https://doi.org/10.1140/epjc/s10052-025-14099-9
Regular Article - Theoretical Physics
Rescuing the Unruh effect in Lorentz violating gravity
1
SISSA, Via Bonomea 265, 34136, Trieste, Italy
2
INFN Sezione di Trieste, Via Valerio 2, 34127, Trieste, Italy
3
IFPU-Institute for Fundamental Physics of the Universe, Via Beirut 2, 34014, Trieste, Italy
4
Institut de Fisica d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193, Bellaterra, Barcelona, Spain
Received:
31
October
2024
Accepted:
19
March
2025
Published online:
4
April
2025
While the robustness of Hawking radiation in the presence of UV Lorentz breaking is well-established, the Unruh effect has posed a challenge, with a large literature concluding that even the low-energy restoration of Lorentz invariance may not be sufficient to sustain this phenomenon. Notably, these previous studies have primarily focused on Lorentz-breaking matter on a conventional Rindler wedge. In this work, we demonstrate that considering the complete structure of Lorentz-breaking gravity, specifically the presence of a hypersurface orthogonal æther field, leads to the selection of a new Rindler wedge configuration characterized by a uniformly accelerated æther flow. This uniform acceleration provides a reference scale for comparison with the Lorentz-breaking one, thus ensuring the persistence of the Unruh effect in this context. We establish this by calculating the expected temperature using a Bogolubov approach, and by analyzing the response of a uniformly accelerated detector. We suggest that this resilience of the Unruh effect opens interesting possibilities towards future developments for using it as a tool to constrain Lorentz breaking theories of gravity.
© The Author(s) 2025
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