Superradiance in stars: non-equilibrium approach to damping of fields in stellar media

Chadha-Day, F.; Garbrecht, B.; McDonald, J.I.

Abstract

Superradiance in black holes is well-understood but a general treatment for superradiance in stars has until now been lacking. This is surprising given the ease with which we can observe isolated neutron stars and the array of signatures which would result from stellar superradiance. In this work, we present the first systematic pipeline for computing superradiance rates in rotating stars. Our method can be used with any Lagrangian describing the interaction between the superradiant field and the constituents of the star. Our scheme falls into two parts: firstly we show how field theory at finite density can be used to express the absorption of long wavelength modes into the star in terms of microphsyical scattering processes. This allows us to derive a damped equation of motion for the bosonic field. We then feed this into an effective theory for long wavelengths (the so-called worldline formalism) to describe the amplification of superradiant modes of arbitrary multipole moment for a rapidly rotating star. Our method places stellar superradiance on a firm theoretical footing and allows the calculation of the superradiance rate arising from any interaction between a bosonic field and stellar matter.

Citation

Chadha-Day, F., Garbrecht, B., & McDonald, J. (2022). Superradiance in stars: non-equilibrium approach to damping of fields in stellar media. Journal of Cosmology and Astroparticle Physics, 2022(12), https://doi.org/10.1088/1475-7516/2022/12/008

• Journal Article Type: Article
• Acceptance Date: Nov 14, 2022
• Online Publication Date: Dec 5, 2022
• Publication Date: 2022
• Deposit Date: Dec 6, 2022
• Publicly Available Date: Dec 6, 2022
• Journal: Journal of Cosmology and Astroparticle Physics
• Electronic ISSN: 1475-7516
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 2022
• Issue: 12
• DOI: https://doi.org/10.1088/1475-7516/2022/12/008
• Public URL: https://durham-repository.worktribe.com/output/1185086