$D$-dimensional aether charged black hole and aether waves in M-subset of Einstein-aether theory

TL;DR

This paper investigates black hole solutions and gravitational wave polarizations in a specific subset of Einstein-aether theory, revealing unique properties of aether charge, exact Smarr and first law formulations, and mode speeds independent of spacetime dimensions.

Contribution

It introduces a new M-subset of Einstein-aether theory with exact black hole solutions, mode speed analysis, and polarization characteristics, expanding understanding of Lorentz-violating gravity models.

Findings

Existence of D-dimensional Reissner-Nordstrom black hole solutions with aether charge bounds.

Exact construction of Smarr formula and first law using Killing potential.

Spin-2 and spin-1 modes propagate at unit speed, with unique polarization features.

Abstract

We study the black hole solution and gravitational wave polarizations in a M-subset of the Einstein-aether theory with Lorentz invariance violated by an unit norm vector field -- the aether field $u^a$. This M-subset of Einstein-aether theory has a form of Einstein-Maxwell theory with a term of Lagrange multiplier potential $\lambda(u_au^a\mp1)$. When the aether field is timelike or spacelike, there exists a static solution -- $D$-dimensional Reissner-Nordstrom form of black hole solution, in which the aether charge have a minimum and maximum values. This conception of the aether charge doesn't exist in the $c_i$ subset of the Einstein-aether theory. The Smarr formula and the first law can be exactly constructed via the extended method of Killing potential. For the linearized M-subset Einstein-aether theory with the timelike aether field, we find the speed of spin-2 modes is unit, which aren't dependent on spacetime dimensions $D$ and aether constant $b_1$, but some parts of polarizations are disappeared. The speed of spin-1 modes is unit also. The third kind mode is the longitudinal aether-metric mode, which is linearly time dependent and not the spin-0 mode reported in the $c_i$ subset Einstein-aether theory.