Speaker
Description
When quantizing theory in curved space-time, one can define vacuum state with respect to different timelike Killing vectors. In case of Schwarzschild space-time one usually considers Boulware, Unruh and Hartle-Hawking vacua, where the latter two use Kruskal null coordinates to define positive-frequency modes. Loop corrections to the occupation numbers and anomalous quantum averages are considered for scalar particles and it is shown that there are no corrections up to second order in coupling constant for Boulware and Hartle-Hawking vacua, but there are non-zero contributions in case of Unruh vacuum.