Sep 17 – 21, 2022
Faculty of Physics, Astronomy and Applied Computer Science; Jagiellonian University
Europe/Warsaw timezone
Registration and Abstract submission are CLOSED

To thermalize or not to thermalize, that is the question

Sep 18, 2022, 3:00 PM
45m
Faculty of Physics, Astronomy and Applied Computer Science; Jagiellonian University

Faculty of Physics, Astronomy and Applied Computer Science; Jagiellonian University

Łojasiewicza 11, 30-348 Kraków, Poland
Invited talk Sunday session

Speaker

Maciej Lewenstein (ICFO)

Description

In the first part of my lecture, I will discuss thermalization, ergodicity, and lack of them in classical systems. I will focus on paradigmatic example of spin glasses, and normal and anomalous diffusion processes. I will turn then to quantum closed systems, which, when perturbed or quenched, tend to “thermalize” in an ergodic way: the reduced density matrix of a block of the system is well approximated by the Gibbs-Boltzmann canonical ensemble, at least for averages of local observables and their-not-too-high-moments. There are several exceptions from this situation: i) Systems with multiple constants of motion are described by generalized Gibbs-Boltzmann ensembles; ii) Many-body localization (MBL) occurs in certain disordered systems; iii) MBL may occur also in non-disordered systems; iv) Local conservation laws, like the Gauss law, may prevent thermalization, for instance in Lattice Gauge Theory (LGT) models; v) Systems may exhibit quantum many-body scars, i.e. low entropy states that cause “weak” ergodicity breaking; vi) The latter occur frequently in confined LGT, but also in deconfined ones.

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