23
1
4
034101
Physical Review Letters
Phys. Rev. Lett.
3
90
A microwave experiment has been realized to measure the phase difference of the oscillating electric field at two points inside the cavity. The technique has been applied to a dissipative resonator which exhibits a singularity—called exceptional point—in its eigenvalue and eigenvector spectrum. At the singularity, two modes coalesce with a phase difference of /2. We conclude that the state excited at the singularity has a definitive chirality.
published
notspecified
C.
Dembowski
C.
B.
Dietz
B.
H.-D.
Gräf
H.-D.
H. L.
Harney
H. L.
A.
Heine
A.
W. D.
Heiss
W. D.
A.
Richter
A.
10.1103/PhysRevLett.90.034101
Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt
Department of Physics, University of Stellenbosch, 7602 Matieland, Südafrika
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005-02-09 10:32:59.785105
©2003 The American Physical Society
oai:edoc.mpg.de:2077092005-02-0837:452
Book
Bayesian inference : parameter estimation and decisions ; with numerous examples, and 79 problems with solutions
English
Springer Verlag
Heidelberg
2003
expertsonly
XIII, 263 S. : graph. Darst.
published
http://edoc.mpg.de/get.epl?fid=9979&did=207709&ver=0
H. L.
Harney
H. L.
3-540-00397-5
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2004
2005-02-08 13:12:59.175288
oai:edoc.mpg.de:2077102005-02-0937:452
Conference-Paper
Regularity and chaos in low-lying 2<sup>+</sup> states of even-even nuclei
English
World Scientific
Singapore
2004
398
405
Symmetries in Nuclear Structure
Erice, Italy
2003-03-23
2003-03-30
Proceedings of the Highly Specialized Seminar on Symmetries in Nuclear Structure
Andrea Vitturi and Richard F. Casten
expertsonly
XIII, 480 S. : Ill., graph. Darst.
published
notspecified
A. Y.
Abul-Magd
A. Y.
H. L.
Harney
H. L.
M. H.
Simbel
M. H.
H. A.
Weidenmüller
H. A.
981-238-812-5
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005
2005-02-09 13:24:18.811133
oai:edoc.mpg.de:2077922005-07-0837:452
Article
Encircling an exceptional point
2004-05-24
1
7
056216
Physical Review E
Phys. Rev. E
69
We calculate analytically the geometric phases that the eigenvectors of a parametric dissipative two-state system described by a complex symmetric Hamiltonian pick up when an exceptional point (EP) is encircled. An EP is a parameter setting where the two eigenvalues and the corresponding eigenvectors of the Hamiltonian coalesce. We show that it can be encircled on a path along which the eigenvectors remain approximately real and discuss a microwave cavity experiment, where such an encircling of an EP was realized. Since the wave functions remain approximately real, they could be reconstructed from the nodal lines of the recorded spatial intensity distributions of the electric fields inside the resonator. We measured the geometric phases that occur when an EP is encircled four times and thus confirmed that for our system an EP is a branch point of fourth order.
expertsonly
published
notspecified
C.
Dembowski
C.
B.
Dietz
B.
H.-D.
Gräf
H.-D.
H. L.
Harney
H. L.
A.
Heine
A.
W. D.
Heiss
W. D.
A.
Richter
A.
10.1103/PhysRevE.69.056216
Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt
Department of Physics, University of Stellenbosch, 7602 Matieland, Südafrika
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005
2005-07-08 09:46:52.092306
©2004 The American Physical Society
oai:edoc.mpg.de:2078042005-02-0937:452
Article
Power-law wave functions and generalized parton distributions for the pion
2003-04-23
1
19
073014
Physical Review D
Phys. Rev. D
67
We propose a model for generalized parton distributions of the pion based on the power-law Ansatz for the effective light-cone wave function.
published
notspecified
A.
Mukherjee
A.
