Quantum States and Phases in Driven Open Quantum Systems with Cold Atoms

TL;DR

This paper explores how driven open quantum systems, specifically cold atom setups, can be engineered to reach specific quantum states and phases through reservoir engineering, revealing new non-equilibrium quantum phenomena.

Contribution

It provides a detailed analysis of driven dissipative Bose-Einstein condensates and fermionic pairs, demonstrating how system-reservoir coupling can produce long-range order and complex quantum phases.

Findings

Pure long-range order in non-interacting lattice gases

Weak interactions cause condensate depletion in 3D

Emergence of Luttinger liquid or Kosterlitz-Thouless phases in 1D/2D

Abstract

An open quantum system, whose time evolution is governed by a master equation, can be driven into a given pure quantum state by an appropriate design of the system-reservoir coupling. This points out a route towards preparing many body states and non-equilibrium quantum phases by quantum reservoir engineering. Here we discuss in detail the example of a \emph{driven dissipative Bose Einstein Condensate} of bosons and of paired fermions, where atoms in an optical lattice are coupled to a bath of Bogoliubov excitations via the atomic current representing \emph{local dissipation}. In the absence of interactions the lattice gas is driven into a pure state with long range order. Weak interactions lead to a weakly mixed state, which in 3D can be understood as a depletion of the condensate, and in 1D and 2D exhibits properties reminiscent of a Luttinger liquid or a Kosterlitz-Thouless critical phase at finite temperature, with the role of the ``finite temperature'' played by the interactions.