ICTP Colloquium 23 February

ICTP is pleased to be hosting a colloquium by Maciej Lewenstein, a theoretical physicist and a research professor at the Institute of Photonic Sciences, Spain.

His talk, titled "To Thermalize or not to Thermalize, that is the Question", will be livestreamed via Zoom on 23 February at 16:00 CET. Advance registration is required at:

https://zoom.us/webinar/register/WN_WifhpYvYDR5i67rQsWkVsAw

Maciej Lewenstein earned an MSc at Warsaw University in 1978 and a PhD at Universität Essen in 1983. He was a research fellow in Essen, at Harvard, Commisariat a l'Énergie Atomique in Saclay and at the Joint Institute for Laboratory Astrophysics at Boulder. He was on the faculty of the Centre for Theoretical Physic in Warsaw (1986-1994), CEA in Saclay (1995-1998), of the Leibniz University Hannover (1998-2005). In 2005, he moved to Catalonia as ICREA Research Professor at ICFO in Castelldefels. His interests include quantum optics, quantum physics, quantum information, atto-second science, and statistical physics. He is an acclaimed jazz writer and critic, author of “Polish Jazz Recordings and Beyond”. He has published over 600 papers, and is cited in WoS over 42000 times with an H-index=101.

Colloquium abstract: Quantum closed systems, when perturbed or quenched, tend to “thermalize” in an ergodic way: the reduced density matrix of a block of the system in 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 deconfined ones.