I. V.
Musatov
I. V.
H. C.
Pauli
H. C.
A. V.
Radyushkin
A. V.
10.1103/PhysRevD.67.073014
Universität Mainz, J. J. Becher Weg 45, D-55099, Mainz, Germany
Universität Regensburg, D-93040 Regensburg, Germany
Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064, India
Theory Group, Jefferson Lab, Newport News, Virginia 23606
Physics Department, Old Dominion University, Norfolk, Virginia 23529
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005-02-09 10:26:04.238513
©2003 The American Physical Society
oai:edoc.mpg.de:2078052005-07-0837:452
Article
S wave meson spectra from the light cone harmonic oscillator model with a consistent hyperfine interaction
2004-08-02
983
988
Journal of Physics G-Nuclear & Particle Physics
J. Phys. G
9
30
We use a light cone harmonic oscillator model to study S wave meson spectra, namely, the pseudoscalar and vector mesons. The model Hamiltonian is a mass squared operator consisting of a central potential (a harmonic oscillator potential) from which a hyperfine interaction is derived. The hyperfine interaction is responsible for the splitting in the pseudoscalar–vector spectra. With four parameters for the masses of up/down, strange, charm and bottom quarks, two for the harmonic oscillator potential and one for the hyperfine interaction, the model presents a reasonably good agreement with the data.
expertsonly
published
notspecified
S. G.
Zhou
S. G.
H. C.
Pauli
H. C.
10.1088/0954-3899/30/9/003
Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China
School of Physics, Peking University, Beijing 100871, People's Republic of China
Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000, People's Republic of China
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005
2005-07-08 09:46:19.287047
IOP PUBLISHING LTD
oai:edoc.mpg.de:2078092005-02-0937:452
Article
Experimental tests of non-perturbative pion wave functions
English
2003-04-14
329
333
European Physical Journal C
Eur. Phys. J. C
3
28
We use the transverse-momentum dependence of the cross section for the diffractive dissociation of high energy pions to two jets to study some non-perturbative light-cone wave functions of the pion. We compare the predictions for this distribution by Gaussian and Coulomb wave functions as well as the wave function derived from a solution of the light-cone Hamiltonian in the singlet model. We conclude that this experimentally measured information provides a powerful tool for these studies.
expertsonly
published
notspecified
D.
Ashery
D.
H. C.
Pauli
H. C.
10.1140/epjc/s2003-01187-3
School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Israel
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2004
2005-02-09 10:21:15.582068
© Società Italiana di Fisica, Springer-Verlag 2003
oai:edoc.mpg.de:2078102005-07-0837:452
Article
Succesful renormalization of a QCD-inspired Hamiltonian
English
2004-02
15
22
European Physical Journal A
Eur. Phys. J. A
Suppl. 1
19
expertsonly
published
notspecified
H. C.
Pauli
H. C.
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2005
2005-07-08 09:45:47.321304
oai:edoc.mpg.de:2857062007-09-1837:452
Article
Nuclear masses, chaos, and the residual interaction
English
2006-06-01
48
52
Physics Letters B
Phys. Lett. B
1-2
637
We interpret the discrepancy between semiempirical nuclear mass formulas and actual nuclear masses in terms of the residual interaction. We show that correlations exist among all binding energies and all separation energies throughout the valley of stability. We relate our approach to chaotic motion in nuclei.
expertsonly
published
notspecified
A.
Molinari
A.
H. A.
Weidenmüller
Hans A.
10.1016/j.physletb.2006.04.025
Dipartimento di Fisica Teorica dell'Universita di Torino, and Instituto Nationale di Fisica Nucleare, Sezione di Torino, Torino, Italy
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2007
2007-09-18 13:34:57.304712
© 2006 Elsevier B.V.
oai:edoc.mpg.de:2857082007-09-1937:452
Article
Statistical analysis of composite spectra
English
2006-03-01
560
580
Annals of Physics
3
321
We consider nearest-neighbor spacing distributions of composite ensembles of levels. These are obtained by combining independently unfolded sequences of levels containing only few levels each. Two problems arise in the spectral analysis of such data. One problem lies in fitting the nearest-neighbor spacing distribution to the histogram of level spacings obtained from the data. We show that the method of Bayesian inference is superior to this procedure. The second problem occurs when one unfolds such short sequences. We show that the unfolding procedure generically leads to an overestimate of the chaoticity parameter. This trend is absent in the presence of long-range level correlations. Thus, composite ensembles of levels from a system with long-range spectral stiffness yield reliable information about the chaotic behavior of the system.
expertsonly
published
notspecified
A. Y.
Abul-Magd
A. Y.
H.-L.
