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TT: Fachverband Tiefe Temperaturen

TT 32: MLT: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ... 2

TT 32.2: Vortrag

Donnerstag, 25. März 2010, 14:15–14:30, H18

Generalized Gibbs ensemble prediction of prethermalization plateaus in nearly integrable systems — •Marcus Kollar¹, F. Alexander Wolf¹, and Martin Eckstein² — ¹Theoretische Physik III, Universität Augsburg, 86135 Augsburg — ²Theoretische Physik, ETH Zürich, 8093 Zürich, Schweiz

A quantum many-body system which is prepared in the ground state of an integrable Hamiltonian will not directly thermalize after a sudden small parameter change away from integrability. Instead, it first reaches a quasistable prethermalized state, which can be related to the perturbative ground state of the Hamiltonian after the quench [1]. We show that under certain conditions such prethermalization plateaus are predicted correctly by generalized Gibbs ensembles, which are the appropriate extension of standard statistical mechanics in the presence of many constants of motion. As a consequence, the relaxation behaviors of integrable and nearly integrable systems are continuously connected and described by the same statistical theory. For example, our result applies to the prethermalization plateau of the fermionic momentum distribution that is observed after a quench from zero to small Hubbard interaction [1,2].
M. Moeckel and S. Kehrein, Ann. Phys. 324, 2146 (2009).
M. Eckstein, M. Kollar, and P. Werner, Phys. Rev. Lett. 103, 056403 (2009); arXiv:0910.5674.