Quantum Field Theory in Curved Spacetime (QFTCS) is a "hybrid" framework where matter fields are treated according to quantum principles, but the gravitational background is described classically by a fixed spacetime metric gμνg sub mu nu end-sub
: Because global constructs like Fourier transforms are unavailable, QFTCS must be formulated locally using quantum field operators rather than particle counts. 2. Mathematical Framework: Bogoliubov Transformations Quantum Field Theory in Curved Spacetime: Quant...
is a linear combination of both the old annihilation and creation operators: Quantum Field Theory in Curved Spacetime (QFTCS) is
: A second observer might decompose the same field using a different basis and operators Mixing : The new annihilation operator Quantum Field Theory in Curved Spacetime: Quant...