Harney
Hanns-Ludwig
M. H.
Simbel
M. H.
H. A.
Weidenmüller
Hans A.
10.1016/j.aop.2005.04.005
Faculty of Science, Zagazig University, Zagazig, Egypt
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2007
2007-09-19 10:56:32.803686
© 2005 Elsevier Inc.
oai:edoc.mpg.de:2857122007-09-1937:452
Article
Two-body random ensemble in nuclei
English
2006-01-26
014311
Physical Review C
Phys. Rev. C
73
Combining analytical and numerical methods, we investigate properties of the two-body random ensemble (TBRE). We compare the TBRE with the Gaussian orthogonal ensemble of random matrices. Using the geometric properties of the nuclear shell model, we discuss the information content of nuclear spectra and gain insight in the difficulties encountered when fitting the effective interaction. We exhibit the existence of correlations between spectral widths pertaining to different quantum numbers. Using these results, we deduce the preponderance of zero-spin ground states in the TBRE. We demonstrate the existence of correlations between spectra with different quantum numbers and/or in different nuclei.
expertsonly
published
joureview
T.
Papenbrock
T.
H. A.
Weidenmüller
Hans A.
10.1103/PhysRevC.73.014311
Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2007
2007-09-19 13:43:27.385885
©2006 The American Physical Society
oai:edoc.mpg.de:2857292006-08-1837:452
Article
Origin of chaos in the spherical nuclear shell model: Role of symmetries
English
2005-08-22
422
438
Nuclear Physics A
Nucl. Phys. A
3-4
757
To elucidate the mechanism by which chaos is generated in the shell model, we compare three random-matrix ensembles: the Gaussian orthogonal ensemble, French's two-body embedded ensemble, and the two-body random ensemble (TBRE) of the shell model. Of these, the last two take account of the two-body nature of the residual interaction, and only the last, of the existence of conserved quantum numbers like spin, isospin, and parity. While the number of independent random variables decreases drastically as we follow this sequence, the complexity of the (fixed) matrices which support the random variables, increases even more. In that sense we can say that in the TBRE, chaos is largely due to the existence of (an incomplete set of) symmetries.
expertsonly
published
notspecified
T.
Papenbrock
T.
H. A.
Weidenmüller
Hans A.
10.1016/j.nuclphysa.2005.04.018
Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2006-08-18 09:37:32.58361
© 2005 Elsevier B.V.
oai:edoc.mpg.de:2857312006-08-1837:452
Article
Disordered mesoscopic systems with interactions: Induced two-body ensembles and the Hartree-Fock approach
English
2005-07-08
045318
Physical Review A
Phys. Rev. A
72
We introduce a generic approach to study interaction effects in diffusive or chaotic quantum dots in the Coulomb blockade regime. The randomness of the single-particle wave functions induces randomness in the two-body interaction matrix elements. We classify the possible induced two-body ensembles, both in the presence and absence of spin degrees of freedom. The ensembles depend on the underlying space-time symmetries as well as on features of the two-body interaction. Confining ourselves to spinless electrons, we then use the Hartree-Fock (HF) approximation to calculate HF single-particle energies and HF wave functions for many realizations of the ensemble. We study the statistical properties of the resulting one-body HF ensemble for a fixed number of electrons. In particular, we determine the statistics of the interaction matrix elements in the HF basis, of the HF single-particle energies (including the HF gap between the last occupied and the first empty HF level), and of the HF single-particle wave functions. We also study the addition of electrons, and in particular the distribution of the distance between successive conductance peaks and of the conductance peak heights.
expertsonly
published
joureview
Y.
Alhassid
Y.
H. A.
Weidenmüller
Hans A.
A.
Wobst
A.
