scholarly journals Modified dispersion relations, inflation, and scale invariance

2018 ◽  
Vol 97 (4) ◽  
Author(s):  
Stefano Bianco ◽  
Victor Nicolai Friedhoff ◽  
Edward Wilson-Ewing
2010 ◽  
Vol 19 (12) ◽  
pp. 1905-1914 ◽  
Author(s):  
YAO LU ◽  
YUN-SONG PIAO

In this paper, inspired by the investigations on the theory of cosmological perturbations in Hořava–Lifshitz cosmology, we calculate the spectrum of primordial perturbation lead by a modified dispersion relation in proper time ω pro ~ kz/ap in power-law expansion/contraction background a ~ tn · z is the critical exponent and p is not necessarily equal to z · p = z is well-motivated by Hořava–Lifshitz gravity, and the cases with p ≠ z are generalizations beyond the scope. We discuss that for fixed z, if the spectrum is required to be scale-invariant, how should p depend on n. We conclude that there is always room for parameters for the generation of scale-invariant spectrum.


2011 ◽  
Vol 20 (05) ◽  
pp. 745-756 ◽  
Author(s):  
FRANCISCO DIEGO MAZZITELLI

We discuss the renormalization procedure for quantum scalar fields with modified dispersion relations in curved spacetimes. We consider two different ways of introducing modified dispersion relations: through the interaction with a dynamical temporal vector field, as in the context of the Einstein–Aether theory, and breaking explicitly the covariance of the theory, as in Hǒrava–Lifshitz gravity. Working in the weak field approximation, we show that the general structure of the counterterms depends on the UV behavior of the dispersion relations and on the mechanism chosen to introduce them.


2007 ◽  
Vol 24 (16) ◽  
pp. 3995-4008 ◽  
Author(s):  
F Girelli ◽  
S Liberati ◽  
R Percacci ◽  
C Rahmede

2009 ◽  
Vol 24 (32) ◽  
pp. 2579-2587 ◽  
Author(s):  
LUCA BOMBELLI ◽  
JOE HENSON ◽  
RAFAEL D. SORKIN

This paper concerns random sprinklings of points into Minkowski spacetime (Poisson processes). It proves that there exists no equivariant measurable map from sprinklings to spacetime directions (even locally). Therefore, if a discrete structure is associated to a sprinkling in an intrinsic manner, then the structure will not pick out a preferred frame, locally or globally. This implies that the discreteness of a sprinkled causal set will not give rise to "Lorentz breaking" effects like modified dispersion relations. Another consequence is that there is no way to associate a finite-valency graph to a sprinkling consistently with Lorentz invariance.


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