Maciej Lewenstein graduated as MSc at Warsaw University in 1978 and PhD at Universität Essen in 1983. He was research fellow in Essen, at Harvard, Commisariat a l'Énergie Atomique in Saclay and at Joint Institute for Laboratory Astrophysics at Boulder. He was on faculty of Centre for Theoretical Physics 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 published over 600 papers, cited in WoS over 42000 times with H-index=101. Recipient of 3 ERC AdGs. 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. This will be an online event. Please register at the following Zoom link: https://zoom.us/webinar/register/WN_WifhpYYDR5i67rQsWkVsAw After registration, you will receive a confirmation email. The Colloquium will also be livestreamed from the ICTP website. All are most welcome to attend.