Vacuum entanglement probes for ultra-cold atom systems

Abstract

This study explores the transfer of nonclassical correlations from an ultra-cold atom system to a pair of pulsed laser beams. Through nondestructive local probe measurements, we introduce an alternative to destructive techniques for mapping BEC entanglement. Operating at ultralow temperatures, the setup emulates a relativistic vacuum field. We show that lasers can serve as Unruh-DeWitt detectors for BEC vacuum phonons. A quantum vacuum holds intrinsic entanglement, transferable to distant probes briefly interacting with it - a phenomenon termed `entanglement harvesting'. Our study accomplishes two primary objectives: first, establishing a mathematical equivalence between a pair of pulsed laser probes interacting with an effective relativistic field and the entanglement harvesting protocol; and second, to closely examine the potential and persisting obstacles for realising this protocol in an ultra-cold atom experiment.

v2: 18 pages and 3 figures, including Appendices (published version) v1: 12 pages and 3 figures, including the Supplemental Material / Appendices