Zobrazeno 1 - 10
of 177
pro vyhledávání: '"Kamenshchik, Alexander Yu."'
Autor:
Casadio, Roberto, Chataignier, Leonardo, Kamenshchik, Alexander Yu., Pedro, Francisco G., Tronconi, Alessandro, Venturi, Giovanni
We make a conceptual overview of a particular approach to the initial-value problem in canonical gauge theories. We stress how the first-class phase-space constraints may be relaxed if we interpret them as fixing the values of new degrees of freedom.
Externí odkaz:
http://arxiv.org/abs/2402.12437
Autor:
Dimakis, Nikolaos, Duffy, Kevin, Giacomini, Alex, Kamenshchik, Alexander Yu., Leon, Genly, Paliathanasis, Andronikos
We investigate the impact of conformal transformations on the physical properties of solution trajectories in nonmetricity gravity. Specifically, we explore the phase-space and reconstruct the cosmological history of a spatially flat Friedmann-Lema\^
Externí odkaz:
http://arxiv.org/abs/2312.11208
We analyze the consequences of different evolutions of the Hubble parameter on the spectrum of scalar inflationary perturbations. The analysis is restricted to inflationary phases described by a transient evolution, when uncommon features arise in th
Externí odkaz:
http://arxiv.org/abs/2301.04477
We discuss applications of perturbative quantum gravity in the theory of very early quantum Universe and quantum cosmology. Consistency of the theoretical formalism for quantum effects of matter and correspondence with observational status of modern
Externí odkaz:
http://arxiv.org/abs/2212.13077
In the context of canonical quantum gravity, we consider the effects of a non-standard expression for the gravitational wave function on the evolution of inflationary perturbations. Such an expression and its effects may be generated by a sudden vari
Externí odkaz:
http://arxiv.org/abs/2210.04927
We consider a procedure of elimination of cosmological singularities similar to that suggested in the recent paper by Simpson and Visser for the construction of regular black holes. It is shown that by imposing a non-singular cosmological evolution w
Externí odkaz:
http://arxiv.org/abs/2208.02280
We investigate a model of gravitational collapse of matter inhomogeneities where the latter are modelled as Bianchi type IX (BIX) spacetimes. We found that this model contains, as limiting cases, both the standard spherical collapse model and the Zel
Externí odkaz:
http://arxiv.org/abs/2112.01869
Publikováno v:
Eur. Phys. J. C 82 (2022) no.4, 345
We examine long-wavelength correlation functions of massive scalar fields in de Sitter spacetime. For the theory with a quartic self-interaction, the two-point function is calculated up to two loops. Comparing our results with the Hartree-Fock approx
Externí odkaz:
http://arxiv.org/abs/2109.05625
Publikováno v:
Universe 7, 219 (2021)
We analyze the issue of dynamical evolution and time in quantum cosmology. We emphasize the problem of choice of phase space variables that can play the role of a time parameter in such a way that for expectation values of quantum operators the class
Externí odkaz:
http://arxiv.org/abs/2107.00917
Autor:
Dimakis, Nikolaos, Duffy, Kevin J., Giacomini, Alex, Kamenshchik, Alexander Yu., Leon, Genly, Paliathanasis, Andronikos
Publikováno v:
In Physics of the Dark Universe May 2024 44