Thermally induced photon splitting

Abstract

We calculate thermal corrections to the non-linear QED effective action for low-energy photon interactions in a background electromagnetic field. The high-temperature expansion shows that at $T \gg m$ the vacuum contribution is exactly cancelled to all orders in the external field except for a non-trivial two-point function contribution. The high-temperature expansion derived reveals a remarkable cancellation of infrared sensitive contributions. As a result photon-splitting in the presence of a magnetic field is suppressed in the presence of an electron-positron QED-plasma at very high temperatures. In a cold and dense plasma a similar suppression takes place. At the same time Compton scattering dominates for weak fields and the suppression is rarely important in physical situations.Comment: 15 pages, 2 ps figures, Late

Photon splitting in a strongly magnetized, charge-asymmetric plasma

“…According to Eqs. (18) and (19), the absorption rate of the channel γ 2 → γ 1 γ 1 can be presented as…”

“…[18,19] on the basis of the Euler-Heisenberg effective Lagrangian with taking account of the thermal corrections in the one-loop and two-loop approximation correspondingly. It was noted that in the low temperature limit the process γ → γγ could compete with the other absorption reactions such as the Compton scattering process.…”

“…Note that in Refs. [18][19][20] the effects of the photon dispersion in magnetized plasma were not taken into account. However, the situation may change significantly in the limit of a strong magnetic field and plasma.…”

From effective actions to actual effects

“…Let us now come to the results for the thermal effective action; at the one-loop level various exact representations are known for arbitrary values of temperature and field strength [11,12,13]. Here, we confine ourselves to some limiting cases.…”

“…Next, we turn to thermally induced photon splitting [13,14], motivated by the fact that strong magnetic fields and finite temperature (and density) may be encountered near compact astrophysical objects. The new feature of the thermal process is that the box graph with one coupling to the background field (see Fig.…”