Faculty of Mathematics, Physics
and Informatics
Comenius University Bratislava

Seminar of Theoretical Physics - Adam Smetana, Mariia Petropavlova (23.11.2021)

Tuesday 23.11.2021, at 14:00 hod., Lecture room F2/125

18. 11. 2021 14.10 hod.
By: Peter Maták

Adam Smetana (Institute of Experimental and Applied Physics, CTU in Prague):
Hearing solar wind by space-based gravitational wave antennas

Recently we have identified a possible source of noise for the space-based gravitational wave antennas, in particular for the Laser Interferometer Space Antenna (LISA), caused by time variations of the refractive index of the interplanetary space due to variations in the electron number density of the solar wind. We will present an update of the analysis.


Mariia Petropavlova (Institute of Experimental and Applied Physics, CTU in Prague):
Corrections to the photon index of refraction due to neutral Dirac fermions with magnetic dipole moment

One of the Big Bang Cosmology predictions tells us that the Universe is filled with a background of neutrinos, analogous to the cosmic microwave background. If neutrinos have a magnetic moment, then photons passing through the CNB should experience interactions with these relic neutrinos. That would result in the correction to the corresponding photon index of refraction. It is our goal to estimate the size of the CNB correction to the photon index of refraction and its dependency on the energy of the photon beam. We present here our first step when we assume a medium made of neutral Dirac fermions with magnetic dipole moment only. The effect is calculated as a quantum loop correction to the photon polarization tensor using thermal quantum field theory and its real-time formalism. We analyze two benchmark cases: The first case is analogous to the CNB medium, where we show a zero effect. The second case is analogous to a fully degenerate neutron component of neutron star, where we find either zero or non-zero effect depending on the particular values of parameters.