Dissipation in finite Fermi systems

Eliade N. Stefanescu

Jun’ichi Ozaki, Masaki Tezuka, Norio Kawakami

A. Olmi

Sergiy Radionov

We address the problem of the dissipative character of collective motion in finite Fermi systems. We study this problem from the point of view of chaotic features of the fermionic degrees of freedom of the many-body Fermi systems. Our main aim is of two kinds: first, we investigate how quantum chaos sets in in many-body systems and then, we try to relate quantum many-body chaos of the intrinsic fermionic degrees of freedom to the corresponding dissipative properties of the macroscopic collective motion. The main focus is on the role of two-body interaction between fermions in onset of the quantum many-body chaos and collective dissipation.

C. Toepffer, P.‐G. Reinhard

J. Zhou, Wei Zhang

We study the polaron problem of an impurity immersed in a dissipative spin-orbit coupled Fermi gas via a non-self-consistent T -matrix method. We first propose an experimental scheme to realize a spin-orbit coupled Fermi bath with dissipation, and show that such a system can be described by a non-Hermitian Hamiltonian that contains an imaginary spin-flip term and an imaginary constant shift term. We find that the non-Hermiticity will change the single-particle dispersion of the bath gas, and modify the properties of attractive and repulsive polarons such as energy, quasi-particle residue, effective mass, and decay rate. We also investigate the Thouless criteria corresponding to the instability of the polaron-molecule transition, which suggests a molecule state is more facilitated with stronger bath dissipation. Finally, we consider the case with finite impurity density and calculate the interaction between polarons. Our result extends the study of polaron physics to non-Hermitian systems and may be realized in future experiments.