Quantum states and phases in driven open quantum systems with cold atoms

Abstract

An open quantum system, the time evolution of which is governed by a master equation, can be driven into a given pure quantum state by an appropriate design of the coupling between the system and the reservoir. This provides a route towards preparing many-body states and non-equilibrium quantum phases by quantum-reservoir engineering. Here, we discuss the example of a 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 and the atomic current represents 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 three dimensions can be understood as a depletion of the condensate, and in one and two dimensions exhibits properties reminiscent of a Luttinger liquid or a Kosterlitz–Thouless critical phase at finite temperature, with the role of the ‘finite temperature’ taken by the interactions. The coupling of a quantum system to its environment is usually associated with the unwanted effect of decoherence. But theoretical work shows that with suitably engineered couplings, dissipation can drive a system of cold atoms into desired many-body states and quantum phases.

Cite this article

Diehl, S., Micheli, A., Kantian, A. et al. Quantum states and phases in driven open quantum systems with cold atoms. Nature Phys 4, 878–883 (2008). https://doi.org/10.1038/nphys1073

View full text

>> Full Text:   Quantum states and phases in driven open quantum systems with cold atoms