10.1103/PhysRevB.72.045318
Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Connecticut 06520, USA
Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2006-08-18 09:36:18.751955
Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany
oai:edoc.mpg.de:2857322006-08-1837:452
Article
Parametric level correlations in random-matrix models
English
2005-05-06
S1881
S1887
Journal of Physics: Condensed Matter
J. Phys.: Condens. Matter
20
17
We show that parametric level correlations in random-matrix theories are closely related to a breaking of the symmetry between the advanced and the retarded Green functions. The form of the parametric level correlation function is the same as for the disordered case considered earlier by Simons and Altshuler and is given by the graded trace of the commutator of the saddle-point solution with the particular matrix that describes the symmetry breaking in the actual case of interest. The strength factor differs from the case of disorder. It is determined solely by the Goldstone mode. It is essentially given by the number of levels that are strongly mixed as the external parameter changes. The factor can easily be estimated in applications.
expertsonly
published
notspecified
H. A.
Weidenmüller
Hans A.
10.1088/0953-8984/17/20/015
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2006-08-18 09:34:58.779804
© Institute of Physics and IOP Publishing Limited 2006
oai:edoc.mpg.de:2857332006-08-1837:452
Article
Kondo temperature for a quantum dot in an Aharonov-Bohm ring
English
2005-03-18
121309
Physical Review B
Phys. Rev. B
71
We study the Kondo temperature of a quantum dot embedded into one arm of an Aharonov-Bohm interferometer. The topology of a disordered or chaotic Aharonov-Bohm ring leads to a stochastic term in the scaling equation and in the renormalization procedure. As a result, the Kondo temperature displays significant fluctuations as a function of magnetic flux.
expertsonly
published
joureview
C. H.
Lewenkopf
C. H.
H. A.
Weidenmüller
Hans A.
10.1103/PhysRevB.71.121309
Instituto de Física, UERJ, R. São Francisco Xavier 524, 20550-900 Rio de Janeiro, Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2006-08-18 09:33:34.551825
©2005 The American Physical Society
oai:edoc.mpg.de:2857342006-08-1837:452
Article
Persistent currents in n-fold twisted Moebius strips
English
2004-11-29
146
151
Physics Letters A
Phys. Lett. A
1-2
333
We investigate the influence of the topology on generic features of the persistent current in n-fold twisted Moebius strips formed of quasi one-dimensional mesoscopic rings, both for free electrons and in the weakly disordered regime. We find that there is no generic difference between the persistent current for untwisted rings and for Moebius strips with an arbitrary number of twists.
expertsonly
published
notspecified
E. H.
Martins Ferreira
E. H.
M. C.
Nemes
M. C.
M. D.
Sampaio
M. D.
H. A.
Weidenmüller
Hans A.
10.1016/j.physleta.2004.10.026
Department of Physics, ICEx, UFMG, CP 702, 30.161-970 Belo Horizonte, MG, Brazil
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2006-08-18 09:31:51.364579
© 2004 Elsevier B.V.
oai:edoc.mpg.de:2857352006-08-1837:452
Article
Statistical fluctuations of ground-state energies and binding energies in nuclei
English
2004-11-11
119
124
Physics Letters B
Phys. Lett. B
3-4
601
The statistical fluctuations of the ground-state energy and of the binding energy of nuclei are investigated using both perturbation theory and supersymmetry. The fluctuations are induced by the experimentally observed stochastic behavior of levels in the vicinity of neutron threshold. The results are compared with a recent analysis of binding-energy fluctuations by Bohigas and Leboeuf, and with theoretical work by Feshbach et al.
expertsonly
published
notspecified
A.
Molinari
A.
H. A.
Weidenmüller
Hans A.
10.1016/j.physletb.2004.09.042
Dipartimento di Fisica Teorica dell'Università di Torino and Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via P. Giuria 1, I-10125 Torino, Italy
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2006-08-18 09:30:17.471169
© 2004 Elsevier B.V.
oai:edoc.mpg.de:2857362006-08-1837:452
Article
Distribution of Spectral Widths and Preponderance of Spin-0 Ground States in Nuclei
English
2004-09-23
132503
Physical Review Letters
Phys. Rev. Lett.
