Davies-Unruh like effect in the radiation dominated early Universe

Sujoy Modak (U. de Colima)

RESUMEN: In this talk I will introduce new geometric and field theoretic aspects of the radiation dominated universe (RDU). First on the geometric side we shall show that a conformal transformation of the FRW coordinates takes the RDU into a spherically symmetric form composed of two patches for the sub-Hubble and super-Hubble regions. I shall briefly discuss some interesting features of these coordinates. Then, in the field theory side, I will show that there exists a new unitarily inequivalent field quantization for massless scalar fields and introduce a new vacuum state called the T-vacuum. The existence of this T-vacuum would then imply a Davies-Unruh type effect for particle creation in the frame of cosmological and comoving observers.