Loss of coherence and coherence protection from a graviton bath

Toroš, M. , Mazumdar, A. and Bose, S. (2024) Loss of coherence and coherence protection from a graviton bath. Physical Review D, (Accepted for Publication)

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Abstract

We consider a quantum harmonic oscillator coupled with a graviton bath. We discuss the loss of coherence in the matter sector due to the matter-graviton vertex interaction, which leads to a loss of coherence provided that the matter-wave system is allowed to emit gravitons by the kinematics. Working in the quantum-field-theory framework, we obtain a master equation by tracing away the gravitational field at the leading order ∼ O ( G ) and ∼ O ( c − 2 ) . We find that the decoherence rate is proportional to the cube of the harmonic trapping frequency and vanishes for a free particle, as expected for a system without a mass quadrupole. Furthermore, our quantum model of graviton emission recovers the known classical formula for gravitational radiation from a classical harmonic oscillator for coherent states with a large occupation number. In addition, we find that the quantum harmonic oscillator eventually settles in a steady state with of the ground and first excited states. While classical emission of gravitational waves would make the harmonic system loose all of its energy, our quantum field theory model does not allow the number states | 1 ⟩ and | 0 ⟩ to decay via graviton emission. In particular, the superposition of number states 1 √ 2 [ | 0 ⟩ + | 1 ⟩ ] is a steady state and never decoheres.

Item Type:Articles
Additional Information:MT acknowledges funding by the Leverhulme Trust (RPG-2020-197). S.B. would like to acknowledge EPSRC grants (EP/N031105/1, EP/S000267/1, and EP/X009467/1) and grant ST/W006227/1.
Status:Accepted for Publication
Refereed:Yes
Glasgow Author(s) Enlighten ID:Toros, Dr Marko
Authors: Toroš, M., Mazumdar, A., and Bose, S.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review D
Publisher:American Physical Society
ISSN:2470-0010
ISSN (Online):2470-0029

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
308508Quantum Mechanics in a Rotating WorldMiles PadgettLeverhulme Trust (LEVERHUL)RPG-2020-197P&S - Physics & Astronomy