Dynamic Stimulation of Quantum Coherence in Lattice Bosons

TL;DR

This paper demonstrates that non-equilibrium periodic driving can restore quantum coherence in lattice bosons, effectively reversing thermal decoherence and mimicking zero-temperature phase behavior in the Bose-Hubbard model.

Contribution

It introduces a method to use non-equilibrium driving to enhance quantum coherence, challenging the traditional view that thermal fluctuations always destroy long-range order.

Findings

Non-equilibrium driving can restore phase coherence in lattice bosons.

The phase boundary at finite temperature can resemble the zero-temperature phase diagram.

Potential experimental realization in cold atom systems.

Abstract

Thermal fluctuations tend to destroy long-range phase correlations. Consequently, bosons in a lattice will undergo a transition from a phase-coherent superfluid as the temperature rises. Contrary to common intuition, however, we show that non-equilibrium driving can be used to reverse this thermal decoherence. This is possible because the energy distribution at equilibrium is rarely optimal for the manifestation of a given quantum property. We demonstrate this in the Bose-Hubbard model by calculating the non-equilibrium spatial correlation function with periodic driving. We show that the non-equilibrium phase boundary between coherent and incoherent states at finite bath temperatures can be made qualitatively identical to the familiar zero-temperature phase diagram, and we discuss the experimental manifestation of this phenomenon in cold atoms.