Zobrazeno 1 - 10
of 111
pro vyhledávání: '"Rasanen, Syksy"'
Autor:
Hassan, Ali, Rasanen, Syksy
We consider the Chern-Simons term coupled to the inflaton in the Palatini formulation of general relativity. In contrast to the metric formulation, here the Chern-Simons term affects also the background evolution. We approximately solve for the conne
Externí odkaz:
http://arxiv.org/abs/2408.14983
Publikováno v:
Phys. Rev. Lett. 133, 121403 (2024)
We study the formation of primordial black holes (PBH) with ultra-slow-roll inflation when stochastic effects are important. We use the $\Delta N$ formalism and simplify the stochastic equations with an analytical constant-roll approximation. Conside
Externí odkaz:
http://arxiv.org/abs/2312.12911
Autor:
Nezhad, Hamed Bouzari, Rasanen, Syksy
Publikováno v:
JCAP02(2024)009
We study models where a scalar field has derivative and non-derivative couplings to the Ricci tensor and the co-Ricci tensor with a view to inflation. We consider both the metric formulation and the Palatini formulation. In the Palatini case, the cou
Externí odkaz:
http://arxiv.org/abs/2307.04618
Autor:
Annala, Jaakko, Rasanen, Syksy
Publikováno v:
JCAP04(2023)014 [Erratum: JCAP08(2023)E02]
We study the stability of theories where the gravitational action has arbitrary algebraic dependence on the three first traces of the Riemann tensor: the Ricci tensor, the co-Ricci tensor, and the homothetic curvature tensor. We collectively call the
Externí odkaz:
http://arxiv.org/abs/2212.09820
Autor:
Rasanen, Syksy, Verbin, Yosef
Publikováno v:
Open Journal of Astophysics, Vol. 6, 2023, January 26, 2023 IST
We consider a formulation of gauge field theory where the gauge field $A_\alpha$ and the field strength $F_{\alpha\beta}$ are independent variables, as in the Palatini formulation of gravity. For the simplest gauge field action, this is known to be e
Externí odkaz:
http://arxiv.org/abs/2211.15584
Implications of stochastic effects for primordial black hole production in ultra-slow-roll inflation
Publikováno v:
JCAP05(2022)027
We study the impact of stochastic noise on the generation of primordial black hole (PBH) seeds in ultra-slow-roll (USR) inflation with numerical simulations. We consider the non-linearity of the system by consistently taking into account the noise de
Externí odkaz:
http://arxiv.org/abs/2111.07437
Publikováno v:
JHEP06(2022)164
We calculate the tree-level amplitudes for electrically neutral $2\to2$ scattering for the Standard Model Higgs doublet non-minimally coupled to the Ricci scalar. We consider both the metric and the Palatini formulation of gravity. We find the partia
Externí odkaz:
http://arxiv.org/abs/2111.05621
Autor:
Koksbang, Sofie Marie, Rasanen, Syksy
Publikováno v:
JCAP04(2022)030
Light propagation in cosmology is usually studied in the geometrical optics approximation which requires the spacetime curvature to be much smaller than the light wavenumber. However, for non-fuzzy particle dark matter the curvature is concentrated i
Externí odkaz:
http://arxiv.org/abs/2108.06163
Autor:
Annala, Jaakko, Rasanen, Syksy
Publikováno v:
JCAP09(2021)032
We study inflation with the most general non-degenerate gravitational action that depends on the symmetric part of the Ricci tensor coupled to a scalar field in the Palatini formulation of gravity. We use field redefinitions to shift the effect of th
Externí odkaz:
http://arxiv.org/abs/2106.12422
Publikováno v:
Phys. Rev. Lett. 127, 101302 (2021)
We consider quantum diffusion in ultra-slow-roll (USR) inflation. Using the $\Delta N$ formalism, we present the first stochastic calculation of the probability distribution $P(\mathcal{R})$ of the curvature perturbation during USR. We capture the no
Externí odkaz:
http://arxiv.org/abs/2012.06551