Null Energy Condition violations in bimetric gravity

Baccetti, Valentina; Martín–Moruno, Prado; Visser, Matt

doi:10.1007/jhep08(2012)148

Cited by 55 publications

(54 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another interesting general feature of the bimetric solutions was noticed in [180]. There it was found that the effective stress-energy tensors that the bimetric interactions generate, i.e.the negative of V g mn and V f mn , never satisfy the null-energy condition simultaneously unless the two metrics are proportional.…”

Section: General Propertiesmentioning

confidence: 91%

“…There it was found that the effective stress-energy tensors that the bimetric interactions generate, i.e.the negative of V g mn and V f mn , never satisfy the null-energy condition simultaneously unless the two metrics are proportional. In more detail [180], found that if k m is a null-vector with respect to g , . Furthermore the inequalities only saturate for proportional solutions, when the interactions reduce to pure cosmological constant contributions (see section 5.3.1).…”

Section: General Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

Recent developments in bimetric theory

Schmidt-May

Strauss

2016

J. Phys. A: Math. Theor.

198

240

View full text Add to dashboard Cite

This review is dedicated to recent progress in the field of classical, interacting, massive spin-2 theories, with a focus on ghost-free bimetric theory. We will outline its history and its development as a nontrivial extension and generalisation of nonlinear massive gravity. We present a detailed discussion of the consistency proofs of both theories, before we review Einstein solutions to the bimetric equations of motion in vacuum as well as the resulting mass spectrum. We introduce couplings to matter and then discuss the general relativity and massive gravity limits of bimetric theory, which correspond to decoupling the massive or the massless spin-2 field from the matter sector, respectively. More general classical solutions are reviewed and the present status of bimetric cosmology is summarised. An interesting corner in the bimetric parameter space which could potentially give rise to a nonlinear theory for partially massless spin-2 fields is also discussed. Relations to higher-curvature theories of gravity are explained and finally we give an overview of possible extensions of the theory and review its formulation in terms of vielbeins.

show abstract

Section: General Propertiesmentioning

confidence: 91%

Section: General Propertiesmentioning

confidence: 99%

Recent developments in bimetric theory

Schmidt-May

Strauss

2016

J. Phys. A: Math. Theor.

198

240

View full text Add to dashboard Cite

show abstract

“…Therefore, although the existence of wormholes and bouncing cosmologies required violations of the NEC in general relativity, in modified gravity theories the NCC could be violated by material content satisfying the NEC. In that case, it is possible to define an effective stress-energy tensor putting together the modifications with respect to general relativity that violates the NEC [62,[70][71][72][73][74]. As this effective tensor is not associated with matter, there is no reason to require that it had some a priori characteristics.…”

Section: Limitations Of the Standard Energy Conditionsmentioning

confidence: 99%

Classical and Semi-classical Energy Conditions

Martín–Moruno

Visser

2017

Fundamental Theories of Physics

Self Cite

137

View full text Add to dashboard Cite

The standard energy conditions of classical general relativity are (mostly) linear in the stress-energy tensor, and have clear physical interpretations in terms of geodesic focussing, but suffer the significant drawback that they are often violated by semi-classical quantum effects. In contrast, it is possible to develop non-standard energy conditions that are intrinsically non-linear in the stress-energy tensor, and which exhibit much better well-controlled behaviour when semi-classical quantum effects are introduced, at the cost of a less direct applicability to geodesic focussing. In this chapter we will first review the standard energy conditions and their various limitations. (Including the connection to the Hawking-Ellis type I, II, III, and IV classification of stress-energy tensors). We shall then turn to the averaged, nonlinear, and semi-classical energy conditions, and see how much can be done once semi-classical quantum effects are included.

show abstract

“…Therefore, one can impose that the WEC be satisfied for the matter stressenergy tensor, but there is no reason why the energy density associated with the effective stress-energy tensor should be positive, since this tensor just encapsulates the modification with respect to GR [21,25]. Indeed, in some theories one can easily obtain T (eff) ab k a k b < 0; see, for example, [48,49]. Following this spirit, in alternative theories of gravity one can obtain geometries where the NCC is violated supported by a material content with a positive energy density as measured by any observer.…”

Section: Effective Phantom Behaviormentioning

confidence: 99%

Phantom singularities and their quantum fate: general relativity and beyond—a CANTATA COST action topic

2019

View full text Add to dashboard Cite

Cosmological observations allow the possibility that dark energy is caused by phantom fields. These fields typically lead to the occurrence of singularities in the late Universe. We review here the status of phantom singularities and their possible avoidance in a quantum theory of gravity. We first introduce phantom energy and discuss its behavior in cosmology. We then list the various types of singularities that can occur from its presence. We also discuss the possibility that phantom behavior is mimicked by an alternative theory of gravity. We finally address the quantum cosmology of these models and discuss in which sense the phantom singularities can be avoided.

show abstract

Null Energy Condition violations in bimetric gravity

Cited by 55 publications

References 50 publications

Recent developments in bimetric theory

Recent developments in bimetric theory

Classical and Semi-classical Energy Conditions

Phantom singularities and their quantum fate: general relativity and beyond—a CANTATA COST action topic

Contact Info

Product

Resources

About