2:00–3:00 pm
Please Join us:
Kai-Xuan Yao’s PhD Thesis Defense
Thursday, December 1, 2022 at 2:00 pm CST
DOMAIN WALL DYNAMICS AND MANY-BODY ECHO IN DRIVEN BOSE EINSTEIN CONDENSATES
Ultracold atoms provide a versatile platform for quantum simulation, offering a great deal of control on system parameters such as potential landscape and interparticle interaction. One popular method to leverage this flexibility to study novel physics is Floquet engineering, where one periodically drives the system to realize phenomena inaccessible to static systems. On the other hand, Bose-Einstein condensates provide a scalable and clean venue to study many-body physics, where tens of thousands of atoms share the same quantum state while interacting with each other.
With driven Bose-Einstein condensates, we study two novel many-body phenomena. First, we create domain walls in the condensate, which are stable topological defects that behave as emergent particle-like excitations. The domain walls are found to display emergent dynamical properties drastically different from the constituent atoms. Second, we study the time reversal of a many-body system coupled to a continuum. The dynamics of such systems typically exhibit rapidly growing subsystem entropy, which according to classical thermodynamics appears irreversible. We are able to achieve significant reversal of the complex many-body dynamics by devising a technique inspired by the famous ‘spin echo’, which we call the ‘many-body echo’. Our work addresses two major standing questions in quantum many-body physics: emergence and thermalization, and opens up opportunities to realize even more exotic phenomena in the lab.
Committee Members:
Cheng Chin (Chair)
Andrew Cleland
Hannes Bernien
Michael Levin
Kai-Xuan will be a Quantitative Researcher at Citadel.