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Nondestructive Optomechanical Detection Scheme for Bose-Einstein Condensates

Cisco Gooding1, Cameron R. D. Bunney2, Samin Tajik3, Sebastian Erne4, Steffen Biermann5, Jörg Schmiedmayer4, Jorma Louko5, William G. Unruh3,6, and Silke Weinfurtner5,7

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Phys. Rev. Lett. 136, 043401 – Published 26 January, 2026

DOI: https://doi.org/10.1103/4yfh-tm4f

Abstract

We present a two-tone heterodyne optical readout scheme to extract unequal-time density correlations along an arbitrary stationary interaction path from a pancake-shaped Bose-Einstein condensate, using a modulated laser probe. Analyzing the measurement noise both from imprecision and backaction, we identify the standard quantum limit for the signal-extraction scheme, and examine how a class of two-mode squeezed initial states can be used to push beyond this limit. As an application, we show how the readout scheme can be used for an experimentally feasible realization of acceleration dependence of quantum-vacuum fluctuations in the system, including the analog spacetime circular motion Unruh effect. The scheme is adaptable beyond Bose-Einstein condensates, providing nondestructive access to unequal-time correlations in quantum fluids.

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Phys. Rev. Lett. 136, 043401– Published 26 January, 2026
  • Received 2 August 2025
  • Revised 4 December 2025
  • Accepted 19 December 2025
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