Oleksandr Sobol

Magnetogenesis in Higgs-Starobinsky inflation

In the framework of mixed Higgs-Starobinsky inflation, we consider the generation of Abelian gauge fields due to their nonminimal coupling to gravity (in two different formulations of gravity-metric and Palatini). We couple the gauge-field invariants F mu ...

American Physical Society2022

Hypermagnetogenesis from axion inflation: Model-independent estimates

Oleksandr Sobol

Axion inflation coupled to the Standard Model (SM) hypercharge gauge sector represents an attractive scenario for the generation of primordial hypemiagnetic fields. The description of this scenario is, however, complicated by the Schwinger effect, which gi ...

American Physical Society2022

Equilibration of the chiral asymmetry due to finite electron mass in electron-positron plasma

Oleksandr Sobol

We calculate the rate of collisional decay of the axial charge in an ultrarelativistic electron-positron plasma, also known as the chirality flipping rate. We find that contrary to the existing estimates, the chirality flipping rate appears already in the ...

American Physical Society2021

Gauge-field production during axion inflation in the gradient expansion formalism

Oleksandr Sobol

We study the explosive production of gauge fields during axion inflation in a novel gradient expansion formalism that describes the time evolution of a set of bilinear electromagnetic functions in position space. Based on this formalism, we are able to sim ...

American Physical Society2021

Generation of an electromagnetic field nonminimally coupled to gravity during Higgs inflation

Oleksandr Sobol

In the framework of Higgs inflation, we consider the electromagnetic field nonminimally coupled to gravity via the parity-preserving proportional to RF2 and parity-violating proportional to RF (F) over tilde terms. Using the perturbation theory to the lead ...

American Physical Society2021

Schwinger production of scalar particles during and after inflation from the first principles

Oleksandr Sobol

By using the first-principles approach, we derive a system of three quantum kinetic equations governing the production and evolution of charged scalar particles by an electric field in an expanding universe. Analyzing the ultraviolet asymptotic behavior of ...

American Physical Society2020

Gradient expansion formalism for magnetogenesis in the kinetic coupling model

Oleksandr Sobol

In order to describe magnetogenesis during inflation in the kinetic coupling model, we utilize a gradient expansion which is based on the fact that only long-wavelength (superhorizon) modes undergo amplification. For this purpose, we introduce a set of fun ...

American Physical Society2020

Backreaction of electromagnetic fields and the Schwinger effect in pseudoscalar inflation magnetogenesis

Oleksandr Sobol

We study magnetogenesis in axionlike inflation driven by a pseudoscalar field phi coupled axially to the electromagnetic (EM) field (beta/M-p)phi F-mu nu(F) over tilde mu nu with dimensionless coupling constant beta. A set of equations for the inflaton fie ...

American Physical Society2019

Kinetic approach to the Schwinger effect during inflation

Oleksandr Sobol

Using the kinetic approach, we study the impact of the charged particle dynamics due to the Schwinger effect on the electric field evolution during inflation. As a simple model of the electric field generation, we consider the kinetic coupling of the elect ...

American Physical Society2019

Oleksandr Sobol

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Magnetogenesis in Higgs-Starobinsky inflation

Hypermagnetogenesis from axion inflation: Model-independent estimates

Equilibration of the chiral asymmetry due to finite electron mass in electron-positron plasma

Gauge-field production during axion inflation in the gradient expansion formalism

Generation of an electromagnetic field nonminimally coupled to gravity during Higgs inflation

Evolution of the Primordial Axial Charge across Cosmic Times

Schwinger production of scalar particles during and after inflation from the first principles

Gradient expansion formalism for magnetogenesis in the kinetic coupling model

Backreaction of electromagnetic fields and the Schwinger effect in pseudoscalar inflation magnetogenesis

Kinetic approach to the Schwinger effect during inflation

Magnetogenesis in Higgs-Starobinsky inflation

Hypermagnetogenesis from axion inflation: Model-independent estimates

Gauge-field production during axion inflation in the gradient expansion formalism

Gradient expansion formalism for magnetogenesis in the kinetic coupling model

Generation of an electromagnetic field nonminimally coupled to gravity during Higgs inflation

Evolution of the Primordial Axial Charge across Cosmic Times

Schwinger production of scalar particles during and after inflation from the first principles

Backreaction of electromagnetic fields and the Schwinger effect in pseudoscalar inflation magnetogenesis

Kinetic approach to the Schwinger effect during inflation

Equilibration of the chiral asymmetry due to finite electron mass in electron-positron plasma