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YMSC-BIMSA Quantum Information Seminar
Tackling Fermi polaron problem with a new variational approach
Tackling Fermi polaron problem with a new variational approach
Organizers
Speaker
Yueran Shi
Time
Wednesday, August 6, 2025 10:00 AM - 12:00 PM
Venue
Shuangqing-B627
Online
Zoom 230 432 7880
(BIMSA)
Abstract
The polaron problem describes an impurity interacting with a background medium, representing the highly imbalanced limit of a two-component system. Polarons are classified as Bose or Fermi by the majority statistics, with the Fermi case allowing impurity-fermion binding and interaction-driven transitions. Ultracold atomic gases provide an ideal platform, and various theoretical approaches have been developed to explore their properties.
We study low-dimensional Fermi polarons using a non-Gaussian variational approach. By employing the Lee-Low-Pines transformation, we decouple the impurity and then determine the ground state at fixed momentum via imaginary-time evolution. For conventional Fermi polarons, our results agree with previous studies and reveal a smooth crossover from polaron to molecular states. Extending to interacting backgrounds, we find that stronger interactions drive a continuous evolution from Fermi to Bose polarons.
We study low-dimensional Fermi polarons using a non-Gaussian variational approach. By employing the Lee-Low-Pines transformation, we decouple the impurity and then determine the ground state at fixed momentum via imaginary-time evolution. For conventional Fermi polarons, our results agree with previous studies and reveal a smooth crossover from polaron to molecular states. Extending to interacting backgrounds, we find that stronger interactions drive a continuous evolution from Fermi to Bose polarons.