Quantum Nucleation and Macroscopic Quantum Tunneling in Cold-Atom Boson-Fermion Mixtures

TL;DR

This paper investigates quantum nucleation and macroscopic quantum tunneling in cold-atom boson-fermion mixtures, deriving effective actions and analyzing the influence of dissipation near phase transitions.

Contribution

It provides a microscopic derivation of nucleation rates and analyzes the crossover to quantum tunneling in cold-atom mixtures, highlighting the role of dissipation.

Findings

Quantum nucleation rates depend on density and fermion-boson mass ratio.

Crossover to macroscopic quantum tunneling is characterized and analyzed.

Dissipation from fermionic excitations significantly affects transition dynamics.

Abstract

Kinetics of phase separation transition in boson-fermion cold atom mixtures is investigated. We identify the parameters at which the transition is governed by quantum nucleation mechanism, responsible for the formation of critical nuclei of a stable phase. We demonstrate that for low fermion-boson mass ratio the density dependence of quantum nucleation transition rate is experimentally observable. The crossover to macroscopic quantum tunneling regime is analyzed. Based on a microscopic description of interacting cold atom boson-fermion mixtures we derive an effective action for the critical droplet and obtain an asymptotic expression for the nucleation rate in the vicinity of the phase transition and near the spinodal instability of the mixed phase. We show that dissipation due to excitations in fermion subsystem play a dominant role close to the transition point.