TY - JOUR

T1 - Vacuum fluctuations of a scalar field during inflation

T2 - Quantum versus stochastic analysis

AU - Onemli, V. K.

N1 - Publisher Copyright:
© 2015 American Physical Society.

PY - 2015/5/29

Y1 - 2015/5/29

N2 - We consider an infrared truncated massless minimally coupled scalar field with a quartic self-interaction in the locally de Sitter background of an inflating universe. We compute the two-point correlation function of the scalar at one- and two-loop order applying quantum field theory. The tree-order correlator at a fixed comoving separation (that is at an increasing physical distance) freezes into a nonzero value. At a fixed physical distance, it grows linearly with the comoving time. The one-loop correlator, which is the dominant quantum correction, implies a negative temporal growth in the correlation function, at this order, at a fixed comoving separation and at a fixed physical distance. We also obtain quantitative results for variance in space and time of one- and two-loop correlators and infer that the contrast between the vacuum expectation value and the variance becomes less pronounced when the loop corrections are included. Finally, we repeat the analysis of the model applying a stochastic field theory and reach the same conclusions.

AB - We consider an infrared truncated massless minimally coupled scalar field with a quartic self-interaction in the locally de Sitter background of an inflating universe. We compute the two-point correlation function of the scalar at one- and two-loop order applying quantum field theory. The tree-order correlator at a fixed comoving separation (that is at an increasing physical distance) freezes into a nonzero value. At a fixed physical distance, it grows linearly with the comoving time. The one-loop correlator, which is the dominant quantum correction, implies a negative temporal growth in the correlation function, at this order, at a fixed comoving separation and at a fixed physical distance. We also obtain quantitative results for variance in space and time of one- and two-loop correlators and infer that the contrast between the vacuum expectation value and the variance becomes less pronounced when the loop corrections are included. Finally, we repeat the analysis of the model applying a stochastic field theory and reach the same conclusions.

UR - http://www.scopus.com/inward/record.url?scp=84930958967&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.91.103537

DO - 10.1103/PhysRevD.91.103537

M3 - Article

AN - SCOPUS:84930958967

SN - 1550-7998

VL - 91

JO - Physical Review D - Particles, Fields, Gravitation and Cosmology

JF - Physical Review D - Particles, Fields, Gravitation and Cosmology

IS - 10

M1 - 103537

ER -