Berlin 2024 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 35: Poster: Quantum Dynamics and Many-body Systems
DY 35.8: Poster
Wednesday, March 20, 2024, 15:00–18:00, Poster D
Thermalization of locally perturbed many-body quantum systems — Peter Reimann1, •Patrick Vorndamme1, and Lennart Dabelow2 — 1Universität Bielefeld — 2Queen Mary University, London
Deriving conditions under which a macroscopic system thermalizes directly from the underlying quantum many-body dynamics of its microscopic constituents is a long-standing challenge in theoretical physics. The well-known eigenstate thermalization hypothesis (ETH) is presumed to be a key mechanism, but has defied rigorous verification for generic systems thus far. A weaker variant (weak ETH), by contrast, is provably true for a large variety of systems, including even many integrable models, but its implications with respect to the problem of thermalization are still largely unexplored. Here we analytically demonstrate that systems satisfying the weak ETH exhibit thermalization for two very natural classes of far-from-equilibrium initial conditions: the overwhelming majority of all pure states with a preset nonequilibrium expectation value of some given local observable, and the Gibbs states of a Hamiltonian which subsequently is subject to a quantum quench in the form of a sudden change of some local system properties. As numerical example we show our findings for the (integrable) transverse-field Ising model (TFIM).
Keywords: thermalization; ETH; integrable; TFIM; perturbation