Distinguishing mesoscopic quantum superpositions from statistical mixtures in periodically shaken double wells

TL;DR

This paper proposes an echo technique using controlled periodic shaking to distinguish quantum superpositions from statistical mixtures in Bose-Einstein condensates in double wells, addressing experimental challenges in identifying true quantum coherence.

Contribution

It introduces a method for effective time-reversal via periodic shaking to differentiate superpositions from mixtures in many-particle quantum dynamics.

Findings

Numerical simulations confirm the scheme's effectiveness.

The method can distinguish superpositions from mixtures in Bose-Einstein condensates.

The approach offers a new way to analyze quantum coherence in experiments.

Abstract

For Bose-Einstein condensates in double wells, N-particle Rabi-like oscillations often seem to be damped. Far from being a decoherence effect, the apparent damping can indicate the emergence of quantum superpositions in the many-particle quantum dynamics. However, in an experiment it would be difficult to distinguish the apparent damping from decoherence effects. The present paper suggests using controlled periodic shaking to quasi-instantaneously switch the sign of an effective Hamiltonian, thus implementing an `echo' technique which distinguishes quantum superpositions from statistical mixtures. The scheme for the effective time-reversal is tested by numerically solving the time-dependent N-particle Schrodinger equation.