93
We use a single j-shell model with random two-body interactions to derive closed expressions for the distribution of and the correlations between spectral widths of different spins. This task is facilitated by introducing two-body operators whose squared spectral widths sum up to the squared spectral width of the random Hamiltonian. The spin-0 width is characterized by a relatively large average value and small fluctuations, while the width of maximum spin has the largest average and the largest fluctuations. The approximate proportionality between widths and spectral radii explains the preponderance of spin-0 ground states.
expertsonly
published
joureview
T.
Papenbrock
T.
H. A.
Weidenmüller
Hans A.
10.1103/PhysRevLett.93.132503
Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
MPI für Kernphysik
Guest Groups and Emeriti
Theory of Chaos, Fields and Statistical Inference (H.A. Weidenmüller et al.)
2006-08-18 09:28:29.233605
©2004 The American Physical Society
oai:edoc.mpg.de:3416082010-09-2937:452
Article
Interaction of regular and chaotic states
English
2007-10
2446
2468
Annals of Physics
Ann. Phys.
10
322
expertsonly
published
joureview
A.
De Pace
A.
A.
Molinari
A.
H. A.
Weidenmüller
Hans A.
000249994100008
0003-4916
Univ Turin, Dipartimento Fis Teor, I-10125 Turin, Italy.; Ist Nazl Fis Nucl, Sez Torino, I-10125 Turin, Italy.; Max Planck Inst Kernphys, D-69029 Heidelberg, Germany.
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2008
2010-09-29 11:00:45.773311
oai:edoc.mpg.de:3416122010-09-2937:452
Article
Colloquium: Random matrices and chaos in nuclear spectra
English
2007-07
997
1013
Reviews of Modern Physics
Rev. Mod. Phys.
3
79
notspecified
published
joureview
T.
Papenbrock
T.
H. A.
Weidenmüller
Hans A.
000248867000007
0034-6861
Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA.; Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA.
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2008
2010-09-29 11:01:32.935688
oai:edoc.mpg.de:3416172008-03-1537:452
Article
Induced time-reversal symmetry breaking observed in microwave billiards
English
2007-02-16
074103
Physical Review Letters
Phys. Rev. Lett.
7
98
Automatic journal name synchronization
expertsonly
published
joureview
B.
Dietz
B.
T.
Friedrich
T.
H. L.
Harney
H. L.
M.
Miski-Oglu
M.
A.
Richter
A.
F.
Schafer
F.
H. A.
Weidenmüller
H. A.
000244250300029
0031-9007
Tech Univ Darmstadt, Inst Kernphys, D-64289 Darmstadt, Germany.
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2008
2008-03-15 20:08:36.804652
oai:edoc.mpg.de:3944792008-11-2937:452
Article
Scrambling of Hartree-Fock levels as a universal Brownian-motion process
English
2007-11
193110
Physical Review B
Phys. Rev. B
19
76
Automatic journal name synchronization
expertsonly
published
joureview
Y.
Alhassid
Y.
H. A.
Weidenmüller
H. A.
A.
Wobst
A.
000251326800010
1098-0121
Yale Univ, Ctr Theoret Phys, Sloane Phys Lab, New Haven, CT 06520 USA.;[Wobst, A.] Univ Augsburg, Inst Phys, D-86135 Augsburg, Germany.
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2008-11-29 20:15:04.075729
oai:edoc.mpg.de:3944802011-05-1337:452
Conference-Paper
Statistical theory of compound-nuclear reactions
English
American Institute of Physics
Melville, NY
2008
3
9
1005
International Workshop on Compound-Nuclear Reactions and Related Topic - CNR* 2007
Yosemite National Park, California
2007-10-22
2007-10-27
COMPOUND-NUCLEAR REACTIONS AND RELATED TOPICS: Proceedings of the 2007 International Workshop on Compound-Nuclear Reactions and Related Topics - CNR* 2007
AIP Conference Proceedings
expertsonly
260 S.
published
notspecified
H. A.
Weidenmüller
H. A.
000255660900001
0094-243X
MPI für Kernphysik
Guest Groups and Emeriti
H.A. Weidenmüller
2009
2011-05-13 10:52:16.159886
ResultSet_4uBYZK9BtlM_range_100-112