Anisotropic cubic curvature couplings

Bailey, Quentin G.

doi:10.1103/physrevd.94.065029

Cited by 33 publications

(57 citation statements)

References 96 publications

(138 reference statements)

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“…We consider both the pure-gravity sector [24] and the spin-independent gravitationally-coupled fermion sector [25] in the limit of linearized gravity. Though work extending the framework to include higher dimension operators [22,23,26] and nonlinear gravity [27] is now well underway, treatment of these operators lies beyond our present scope. Here we summarize aspects of the SME framework relevant for this work.…”

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confidence: 99%

Superconducting-Gravimeter Tests of Local Lorentz Invariance

2017

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Superconducting-gravimeter measurements are used to test the local Lorentz invariance of the gravitational interaction and of matter-gravity couplings. The best laboratory sensitivities to date are achieved via a maximum-reach analysis for 13 Lorentz-violating operators, with some improvements exceeding an order of magnitude.Local Lorentz invariance is among the foundational building blocks of General Relativity (GR). Though GR provides an impressive description of the wide variety of gravitational phenomena, standard lore holds that GR may be the low-energy limit of an underlying theory that merges gravitation and quantum physics, such as string theory. Local Lorentz violation may arise in such an underlying framework [1]. Hence tests of local Lorentz invariance probe the core construction of GR and may provide clues about the structure of new physics at the quantum-gravity scale. These ideas triggered the development of a comprehensive effective field theory based framework [2,3] for testing Lorentz symmetry used in many modern searches for violations [4].Superconducting gravimeters [5] have generated a vast amount of information about the gravitational field of the Earth. Devices functioning at over 2 dozen locations around the globe generate data at minute intervals for the Global Geodynamics Project (GGP) [6]. In some cases measurements span more than a decade, and sensitivities to local variations in the gravitational field approaching parts in 10 12 can be extracted for variations with periods on the order of a day. Stability at the level of parts in 10 9 per year [5] has also been achieved. Though the primary use of the data is in geophysical applications, the nature of the data clearly also depends on the foundational theories of physics. Hence these data sets provide opportunities to test fundamental physics [7,8]. The search for preferred frame effects in gravitational physics, a particular Lorentz-symmetry violating scenario, was perhaps the first application of superconducting gravimeters to tests of foundational theory [9].In the 4 decades since those early tests, interest in Lorentz violation has surged [10], as have theoretical and experimental developments [11][12][13]. In addition to the search for preferred frame effects as a signal of alternatives to GR [14], more general types of Lorentz violation are now actively sought as a possible signal of new physics at the Planck scale [4]. Though performing Planck-scale experiments directly will likely remain infeasible for the foreseeable future, experimental information about the nature of the underlying theory can be attained by searching for tiny Planck-suppressed effects in experiments at presently accessible energies. Lorentz violation provides a useful candidate Planck-suppressed effect [1], and the gravitational Standard-Model Extension (SME) provides a field-theory based framework for organizing a systematic search [2,3,15]. While sensitivities to SME coefficients for Lorentz violation have been achieved in a variety of gravitational systems...

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confidence: 99%

Superconducting-Gravimeter Tests of Local Lorentz Invariance

2017

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“…for any four-vector k b . Note that given the symmetries of P abcdef , R abcef , and Q bcef , the condition (9) is equivalent to (7) being invariant under the customary gauge transformation h ab → h ab + ∂ (a ξ b) . In principle, any set of tensors P abcdef , R abcef , and Q bcef with the appropriate symmetries and satisfying (9) would provide a Lorentz-violating equation of motion for h ab .…”

Section: Constructing the Propagatormentioning

confidence: 99%

“…For this reason, research into gravitational phenomenology in the context of the SME has almost entirely focused on the description of metric perturbations about flat spacetime [4,5,6], and almost entirely on the linearized equations of motion for these perturbations. (However, see [7] for a case where second-order perturbation theory can be applied in a Lorentz-violating gravitational context.) In some models involving a "Lorentz-violating" tensor field (i.e., a tensor field whose dynamics give it a non-zero vacuum expectation value), the perturbations of the Lorentz-violating tensor field effectively decouple from the linearized Einstein equation, and the linearized Einstein equation can therefore be put into a standard form involving the linearized Riemann tensor (and its derivatives) and various contractions of the background value of the Lorentz-violating tensor.…”

Section: Introductionmentioning

confidence: 99%

Lorentz-violating gravity and the bootstrap procedure

Seifert¹

2020

Class. Quantum Grav.

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In conventional gravitational physics, the so-called "bootstrap procedure" can be used to extrapolate from a linear model of a rank-2 tensor to a full non-linear theory of gravity (i.e., general relativity) via a coupling to the stress-energy of the model. In this work, I extend this procedure to a "Lorentz-violating" gravitational model, in which the linear tensor field and the matter fields "see" different metrics due to a coupling between the tensor field and a background vector field. The resulting model can be thought of as a generalized Proca theory with a non-minimal coupling to conventional matter. It has a similar linearized limit to the better-known "bumblebee model", but differs at higher orders in perturbation theory. Its effects are unobservable in FRW spacetimes, but are expected to be important in anisotropic cosmological spacetimes.

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“…While the field theory procedures to take resonance effects into account are available [75], they have not yet been implemented in the existing preliminary computations, which therefore suffer from an essentially uncontrolled source of systematic uncertainty. 10 In decays to pseudoscalar mesons, there are results for the vector, scalar, and tensor form factors for B s → K + − decays by HPQCD [76] and FNAL/MILC [77], the latter paper also providing results for B → π + − . Concerning channels with vector mesons in the final state, Horgan et al have obtained the seven form factors relevant for B → K * + − (as well as those for B s → φ + − ) in [78] using NRQCD b quarks and asqtad staggered light quarks.…”

Section: Rare Decaysmentioning

confidence: 99%