195 research outputs found
Comment on "Quenches in quantum many-body systems: One-dimensional Bose-Hubbard model reexamined" [arXiv:0810.3720]
In a recent paper Roux [Phys. Rev. A 79, 021608(R) (2009), arXiv:0810.3720]
argued that thermalization in a Bose-Hubbard system, after a quench, follows
from the approximate Boltzmann distribution of the overlap between the initial
state and the eigenstates of the final Hamiltonian. We show here that the
distribution of the overlaps is in general not related to the canonical (or
microcanonical) distribution and, hence, it cannot explain why thermalization
occurs in quantum systems.Comment: 2 pages, 1 figure, as publishe
Breakdown of thermalization in finite one-dimensional systems
We use quantum quenches to study the dynamics and thermalization of hardcore
bosons in finite one-dimensional lattices. We perform exact diagonalizations
and find that, far away from integrability, few-body observables thermalize. We
then study the breakdown of thermalization as one approaches an integrable
point. This is found to be a smooth process in which the predictions of
standard statistical mechanics continuously worsen as the system moves toward
integrability. We establish a direct connection between the presence or absence
of thermalization and the validity or failure of the eigenstate thermalization
hypothesis, respectively.Comment: 9 pages, 13 figures, as publishe
Effect of particle statistics in strongly correlated two-dimensional Hubbard models
We study the onset of particle statistics effects as the temperature is
lowered in strongly correlated two-dimensional Hubbard models. We utilize
numerical linked-cluster expansions and focus on the properties of interacting
lattice fermions and two-component hard-core bosons. In the weak-coupling
regime, where the ground state of the bosonic system is a superfluid, the
thermodynamic properties of the two systems at half filling exhibit very large
differences even at high temperatures. In the strong-coupling regime, where the
low-temperature behavior is governed by a Mott insulator for either particle
statistics, the agreement between the thermodynamic properties of both systems
extends to regions where the antiferromagnetic (iso)spin correlations are
exponentially large. We analyze how particle statistics affects adiabatic
cooling in those systems.Comment: 9 pages, 8 figure
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