## Quantum Excitations in Time-Dependent Backgrounds    [PDF]

Matthew Kolopanis, Tanmay Vachaspati
We give a technique for calculating the occupation number of quantum fields in time-dependent backgrounds by using the relation between one-dimensional {\em quantum} oscillators and two-dimensional {\em classical} oscillators. We illustrate our method by giving closed analytical results for the time-dependent spectrum of occupation numbers during gravitational collapse in 3+1 dimensions.
View original: http://arxiv.org/abs/1302.1449