Non-Locality and Late-Time Cosmic Acceleration from an Ultraviolet Complete Theory †

Narain, Gaurav; Li, Tianjun

doi:10.3390/universe4080082

Cited by 9 publications

(5 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For μ2 /χ 2 → 0 this results in a scale invariant effective action with constant coefficients f, B, λ, C and D. Such scale invariant gravitational actions (sometimes considered as classical) have been discussed in refs. [61,198,203].…”

Section: Dilaton Quantum Gravitymentioning

confidence: 99%

Quantum scale symmetry

Wetterich¹

2019

Preprint

106

View full text Add to dashboard Cite

Quantum scale symmetry is the realization of scale invariance in a quantum field theory. No parameters with dimension of length or mass are present in the quantum effective action. Quantum scale symmetry is generated by quantum fluctuations via the presence of fixed points for running couplings. As for any global symmetry, the ground state or cosmological state may be scale invariant or not. Spontaneous breaking of scale symmetry leads to massive particles and predicts a massless Goldstone boson. A massless particle spectrum follows from scale symmetry of the effective action only if the ground state is scale symmetric. Approximate scale symmetry close to a fixed point leads to important predictions for observations in various areas of fundamental physics.We review consequences of scale symmetry for particle physics, quantum gravity and cosmology. For particle physics, scale symmetry is closely linked to the tiny ratio between the Fermi scale of weak interactions and the Planck scale for gravity. For quantum gravity, scale symmetry is associated to the ultraviolet fixed point which allows for a non-perturbatively renormalizable quantum field theory for all known interactions. The interplay between gravity and particle physics at this fixed point permits to predict couplings of the standard model or other "effective low energy models" for momenta below the Planck mass. In particular, quantum gravity determines the ratio of Higgs boson mass and top quark mass. In cosmology, approximate scale symmetry explains the almost scale-invariant primordial fluctuation spectrum which is at the origin of all structures in the universe. The pseudo-Goldstone boson of spontaneously broken approximate scale symmetry may be responsible for dynamical dark energy and a solution of the cosmological constant problem.

show abstract

Section: Dilaton Quantum Gravitymentioning

confidence: 99%

Quantum scale symmetry

Wetterich¹

2019

Preprint

106

View full text Add to dashboard Cite

show abstract

“…In [21], the phenomenon is explained by the infrared corrections. Narain [22] predicts that an Ultraviolet Complete Theory leads to the expansion. A fascinating illustration can be seen in [23] where the expedited expansion occurs in the absence of DE.…”

Section: Introductionmentioning

confidence: 99%

Vacuum Energy in Saez-Ballester Theory and Stabilization of Extra Dimensions

Singh

2022

Universe

View full text Add to dashboard Cite

In this work, we study a spherically symmetric metric in 5D within the framework of Saez-Ballester Theory, where minimal dark energy-matter interaction occurs. We predict that the expanding isotropic universe will be progressively DE dominated. We estimate few values of the deceleration parameter, very close to the recently predicted values. We obtain the value of the DE EoS parameter as ω=−1. Additionally, we measure the value of the overall density parameter as Ω=0.97(≈1), in line with the notion of a close to or nearly (not exactly) flat universe. We predict that the model universe starts with the Big-Bang and ends at the Big Freeze singularity. In general, we cannot find conditions for stabilization of extra dimensions in general relativity, and all dimensions want to be dynamical. Here, we present two possible conditions to solve this stabilization problem in general relativity.

show abstract

“…Recently, nonlocal theories have been studied extensively in the context of ultraviolet modification of theories, where such non-local modifications may render theory UV finite or super-renormalizable [27,28]. Infrared non-locality is mostly studied in the context of cosmology to give an alternative explanation to the accelerated expansion of cosmological space-time [29][30][31][32][33][34][35][36]. Non-local theories have also been explored in the context of black-hole information loss paradox [37,38].…”

Section: Introductionmentioning

confidence: 99%

Non-local scalar field on deSitter and its infrared behaviour

Narain

Kajuri

2019

Physics Letters B

Self Cite

View full text Add to dashboard Cite

We investigate free non-local massless and massive scalar field on deSitter (dS) space-time. We compute the propagator for the non-local scalar field for the corresponding theories on flat and deSitter space-times. It is seen that for the non-local theory, the massless limit of massive propagator is smooth for both flat and deSitter. Moreover, this limit matches exactly with the massless propagator of the non-local scalar field for both flat and deSitter space-time. The propagator is seen to respect dS invariance. Furthermore, investigations of the non-local Green's function on deSitter for large time-like separation shows that the propagator has no infrared divergences. The dangerous infrared log-divergent contributions which arise is local massless theories are absent in the corresponding non-local version. Lack of infrared divergences in the propagator hints at the strong role non-localities may play in the dS infrared physics. This study suggest that non-locality can cure IR issues in deSitter. *

show abstract

Non-Locality and Late-Time Cosmic Acceleration from an Ultraviolet Complete Theory †

Cited by 9 publications

References 44 publications

Quantum scale symmetry

Quantum scale symmetry

Vacuum Energy in Saez-Ballester Theory and Stabilization of Extra Dimensions

Non-local scalar field on deSitter and its infrared behaviour

Contact Info

Product

Resources

About