[Joint CQSE & NCTS Seminar] Quantum impurities coupled to a Fermi gas: From Statistics of transport to atomtronics

Title: [Joint CQSE & NCTS Seminar] Quantum impurities coupled to a Fermi gas: From Statistics of transport to atomtronics
Speaker: Prof. Jhih-Shih You (National Taiwan Normal University)
Time: Apr. 21, 2023, 14:30-15:30
Place: NCTS Physics Lecture Hall, 4F, Chee-Chun Leung Cosmology Hall, NTU
Online: https://nationaltaiwanuniversity-zbh.my.webex.com/nationaltaiwanuniversity-zbh.my/j.php?MTID=m210715f40b11b5794be46cfbb95824d1

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.

Theoretical study on condensed matter and ultra-cold physics, with particular focus
on quantum geometry, topological matter, non-equilibrium phenomena, nonHermitian
physics and quantum phase transitions.

-Assistant Professor, Aug. 2020- Present
Department of Physics, National Taiwan Normal University, Taiwan
-Postdoctoral Scholar, Oct. 2017–Jul. 2020
Institute for Theoretical Solid State Physics, Leibniz Institute for Solid State and Materials Research in Dresden (IFW Dresden), Germany
-Postdoctoral Fellow, Sep. 2015–Sept. 2017
Department of Physics, Harvard University, USA
-Visiting Student, Sep. 2013 –Aug. 2015
Department of Physics, University of California, San Diego, USA

BS & MS & PhD, Department of Physics, National Tsing Hua University, Taiwan, 2015.

Referee for PRX, PRL, PRA, PRB, PR Materials, SciPost Physics, 2D Materials ,
Nano Letter, Nature.