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Quantum cosmology of the Big Rip: Within GR and in a modified theory of gravity
(MDPI, 2017-04-14)
Quantum gravity is the theory that is expected to successfully describe systems that are under strong gravitational effects while at the same time being of an extreme quantum nature. When this principle is applied to the ...
Cosmological Perturbations in Phantom Dark Energy Models
(MDPI, 2017-03-06)
The CDM paradigm, characterised by a constant equation of state w = -1 for dark energy, is the model that better fits observations. However, the same observations strongly support the possibility of a dark energy content ...
The Mimetic Born-Infeld Gravity: The Primordial Cosmos and Spherically Symmetric Solutions
(MDPI, 2017-11-27)
The Eddington-inspired-Born-Infeld (EiBI) model is reformulated within the mimetic approach. In the presence of a mimetic field, the model contains non-trivial vacuum solutions. We study a realistic primordial vacuum ...
Doomsdays in a modified theory of gravity: a classical and a quantum approach
(Elsevier, 2017-09-10)
By far cosmology is one of the most exciting subject to study, even more so with the current bulk of observations we have at hand. These observations might indicate different kinds of doomsdays, if dark energy follows ...
Phantom dark ghost in Einstein–Cartan gravity
(Springer, 2017-05-03)
A class of dynamical dark energy models is constructed through an extended version of fermion fields corresponding to phantom dark ghost spinors, which are spin 1/2 with mass dimension 1. We find that if these spinors ...
Vacuum state of the Dirac field in de Sitter space and entanglement entropy
(Springer, 2017-03-13)
We compute the entanglement entropy of a free massive Dirac field between two causally disconnected open charts in de Sitter space. We first derive the Bunch-Davies vacuum mode functions of the Dirac field. We find there ...
Lower bounds on quantum metrological precision
(2017-05-19)
Lan honek metrologia kuantikoaren baitan egindako hainbat ikerketa biltzen ditu tesi moduan. Aurkezten dudan ikerlan hau, Zientzia eta Teknologia Kuantikoko masterra bukatu ondoren, azkeneko lau urte hauetan Prof. Géza ...
On the universality of MOG weak field approximation at galaxy cluster scale
(Elsevier, 2017-07-10)
In its weak field limit, Scalar-tensor-vector gravity theory introduces a Yukawa-correction to the gravitational potential. Such a correction depends on the two parameters, alpha which accounts for the modification of the ...
Physical cosmology with complete samples of massive clusters of galaxies
(2017-07-13)
El objetivo central de esta tesis ha sido usar grandes conjuntos de cúmulos de galaxias, las estructuras gravitacionalmente ligadas más masivas del Universo, para realizar medidas de distintos fenómenos que tienen su origen ...
Entanglement and extreme spin squeezing of unpolarized states
(IOP Publishing, 2017-01-20)
We present criteria to detect the depth of entanglement in macroscopic ensembles of spin-j particles using the variance and second moments of the collective spin components. The class of states detected goes beyond traditional ...