Speaker:Prof. Jhih-Shih You, Department of Physics, National Taiwan Normal University

Place: NTHU Physics Department,  Room 124

Time: 10/26, 13:30

Title: Atomtronics with a spin: Full counting statistics, Ramsey interferometry and nonequilibrium orthogonality catastrophe in cold quantum gases
 
Abstract: In this talk, I will first discuss the real-time Ramsey response of heavy quantum impurities immersed in a Fermi gas at zero and at finite temperature. Then I will introduce an ultracold atom setup, analogous to a spintronics device, which generates spin transport induced by an impurity atom immersed in a spin-imbalanced two-component Fermi gas. By manipulating the internal spin degrees of freedom of the Fermi system, one can directly investigate the full counting statistics of spin flips. Moreover, since the impurity interacts with a many-body environment that is out of equilibrium, our setup provides a way to realize the non-equilibrium orthogonality catastrophe.  For the impurity response at late time, we are able to derive analytical expressions, which reveal an intimate connection of the decay rate of the Ramsey contrast and the full counting statistics of spin flips. Our study paves a way for controlling and harnessing fermionic many-body states in atomtronics.