DSR as an explanation of cosmological structure

Magueijo, João

doi:10.1088/0264-9381/25/20/202002

Cited by 29 publications

(53 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The minimal bimetric theory leads to scale-invariant perturbations but it is also possible to obtain deviations from strict scale-invariance, subject to consistency relations involving the 3-point function [29,30]. It is also possible to implement this mechanism via deformed dispersion relations [31], as we now review.…”

Section: Cosmological Perturbationsmentioning

confidence: 98%

“…In particular it is associated with Hořava-Lifshitz (HL) theory for an anisotropic scaling with dynamical critical exponent z = 3, a theory known to be power-counting renormalisable [4]. Before the advent of HL theory it was known [31] that this dispersion relation leads to a scale-invariant spectrum of density fluctuations without appealing to inflation. This important remark was later picked up in the context of HL theory [32], where it was noted that the result is independent of the assumption of detailed balance.…”

Section: Pervasiveness Of Scale-invariance For Ds =mentioning

confidence: 99%

“…The modes can then be appropriately normalized and their vacuum fluctuations computed, and followed as the modes leave the horizon. In [31] this exercise was performed, solving (3) in terms of Bessel functions for all values of γ and w. It was found that γ = 2 leads to n S = 1 universally. Here, instead of repeating the more rigorous treatment, we explain qualitatively the pervasiveness of scale-invariance for this dispersion relation.…”

Section: Pervasiveness Of Scale-invariance For Ds =mentioning

confidence: 99%

See 2 more Smart Citations

Dimensional reduction in the sky

et al. 2013

Self Cite

View full text Add to dashboard Cite

We explore the cosmological implications of a mechanism found in several approaches to quantum-gravity, whereby the spectral dimension of spacetime runs from the standard value of 4 in the infrared (IR) to a smaller value in the ultraviolet (UV). Specifically, we invoke the picture where the phenomenon is associated with modified dispersion relations. With minimal assumptions, we find that UV behaviour leading to 2 spectral dimensions results in an exactly scale-invariant spectrum of vacuum scalar and tensor fluctuations, regardless of the equation of state. The fluctuation production mechanism is analogous to the one known for varying speed of sound/light models and, unlike in inflation, the spectrum is already scale-invariant before leaving the horizon, remaining so after freeze-in. In the light of Planck's recent results we also discuss scenarios that break exact scale-invariance, such as the possibility that the spectral dimension runs down to a value slightly higher than 2, or runs down to 2 but with an extremely slow transient. We further show that the tensor to scalar ratio is fixed by the UV ratio between the speed of gravity and the speed of light. Not only does our model not require inflation, but at its most minimal it seems incompatible with it. In contrast, we find that running spectral dimensions can improve the outlook of the cyclic/ekpyrotic scenario, solving the main problems present in its simplest and most appealing realisations.

show abstract

Section: Cosmological Perturbationsmentioning

confidence: 98%

Section: Pervasiveness Of Scale-invariance For Ds =mentioning

confidence: 99%

Section: Pervasiveness Of Scale-invariance For Ds =mentioning

confidence: 99%

See 1 more Smart Citation

Dimensional reduction in the sky

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nonetheless there has been ongoing interest in whether the speed of light really is invariant (Albrecht & Magueijo, 1999;Barrow & Magueijo, 1999;Bassett, Liberati, Molina-Paris, & Visser, 2000;Clayton & Moffat, 2003;Magueijo, 2001Magueijo, , 2003Magueijo, , 2008Moffat, 2005;Singha & Debnath, 2007;Sisterna, 2011;Szydlowski & Krawiec, 2003;Unzicker, 2009). The primary purpose of these endeavours has been to explore for new physics at deeper levels, with a particular interest in quantum-gravity.…”

Section: Variable Speed Of Light Theoriesmentioning

confidence: 99%

Speed of Light as an Emergent Property of the Fabric

Pons¹,

Pons²,

Pons³

2016

APR

View full text Add to dashboard Cite

Problem-The theory of Relativity is premised on the constancy of the speed of light (c) in-vacuo. While no empirical evidence convincingly shows the speed to be variable, nonetheless from a theoretical perspective the invariance is an assumption. Need-It is possible that the evidence could be explained by a different theory. Approach-A non-local hidden-variable (NLHV) solution, the Cordus particule theory, is applied to identify the causes of variability in the fabric density, and then show how this affects the speed of light. Findings-Under these assumptions the speed of light is variable (VSL), being inversely proportional to fabric density. This is because the discrete fields of the photon interact dynamically with the fabric and therefore consume frequency cycles of the photon. The fabric arises from aggregation of fields from particles, which in turn depends on the proximity and spatial distribution of matter. Results disfavour the universal applicability of the cosmological principle of homogeneity and isotropy of the universe. Originality-The work proposes causal mechanisms for VSL, which have otherwise been challenging to ascertain. Uniquely, this theory identifies fabric density as the dependent variable. In contrast, other VSL models propose that c varies with time or some geometric-like scale, but struggle to provide plausible reasons for that dependency. This theory also offers a conceptually simply way to reconcile the refraction of light in both gravitational situations and optical materials.

show abstract

“…They in fact describe effects that are quite generically expected in quantum gravity research [3,4] (and in particular have been explicitly shown to characterize 3D quantum gravity [5,6]) without introducing preferred frames and so evading the strong constraints on Lorentz invariance violations. Modified dispersion relations could produce observable phenomenology in the context of astrophysics [7][8][9][10][11] and there is also increasing evidence that they could be relevant in the early Universe [12][13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Kinematics of particles with quantum-de Sitter-inspired symmetries

Barcaroli¹,

Gubitosi

2016

Phys. Rev. D

View full text Add to dashboard Cite

We present the first detailed study of the kinematics of free relativistic particles whose symmetries are compatible with the ones described by a quantum deformation of the de Sitter algebra, known as q-de Sitter Hopf algebra. In such algebra, the quantum deformation parameter is a function of the Planck length l and the de Sitter radius H −1 , such that when the Planck length vanishes, the algebra reduces to the de Sitter algebra, while when the de Sitter radius is sent to infinity, one recovers the κ-Poincaré Hopf algebra. In the first limit, the picture is that of a particle with trivial momentum space geometry moving on de Sitter spacetime; in the second one, the picture is that of a particle with de Sitter momentum space geometry moving on Minkowski spacetime. When both the Planck length and the inverse of the de Sitter radius are nonzero, effects due to spacetime curvature and nontrivial momentum space geometry are both present and affect each other. The particles' motion is then described in a full phase-space picture. We find that redshift effects that are usually associated with spacetime curvature become energy dependent. Also, the energy dependence of the particles' travel times that is usually associated with momentum space nontrivial properties is modified in a curvature-dependent way.

show abstract

DSR as an explanation of cosmological structure

Cited by 29 publications

References 46 publications

Dimensional reduction in the sky

Dimensional reduction in the sky

Speed of Light as an Emergent Property of the Fabric

Kinematics of particles with quantum-de Sitter-inspired symmetries

Contact Info

Product

Resources

About