TY  - JOUR
AU  - del Rio, A.
AU  - Navarro-Salas, J.
AU  - Torrenti, F.
PY  - 2014
DA  - 2014//
TI  - Renormalized stress-energy tensor for spin-1/2 fields in expanding universes
T2  - Phys. Rev. D
JO  - Physical Review D
SP  - 084017
EP  - 15pp
VL  - 90
IS  - 8
PB  - Amer Physical Soc
AB  - We provide an explicit expression for the renormalized expectation value of the stress-energy tensor of a spin-1/2 field in a spatially flat Friedmann-Lemaitre-Robertson-Walker universe. Its computation is based on the extension of the adiabatic regularization method to fermion fields introduced recently in the literature. The tensor is given in terms of UV-finite integrals in momentum space, which involve the mode functions that define the quantum state. As illustrative examples of the method efficiency, we see how to compute the renormalized energy density and pressure in two interesting cosmological scenarios: a de Sitter spacetime and a radiation-dominated universe. In the second case, we explicitly show that the late-time renormalized stress-energy tensor behaves as that of classical cold matter. We also check that, if we obtain the adiabatic expansion of the scalar field mode functions with a similar procedure to the one used for fermions, we recover the well-known WKB-type expansion.
SN  - 1550-7998
UR  - http://arxiv.org/abs/1407.5058
UR  - https://doi.org/10.1103/PhysRevD.90.084017
DO  - 10.1103/PhysRevD.90.084017
LA  - English
N1  - WOS:000343773100003
ID  - delRio_etal2014
ER  -