Gravitational phenomenology in higher-dimensional theories and strings

Kostelecký, V. Alan; Samuel, Stuart

doi:10.1103/physrevd.40.1886

Cited by 489 publications

(472 citation statements)

References 68 publications

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“…In the specific model investigated below, we concentrate on the simple Maxwelltype kinetic term (57). In doing so, we seem closer to Kostelecky and Samuel [42] Let us look back to our first ansatz for an aether Lagrangian in Eq.(4). There we had derivative terms of the nonmetricity.…”

Section: Curvaturementioning

confidence: 99%

“…There we had derivative terms of the nonmetricity. However, such terms are not allowed in first order MAG, see the gauge Lagrangian V in (42). Only an algebraic dependency of the field strengths Q αβ , T α , R α β , mostly quadratic for dimensional reasons, is allowed.…”

Section: Curvaturementioning

confidence: 99%

“…It is a first order LagrangeNoether gauge formalism of non-Abelian nature and our gauge field equations (53) and (54) are coupled nonlinear partial differential equations of second order in the gauge potentials g αβ , Γ α β . The only hand waving is involved in the explicit choice of the gauge Lagrangian V (g αβ , ϑ α , Q αβ , T α , R α β ) in (42). Since we want to develop a model that is an image of the J&M theory, we have to hand pick a suitable V .…”

Section: Curvaturementioning

confidence: 99%

“…In an attempt to violate Lorentz invariance locally, J&M [37] introduced an extra timelike 4-vector field u of unit length, see also [8,12,17,18,21,26,36,46] and the earlier work of Gasperini [23,24] and Kostelecky and Samuel [42]. This "aether field" is governed by a Lagrangian carrying a kinetic term ∼ (∇u) 2 and a massive term ∼ u 2 .…”

Section: Introductionmentioning

confidence: 99%

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Einstein-aether theory, violation of Lorentz invariance, and metric-affine gravity

2005

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We show that the Einstein-aether theory of Jacobson and Mattingly (J&M) can be understood in the framework of the metric-affine (gauge theory of) gravity (MAG).We achieve this by relating the aether vector field of J&M to certain post-Riemannian nonmetricity pieces contained in an independent linear connection of spacetime.Then, for the aether, a corresponding geometrical curvature-square Lagrangian with a massive piece can be formulated straightforwardly. We find an exact spherically symmetric solution of our model.

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Section: Curvaturementioning

confidence: 99%

Section: Curvaturementioning

confidence: 99%

Section: Curvaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Einstein-aether theory, violation of Lorentz invariance, and metric-affine gravity

2005

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“…For instance, the possibility of spontaneous Lorentz and CPT breaking in the framework of string field theory was discovered more than a decade ago [67][68][69][70][71][72][73][74]. Subsequent studies have considered other mechanisms for Lorentzviolating vacua including spacetime foam [75,76], nontrivial spacetime topology [77], loop quantum gravity [78,79], realistic noncommutative field theories [80][81][82][83], and spacetime-varying couplings [1,84].…”

Section: Coordinate Independencementioning

confidence: 99%

The Lorentz-Violating Extension of the Standard Model

Lehnert

2004

Beyond the Desert 2003

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Abstract. Quantum-gravity effects are expected to be suppressed by the Planck mass. For experimental progress it is therefore important to identify potential signatures from Planck-scale physics that are amenable to ultrahigh-precision tests. It is argued that minuscule violations of Lorentz and CPT symmetry are candidate signals. In addition, theoretical and experimental aspects of the Standard-Model Extension, which describes the emergent low-energy effects, are discussed. MotivationAn important open question in our understanding of nature at its fundamental level concerns a unified quantum description of all fundamental interactions including gravity. Such a theory is likely to become dominant only as the Planck scale is approached, so that quantum-gravity effects are expected to be minuscule at presently attainable energies. Moreover, the absence of a fully realistic and viable candidate underlying theory provides a major obstacle for the identification of concrete quantum-gravity signatures that can be searched for in present-day or near-future experiments.A possible approach to overcome this phenomenological issue is to determine exact relations in the currently accepted laws of physics that may be violated in prospective fundamental theories and that can be tested with ultrahighprecision. Symmetries typically satisfy these criteria. For example, Lorentz and CPT invariance are cornerstones of our present understanding of nature at the fundamental level, and a variety of Lorentz and CPT tests belong to the most sensitive null experiments available. Lorentz and CPT violation is also a key feature of certain approaches to underlying physics.For example, couplings varying on cosmological scales are one possible source of Lorentz and CPT violation [1]. This fact does not come as a surprise: parameters dependent on spacetime break translational invariance, and translations, rotations, and boosts are linked in the Poincaré group. Thus, violations of translation symmetry can also affect Lorentz invariance. This can be understood intuitively as follows. The equations of motion typically contain the gradient of the coupling, which selects a preferred direction in spacetime leading to apparent Lorentz violation.In this talk, we discuss some theoretical and experimental aspects of the Standard-Model Extension (SME) [2][3][4][5][6][7], which is the low-energy framework for Lorentz-breaking effects. The SME is a dynamical model constructed to contain all Lorentz-and CPT-violating lagrangian terms consistent with coordinate

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Testing a CPT- and Lorentz-Violating Extension of the Standard Model

Kostelecký

Physics of Mass

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The formulation and some experimental implications of a general Lorentz-violating extension of the standard model are reviewed. The theory incorporates both CPTpreserving and CPT-breaking terms. It is otherwise a conventional quantum field theory, obtained under the assumption that Lorentz symmetry is spontaneously broken in an underlying model. The theory contains the usual standard-model gauge structure, and it is power-counting renormalizable. Energy and momentum are conserved. Despite the violation of Lorentz symmetry, the theory exhibits covariance under Lorentz transformations of the observer inertial frame. A general Lorentz-violating extension of quantum electrodynamics can be extracted. The standard-model extension implies potentially observable effects in a wide variety of experiments, including among others measurements on neutral-meson oscillations, comparative studies in Penning traps, spectroscopy of hydrogen and antihydrogen, bounds on cosmological birefringence, measurements of muon properties, clock-comparison tests, and observations of the baryon asymmetry.1 Invited talk at the conference Beyond the Standard Model,

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Gravitational phenomenology in higher-dimensional theories and strings

Cited by 489 publications

References 68 publications

Einstein-aether theory, violation of Lorentz invariance, and metric-affine gravity

Einstein-aether theory, violation of Lorentz invariance, and metric-affine gravity

The Lorentz-Violating Extension of the Standard Model

Testing a CPT- and Lorentz-Violating Extension of the Standard Model

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