PT Journal
AU Nadal-Gisbert, S
   Navarro-Salas, J
   Pla, S
TI Low-energy states and CPT invariance at the big bang
SO Physical Review D
JI Phys. Rev. D
PY 2023
BP 085018
EP 16pp
VL 107
IS 8
DI 10.1103/PhysRevD.107.085018
LA English
AB In this paper, we analyze the quantum vacuum in a radiation-dominated and CPT -invariant universe by further imposing the quantum states to be ultraviolet regular i.e., satisfying the Hadamard/adiabatic condition. For scalar fields, this is enforced by constructing the vacuum via the states of low-energy proposal. For spin -12 fields, we extend this proposal for a FLRW spacetime and apply it for the radiation-dominated and CPT -invariant universe. We focus on minimizing the smeared energy density around the big bang and give strong evidence that the resulting states satisfy the Hadamard/adiabatic condition. These states are then self -consistent candidates as effective big bang quantum vacuum from the field theory perspective.
ER