Regular Article

Polaronic effects in one-dimensional Fermi gas

¹ State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P.R. China
² School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
³ School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, P.R. China

^a e-mail: yadong.s@yahoo.com

Received: 22 November 2018
Received in final form: 16 January 2019
Published online: 21 May 2019

Abstract

Using the variational method and exact Bethe ansatz (BA) method, we studied the effects of an impurity immersed in a one-dimensional (1D) Fermi sea. With attractive interactions between them, the impurity is dressed up by surrounding particles in Fermi sea and forms a polaron. For equal masses and heavy polaron systems, we calculated the binding energy, effective mass, momentum distribution and Tan contact. In the strongly attractive limit, the impurity forms a dimer with inner fermion in Fermi sea which just accords with the highly imbalanced 1D Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state in experiment. We find that the heavy impurity is dressed more deeply with Fermi sea in whole interaction regime. Furthermore, we explore the complete influence of particle-hole excitation in Fermi polaron system in 1D. We find a shocking phenomenon that the hole term in Fermi sea has a great influence on the Tan relation even in the attractive interaction regime.