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Amplification and generation bounds of gravity-induced entanglement in pulsed optomechanical systems

Daisuke Miki*, Alfred Li†, and Yanbei Chen‡

  • *Contact author: dmiki@caltech.edu
  • †Contact author: ali2@caltech.edu
  • ‡Contact author: yanbei@caltech.edu
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Phys. Rev. D 114, 064041 – Published 9 September, 2026

DOI: https://doi.org/10.1103/wv19-5t6p

Abstract

We investigate gravity-induced entanglement between the output optical fields of two red-detuned pulsed optomechanical systems with their masses coupled by mutual gravitational interaction. For each individual system, the optomechanical interaction realizes a beam-splitter state swap between an incident optical pulse and its mechanical mode. Using two rectangular pulses for each system—the first to imprint a nonclassical state on the mechanical modes and the second to read the gravitationally generated entanglement back onto the outgoing light—we show that the amount of entanglement can be amplified by preparing the input in a squeezed or Fock state. However, the threshold for entanglement generation is set by the competition between the gravitational coupling and thermal decoherence, gG>2γmNth, and cannot be lowered by any choice of input state. We prove this bound for two-mode Gaussian inputs and show that it continues to hold for Fock-state inputs. We further analyze how imperfect detection modifies the threshold and identify the entanglement-annihilating and entanglement-breaking regimes, which are set by the thermal decoherence accumulated over the interaction time, independent of the gravitational coupling.

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Phys. Rev. D 114, 064041– Published 9 September, 2026
  • Received 8 June 2026
  • Accepted 21 August 2026
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