Hořava gravity with mixed derivative terms

Colombo, Mattia; Gümrükçüoğlu, A. Emir; Sotiriou, Thomas P.

doi:10.1103/physrevd.91.044021

Cited by 30 publications

(45 citation statements)

References 64 publications

(98 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Generically, the operators of the form (2.22) may compromise power counting renormalizability of the Hořava-Lifshitz gravity [64][65][66]. Therefore, they have been omitted in the original action (2.1).…”

Section: Jhep06(2016)020mentioning

confidence: 99%

Living with ghosts in Hořava-Lifshitz gravity

Ramazanov

Arroja

Celoria

et al. 2016

J. High Energ. Phys.

View full text Add to dashboard Cite

Abstract:We consider the branch of the projectable Hořava-Lifshitz model which exhibits ghost instabilities in the low energy limit. It turns out that, due to the Lorentz violating structure of the model and to the presence of a finite strong coupling scale, the vacuum decay rate into photons is tiny in a wide range of phenomenologically acceptable parameters. The strong coupling scale, understood as a cutoff on ghosts' spatial momenta, can be raised up to Λ ∼ 10 TeV. At lower momenta, the projectable Hořava-Lifshitz gravity is equivalent to General Relativity supplemented by a fluid with a small positive sound speed squared (10 −42 ) c 2 s 10 −20 , that could be a promising candidate for the Dark Matter. Despite these advantages, the unavoidable presence of the strong coupling obscures the implementation of the original Hořava's proposal on quantum gravity. Apart from the Hořava-Lifshitz model, conclusions of the present work hold also for the mimetic matter scenario, where the analogue of the projectability condition is achieved by a non-invertible conformal transformation of the metric.

show abstract

Section: Jhep06(2016)020mentioning

confidence: 99%

Living with ghosts in Hořava-Lifshitz gravity

Ramazanov

Arroja

Celoria

et al. 2016

J. High Energ. Phys.

View full text Add to dashboard Cite

show abstract

“…The resulting theory actually contains terms other than the ð∇ i K jk Þ 2 terms considered in Ref. [25]. Excluding these new terms would require unjustified finetuning.…”

Section: Introductionmentioning

confidence: 98%

“…[25], the contributions of all terms of the form ð∇ i K jk Þ 2 were studied. In this extension, all dispersion relations in the UV now become of the type ω 2 ∝ k 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Although for the standard Hořava gravity, this is not enough for powercounting renormalizability, Ref. [25] argued that in the presence of mixed-derivative terms, the UV scaling relation (1) is modified, and for the new power counting, these dispersion relations provide sufficient momentum suppressions in the amplitudes. Starting from modified anisotropic scaling rules, the fundamental basis for generic mixedderivative extensions were introduced in Ref.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Uninvited guest in mixed derivative Hořava gravity

et al. 2016

Self Cite

View full text Add to dashboard Cite

We revisit the mixed-derivative extension of Hořava gravity which was designed to address the naturalness problems of the standard theory in the presence of matter couplings. We consider the minimal theory with mixed-derivative terms that contain two spatial and two temporal derivatives. Including all terms compatible with the (modified) scaling rules and the foliation-preserving diffeomorphisms, we calculate the dispersion relations of propagating modes. We find that the theory contains four propagating degrees of freedom, as opposed to three in the standard Hořava gravity. The new degree of freedom is another scalar graviton, and it is unstable at low energies. Our result brings tension to the Lorentz-violation suppression mechanism that relies on separation of scales.

show abstract

“…Then, Lorentz violation is transmitted to matter only through loops with gravitons which are suppressed. However, the departure from the homogeneous Lifshitz scaling in the UV required by this approach can compromise the high-energy properties of the theory [27].…”

Section: Introductionmentioning

confidence: 99%