Modeling Particle Loss in Open Systems using Keldysh Path Integral and Second Order Cumulant Expansion

Abstract

For open quantum systems, integration of the bath degrees of freedom using the second order cumulant expansion in the Keldysh path integral provides an alternative derivation of the effective action for systems coupled to general baths. The baths can be interacting and not necessarily Markovian. Using this method in the Markovian limit, we compute the particle loss dynamics in various models of ultra-cold atomic gases including a one-dimensional Bose-Hubbard model with two-particle losses and a multi-component Fermi gas with interactions tuned by an optical Feshbach resonance. We explicitly demonstrate that the limit of strong two-body losses can be treated by formulating an indirect loss scheme to describe the bath-system coupling. The particle-loss dynamics thus obtained is valid at all temperatures. For the one-dimensional Bose-Hubbard model, we compare it to solutions of the phenomenological rate equations. The latter are shown to be accurate at high temperatures.

14 pages, 4 figures

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Cited by in corpus (10)

• Many-Body Open Quantum Systems
• Large-scale universality in quantum reaction-diffusion from Keldysh field theory
• Effects of atom losses on a one-dimensional lattice gas of hardcore bosons
• Loss induced collective mode in one-dimensional Bose gases
• Universality and two-body losses: lessons from the effective non-Hermitian dynamics of two particles
• Correlation versus dissipation in a non-Hermitian Anderson impurity model
• Path Integral Approach to Input-Output Theory
• Reaction-diffusion dynamics of the weakly dissipative Fermi gas
• Kinetics of Quantum Reaction-Diffusion systems
• Space-time first-order correlations of an open Bose-Hubbard model with incoherent pump and loss