Zobrazeno 1 - 10
of 122
pro vyhledávání: '"Hassan Firouzjahi"'
Publikováno v:
Journal of High Energy Physics, Vol 2021, Iss 6, Pp 1-24 (2021)
Abstract We present a scenario of vector dark matter production during inflation containing a complex inflaton field which is charged under a dark gauge field and which has a symmetry breaking potential. As the inflaton field rolls towards the global
Externí odkaz:
https://doaj.org/article/d89927779020482b801d73e4f834426a
Publikováno v:
Journal of High Energy Physics, Vol 2021, Iss 5, Pp 1-46 (2021)
Abstract Axion-like fields heavier than about 10 −27 eV are expected to oscillate in the radiation dominated epoch when the Hubble parameter drops below their mass. Considering the Chern-Simons coupling with a dark gauge boson, large amount of dark
Externí odkaz:
https://doaj.org/article/a271931d3fca41d7b848b066f3d56853
Publikováno v:
Journal of High Energy Physics, Vol 2021, Iss 1, Pp 1-33 (2021)
Abstract We study inflationary solution in an extension of mimetic gravity with the higher derivative interactions coupled to gravity. Because of the higher derivative interactions the setup is free from the ghost and gradient instabilities while it
Externí odkaz:
https://doaj.org/article/6c400e6ecd5b4fff97c53ad60fccd193
Publikováno v:
The Astrophysical Journal, Vol 948, Iss 1, p 48 (2023)
We study a model of inflation with multiple pseudo-scalar fields coupled to a U (1) gauge field through Chern–Simons interactions. Because of parity-violating interactions, one polarization of the gauge field is amplified, yielding to an enhanced c
Externí odkaz:
https://doaj.org/article/41fc315ab77341b28538533ee4ad1953
Autor:
Hassan Firouzjahi, Alireza Talebian
The spacetime inside the white hole is like an anisotropic cosmological background with the past singularity playing the role of a big bang singularity. The scale factor along the extended spatial direction is contracting while the scale factor along
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9fdfba14256da7886b9a95bb3a37f664
http://arxiv.org/abs/2210.15186
http://arxiv.org/abs/2210.15186
We study the effects of multiple transitions in the vacuum dark energy density on the $H_0$ tension problem. We consider a phenomenological model in which the vacuum energy density undergoes multiple transitions in the early as well as the late unive
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cbe0186a6bec245e1aaffecb43d53a30
http://arxiv.org/abs/2208.05583
http://arxiv.org/abs/2208.05583
Autor:
Hassan Firouzjahi
We study the quantum vacuum zero point energy in the Schwarzschild black hole as well as in the Nariai limit of the dS-Schwarzschild backgrounds. We show that the regularized vacuum energy density near the black hole and also in the Nariai setup matc
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2cb383d1f98c43360cfd3e112d703289
http://arxiv.org/abs/2205.06561
http://arxiv.org/abs/2205.06561
Publikováno v:
Physical Review D. 105
We revisit the model of axion inflation in the context of stochastic inflation and investigate the effects of the stochastic noises associated to the electromagnetic fields. Because of the parity violating interaction, one polarization of the gauge f
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::04e0ca78a59992d52a60cfde294d2a0b
https://doi.org/10.1103/physrevd.105.103516
https://doi.org/10.1103/physrevd.105.103516
Publikováno v:
Physical Review D. 105
In this paper, we extend the mimetic gravity to the multi-field setup with a curved field space manifold. The multi-field mimetic scenario is realized via the singular limit of the conformal transformation between the auxiliary and the physical metri
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a1f60b5797b8d118b16d4330babca134
https://doi.org/10.1103/physrevd.105.023529
https://doi.org/10.1103/physrevd.105.023529
We study a model of two-field ultra-slow-roll (USR) inflation bounded by a curve in the field space. Curvature perturbations and non-Gaussianities can be enhanced both during the USR phase and from the inhomogeneities at the boundary. We employ the f
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2232f8fb758e4d1a1b308729349c8153
http://arxiv.org/abs/2201.07258
http://arxiv.org/abs/2201.07258