Engineering tunable decoherence-free subspaces with collective atom-cavity interactions

TL;DR

This paper introduces methods to engineer and control a tunable, multi-dimensional decoherence-free subspace in atom-cavity systems, enabling high-fidelity state preparation for quantum information tasks.

Contribution

It presents schemes using external lasers to dynamically control a degenerate DFS in dissipative atom-cavity systems, including adiabatic shortcuts for improved state purity and fidelity.

Findings

DFS can be made multi-dimensional for quantum sensing and computation

External driving lasers enable transfer to highly entangled states within DFS

Adiabatic shortcuts improve state purity and fidelity during evolution

Abstract

We propose schemes to design and control a time-dependent decoherence-free subspace (DFS) in a dissipative atom-cavity system. These schemes use atoms with three internal energy levels, which allows for the DFS to be multi-dimensional--a condition important for quantum sensing, simulation, and computation. We consider the use of tunable external driving lasers to transfer the system from a coherent spin state to a highly degenerate DFS. We find that the typical state in the DFS is highly entangled. Throughout evolution the state is kept in an instantaneous DFS, thereby allowing for pure states to be prepared. We develop adiabatic shortcuts to carry out this evolution with higher purity and fidelity than standard adiabatic and dissipative methods.