Probing interaction in the dark sector

Abstract

A phenomenological attempt at alleviating the so-called coincidence problem is to allow the dark matter and dark energy to interact. By assuming a coupled quintessence scenario characterized by an interaction parameter $\epsilon$, we investigate the precision in the measurements of the expansion rate $H(z)$ required by future experiments in order to detect a possible deviation from the standard $\Lambda$CDM model ($\epsilon = 0$). We perform our analyses at two levels, namely: through Monte Carlo simulations based on $\epsilon$CDM models, in which $H(z)$ samples with different accuracies are generated and through an analytic method that calculates the error propagation of $\epsilon$ as a function of the error in $H(z)$. We show that our analytical approach traces simulations accurately and find that to detect an interaction {using $H(z)$ data only, these must reach an accuracy better than 1%.Comment: 4 pages, 3 figures, LaTe

Renormalized vacuum polarization on rotating warpedAdS3black holes

“…The dimensionless coupling ν ∈ (1, ∞) is the warp factor, and in the limit ν → 1 the above metric reduces to the metric of the BTZ black hole in a rotating frame. More details about this black hole solution can be found in [13,17,[24][25][26][27][28][29]. Here, we just describe a few relevant features.…”

“…In this setting, the matter field equations can be solved in terms of hypergeometric functions, which considerably simplify the technical issues in comparison with the Kerr spacetime. These black hole solutions are known to be classically stable to massive scalar field perturbations and, in particular, classical superradiance does not give rise to superradiant instabilities [17]. In this paper, we study a quantum scalar field on this black hole spacetime.…”

“…In this paper we introduce a similar mirror on the (2 + 1)-dimensional spacelike stretched black hole, and we consider the similar Hartle-Hawking state inside this mirror. This (2 + 1)-dimensional Hartle-Hawking state is known to be free of superradiant instabilities for massless as well as massive fields [17].…”

On detecting interactions in the dark sector withH(z)data

“…In [31] it was investigated for the specific Ansatz Q 1a with w = −1. Here we extend that analysis for the models described in Sect.…”

“…To allow a direct and unambiguous forecast we compute the average of the relative H(z) error, δH/H, over redshift [Eq. 5 of [31]]:…”