Radiation of inertial scalar particles in the de Sitter universe

Abstract

We investigate the radiation of an inertial scalar particle evolving in a de Sitter expanding Universe. In the context of scalar QED the process is generated by the first order term in the perturbation theory expansion of the S-matrix. The partial transition probability is obtained and analysed, and soft-photon emission is found to dominate overall. It has been argued that an inertial particle evolving in dS spacetime loses physical momentum just as a decelerated particle in Minkowski space does. It is thus expected that an inertial charge will radiate in a similar way.We investigate the radiated energy and make a qualitative comparison of the angular distribution of the energy with the radiation pattern in the latter case.

Quantum radiation from an inertial scalar charge evolving in the de Sitter universe: Weak-field limit

“…This is in agreement with ref. [16] and with our previous results [7], in that the radiation vanishes both in the flat limit ( and for comoving observers ( .…”

“…This problem will be discussed in a forthcoming paper. The transition probability and radiated energy for this emission process was obtained in a previous paper [7]. Here we consider the energy radiated in the weak-field (small expansion parameter) limit.…”

“…The F4 function in eq. (9) is a power series with coefficients inversely proportional to , thus in the flat limit F4 Numerical calculations have shown that this approximation is very good for Using the above notations the partial probability becomes [7]: FIGURE 1. The transition probability ( ) with the approximate analytical formula (black lines) plotted against the numerically evaluated probability (dashed lines), as a function of , for different values of the angle between the initial and final scalar particle momenta ( -left, -right).…”

Quantum Larmor radiation in de Sitter spacetime

“…1a was obtained in Ref. [19] by one of the authors, and it equals 2 Note that momentum conservation constrains the momenta p + k = p in the first, and k + q + q = 0 in the second process.…”

Late-time quantum radiation by a uniformly accelerated detector in de Sitter spacetime

“…The photon emission of a spinless electric charge in de Sitter spacetime has been calculated in Refs. [36,37], along the same line of Refs. [38,39] using the time-dependent perturbation theory in the in-out formalism.…”