The seminar will take place from 11-12 p.m. PDT in Physics 375 North. Our speaker is Francisco Machado (UC Berkeley). Details are below.
Out-of-equilibrium dynamics and phases of matter in AMO systems
The past few decades have witnessed an explosive development of atomic, molecular and optical (AMO) platforms. Previously restricted to a single qubit, quantum coherent manipulation is now available across large arrays of quantum particles. This unprecedented control over many-body quantum matter has enabled the direct study of isolated quantum dynamics away from equilibrium, and has opened an entirely new landscape for exploring different physical phenomena in AMO systems, motivating a new set of theoretical inquiries and explorations. In this talk, I explore some of this landscape by focusing on two different classes of dynamics: prethermalization, and hydrodynamics.
In the first part of my talk I will introduce the phenomenology of prethermalization in periodically driven (Floquet) systems and how it can be modified by the presence of long-range interactions, ubiquitous in AMO platforms. I will discuss how one can prove the existence of an exponentially long-lived prethermal regime (controlled by the frequency of the drive) that hosts an effective static description with a novel and emergent symmetry protected by the time translation symmetry of the drive. Using these insights, I will present a numerical study and a subsequent experimental observation of a prethermal discrete time crystal, an intrinsically out-of-equilibrium prethermal phase of matter that breaks the discrete time translation symmetry of the system.
In the second part, I will turn to the study of transport in isolated quantum integrable systems; I will start by discussing how the presence of an extensive number of quasi-local conserved quantities can modify the underlying transport in important ways. I will then focus on models exhibiting non-Abelian symmetries (and beyond), demonstrating that their transport is neither ballistic nor diffusive, but rather superdiffusive, and that it is characterized by the Kardar-Parisi-Zhang universality class. Finally, I will briefly discuss an experiment where this phenomenon was explored using atoms trapped in an optical lattice, and where the non-linear nature of this transport was observed.