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Statistical mechanics of combinatorial optimization problems with site disorder

David S. Dean 1, David Lancaster 2, Satya. N. Majumdar 3 Physical Review E: Statistical, Nonlinear, and Soft Matter Physics 72 (2005) 026125 We study the statistical mechanics of a class of problems whose phase space is the set of permutations of an ensemble of quenched random positions. Specific examples analyzed are the finite temperature traveling salesman problem on several different domains […]

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Spin waves in a one-dimensional spinor Bose gas

J. N. Fuchs 1, D. M. Gangardt 2, T. Keilmann 3, G. V. Shlyapnikov 2, 4 Physical Review Letters 95 (2005) 150402 We study a one-dimensional (iso)spin 1/2 Bose gas with repulsive delta-function interaction by the Bethe Ansatz method and discuss the excitations above the polarized ground state. In addition to phonons the system features spin waves with a quadratic dispersion. We compute analytically

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Spatial correlation functions in 3-d Ising spin glasses

Cirano De Dominicis 1, Irene Giardina 2, Enzo Marinari 3, Olivier C. Martin 4, Francesco Zuliani 4 Physical Review B 72 (2005) 014443 We investigate spin-spin correlation functions in the low temperature phase of spin-glasses. With the replica field theory formalism, we examine in detail their infrared (long distance) behavior. In particular we identify a longitudinal mode that remains massive in the infinite volume limit.

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Spanning forests and the q-state Potts model in the limit q \\to 0

Jesper Lykke Jacobsen 1, Jesus Salas 2, Alan D. Sokal 3 Journal of Statistical Physics 119 (2005) 1153-1281 We study the q-state Potts model with nearest-neighbor coupling v=e^{\\beta J}-1 in the limit q,v \\to 0 with the ratio w = v/q held fixed. Combinatorially, this limit gives rise to the generating polynomial of spanning forests; physically, it provides information about the

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Scrambling and Gate Effects in Realistic Quantum Dots

Hong Jiang 1, Denis Ullmo 2, 3, Weitao Yang 1, Harold U. Baranger 2 Physical Review B 71 (2005) 085313 We evaluate the magnitude of two important mesoscopic effects using a realistic model of typical quantum dots. « Scrambling\’\’ and « gate effect\’\’ are defined as the change in the single-particle spectrum due to added electrons or gate-induced shape deformation, respectively. These two effects are investigated

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Scattering properties of weakly bound dimers of fermionic atoms

D. S. Petrov 1, 2, 3, C. Salomon 4, G. V. Shlyapnikov 2, 3, 5, 6 Physical Review A: Atomic, Molecular and Optical Physics 71 (2005) 012708 We consider weakly bound diatomic molecules (dimers) formed in a two-component atomic Fermi gas with a large positive scattering length for the interspecies interaction. We develop a theoretical approach for calculating atom-dimer and dimer-dimer elastic scattering and for analyzing

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