Search arXiv⌕ Search

arXiv · gr-qc/0410001

Einstein-Aether Theory

Abstract

We review the status of "Einstein-Aether theory", a generally covariant theory of gravity coupled to a dynamical, unit timelike vector field that breaks local Lorentz symmetry. Aspects of waves, stars, black holes, and cosmology are discussed, together with theoretical and observational constraints. Open questions are stressed.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C. Eling, T. Jacobson, D. Mattingly. 2005-01-16. Einstein-Aether Theory. https://arxiv.org/abs/gr-qc/0410001

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

An upper bound on the minimum orbital period of black holes

Previous research has focused on establishing lower bounds on the minimum orbital period of black holes. In this work, we explore the complementary question of whether an upper bound exists for the minimum orbital period of black holes. We investigate the minimum orbital periods of three types of black holes: Schwarzschild, Reissner-Nordström and Kerr-Newman black holes. We find that the minimum orbital period of these black holes is bounded by an upper limit $T_{min} \leqslant 6\sqrt{3}πM$, where $M$ is the black hole mass. Our results suggest that this upper bound on the minimum orbital period may be a general property in black hole spacetimes.

gr-qc↗

Cosmological Variation of Proton-to-Electron Mass Ratio in a Chameleon-Brans-Dicke Theory

We investigate the cosmological variation of the proton-to-electron mass ratio, $μ=m_p/m_e$, within a generalized Brans-Dicke framework with two scalar fields : a geometric scalar field governing the effective gravitational coupling and a matter field whose effective potential has a Higgs-like symmetry-breaking structure. We consider a cosmological background described by a Padé-deformed $Λ$CDM and constrain it using a combination of late-time cosmological observational data-sets. We use the resulting expansion history to reconstruct the scalar-field and the matter-sector vacuum expectation value. We calculate the induced variation of $μ$ and compare it with observational constraints from quasar absorption spectra. We find that a standard Brans-Dicke model with a minimally coupled Higgs-like field produces an unphysical variation of $μ$. Only after introducing a chameleon-like coupling between the Brans-Dicke scalar and the baryonic matter, we find that the resulting variation is well-suppressed and satisfies the observational bounds.

gr-qc↗

Observer-robust energy condition verification for warp drive spacetimes

Energy-condition tests for warp-drive spacetimes must account for all admissible causal directions at each point. We use the classical S-lemma to express the null, weak, and strong conditions as $4\times4$ linear matrix inequalities; the dominant condition requires two such tests. These criteria require neither Hawking-Ellis classification nor a rapidity cutoff. For the null condition in a fixed orthonormal tetrad, the optimized multiplier margin equals half the minimum normalized null-energy contraction. Interval evaluation of the metric and curvature provides pointwise certificates and global bounds on its minimum over the bubble wall. On flat unit-lapse slices, the momentum constraint relates Eulerian momentum to shift vorticity. For smooth shifts on all of Euclidean space with bounded vorticity, momentum vanishes identically precisely for a gradient plus rigid rotation. For shifts linear in speed, integrated negative Eulerian energy scales exactly quadratically when finite, with a fixed profile and integration domain on these slices. We implement the tests in Warpax, a JAX toolkit, and compare four warp-drive geometries at matched parameters across subluminal and superluminal speeds. At the reference parameters, the global bounds establish null-energy violation in all four bubble walls. The ideal irrotational Rodal profile has zero Eulerian momentum and is everywhere Type I; Type-IV regions are detected in the other sampled walls. For Rodal, the Eulerian reading misses about $73\%$ of the sampled wall weak-energy violations. These numerical type labels and sampled fractions are distinct from the interval bounds. Finite-segment null-geodesic integrals and flat-space quantum-inequality estimates supplement the pointwise analysis.

gr-qc↗