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

: General curved backgrounds lack global Poincaré invariance and time-translation symmetry, making it impossible to define a unique, preferred vacuum state.

This framework predicts several landmark effects that bridge the gap between thermodynamics, gravity, and quantum mechanics: Quantum Field Theory in Curved Spacetime: Quant...

To relate the perspectives of different observers or the state of fields at different times in an expanding universe, physicists use : Field Decomposition : A scalar field is expanded into a set of basis modes with creation and annihilation operators Quantum Field Theory in Curved Spacetime: Quant...

) will contain a non-zero number of particles according to the second observer. 3. Key Phenomena Quantum Field Theory in Curved Spacetime: Quant...