Boundary Time-Crystals
Dr. Fernando Lemini (ICTP (Intl. Center for Theoretical Physics), Trieste, Italy)

I discuss the concept of boundary time crystals, where the continuous time-translation symmetry breaking occurs only in a macroscopic fraction of a many-body quantum system. After introducing its definition and properties, we discuss in detail a solvable model where an accurate scaling analysis can be performed. The existence of the boundary time crystals is intimately connected to the emergence of a time-periodic steady state in the thermodynamic limit of a many-body open quantum system. I will also discuss the spreading of genuine multipartite correlations (GMC's) on such phases, showing results both for the (i) the structure (orders) of GMC's among its subsystem constituents, as well as (ii) their build-up dynamics for an initially uncorrelated state.