Circular motion analogue Unruh effect in a 2 + 1 thermal bath: robbing from the rich and giving to the poor

D Bunney, Cameron R.; Louko, Jorma

Abstract

The Unruh effect states that a uniformly linearly accelerated observer with proper acceleration a experiences the Minkowski vacuum as a thermal state at temperature 𝘛ᵤ = 𝑎/(2π). An observer in uniform circular motion experiences a similar effective temperature, operationally defined in terms of excitation and de-excitation rates, and physically interpretable in terms of synchrotron radiation, but this effective temperature depends not just on the acceleration but also on the orbital speed and the excitation energy. In this paper we consider an observer in uniform circular motion when the Minkowski vacuum is replaced by an ambient thermal bath, and we address the interplay of ambient temperature, Doppler effect, acceleration, and excitation energy. Specifically, we consider a massless scalar field in 2 + 1 spacetime dimensions, probed by an Unruh–DeWitt detector, in a Minkowski (rather than proper) time formulation: this setting describes proposed analogue spacetime systems in which the effect may become experimentally testable, and in which an ambient temperature will necessarily be present. We establish analytic results for the observer's effective temperature in several asymptotic regions of the parameter space and provide numerical results in the interpolating regions, finding that an acceleration effect can be identified even when the Doppler effect dominates the overall magnitude of the response. We also identify parameter regimes where the observer sees a temperature lower than the ambient temperature, experiencing a cooling Unruh effect.

Citation

D Bunney, C. R., & Louko, J. (2023). Circular motion analogue Unruh effect in a 2 + 1 thermal bath: robbing from the rich and giving to the poor. Classical and Quantum Gravity, 40(15), Article 155001. https://doi.org/10.1088/1361-6382/acde3b

• Journal Article Type: Article
• Acceptance Date: Jun 13, 2023
• Online Publication Date: Jun 28, 2023
• Publication Date: Aug 3, 2023
• Deposit Date: Jun 29, 2023
• Publicly Available Date: Jun 29, 2023
• Journal: Classical and Quantum Gravity
• Print ISSN: 0264-9381
• Electronic ISSN: 1361-6382
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 40
• Issue: 15
• Article Number: 155001
• DOI: https://doi.org/10.1088/1361-6382/acde3b
• Keywords: Unruh effect in thermal bath, acceleration radiation, Unruh effect, circular motion Unruh effect
• Public URL: https://nottingham-repository.worktribe.com/output/21917566
• Publisher URL: https://iopscience.iop.org/article/10.1088/1361-6382/acde3b