146 research outputs found
Metric-Affine Myrzakulov Gravity Theories
In this paper, we review the so-called Myrzakulov Gravity models (MG-N, with N = I, II, …, VIII) and derive their respective metric-affine generalizations (MAMG-N), discussing also their particular sub-cases. The field equations of the theories are obtained by regarding the metric tensor and the general affine connection as independent variables. We then focus on the case in which the function characterizing the aforementioned metric-affine models is linear and consider a Friedmann-Lemaître–Robertson–Walker background to study cosmological aspects and applications. Historical motivation for this research is thoroughly reviewed and specific physical motivations are provided for the aforementioned family of alternative theories of gravity
Evading Lyth bound in models of quintessential inflation
Quintessential inflation refers to an attempt to unify inflation and
late-time cosmic acceleration using a single scalar field. In this letter we
consider two different classes of quintessential inflation, one of which is
based upon a Lagrangian with non-canonical kinetic term and a steep exponential potential while the second
class uses the concept of steep brane world inflation. We show that in both
cases the Lyth bound can be evaded, despite the large tensor-to-scalar ratio of
perturbations. The post-inflationary dynamics is consistent with
nucleosynthesis constraint in these cases.Comment: 6 Latex pages, no figures, reference updated and typos corrected, To
appear in PL
Holographic Complexity and Fidelity Susceptibility as Holographic Information Dual to Different Volumes in AdS
The holographic complexity and fidelity susceptibility have been defined as
new quantities dual to different volumes in AdS. In this paper, we will use
these new proposals to calculate both of these quantities for a variety of
interesting deformations of AdS. We obtain the holographic complexity and
fidelity susceptibility for an AdS black hole, Janus solution and a solution
with cylindrically symmetry, an inhomogeneous background and a hyperscaling
violating background. It is observed that the holographic complexity depends on
the size of the subsystem for all these solutions and the fidelity
susceptibility does not have any such dependence.Comment: Slighly updated version. Accepted for publication in Phys. Letters
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