Quantum Field Theory In Curved Spacetime: Quant... Today

Quantum Field Theory in Curved Spacetime: Quantized Fields and Semiclassical Gravity

: In the early, rapidly expanding universe, time-varying gravitational fields can "excite" the vacuum, creating elementary particles that seed the large-scale structure of the universe. Robert Wald - Quantum Field Theory in Curved Spacetime

: The concept of a "particle" becomes local and observer-dependent. Different observers (e.g., one inertial and one accelerating) may disagree on whether a state contains particles or is a vacuum.

: An observer accelerating through a Minkowski vacuum will perceive it as a thermal bath of particles at a temperature proportional to their acceleration.

is a linear combination of both the old annihilation and creation operators:

: 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