In Lecture 5, we discussed the basics of QFT in curved space. Since, in a general spacetime, there is no canonical choice of a time coordinate, the notion of "particles" becomes observer-dependent. We discussed how the physics of two different observers, using a different basis of mode functions, was related by Bogoliubov transformations. We then started to apply this formalism to understand how flat space appears for accelerated observers by quantizing a free-field in Rindler coordinates.

lecture_5_serc_school.pdf