FENS Seminar: Cosmological Evolution of Vacuum and Cosmic acceleration

Physics Seminar, 5 Jan 2011, Wednesday, 13:40, FENS L045




Dr. Ali Kaya


Boğaziçi Üniversitesi



Title: Cosmological evolution of vacuum and cosmic acceleration



Abstract: We study the
cosmological impact of a free massless quantum scalar field in a
Friedmann-Robertson-Walker space-time. Assuming that the scalar is
placed in


its ground state, a simple expression for the stress-energy-momentum tensor is


obtained using adiabatic regularization. We show that vacuum energy density


grows from zero up to the fourth power of the Hubble parameter in about one


Hubble time, vacuum fluctuations give positive acceleration and they can


completely alter the cosmic evolution of the universe dominated otherwise by


cosmological constant, radiation or pressureless dust.