Energy density of relic gravity waves from inflation

Journal Article · Sun Jul 15 00:00:00 EDT 1990 · Physical Review, D (Particles Fields); (USA)

DOI:https://doi.org/10.1103/PhysRevD.42.453· OSTI ID:7059433

Sahni, V ^[1]

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1. Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario (Canada)

We evaluate both the spectral energy density and the total energy density for relic gravity waves produced during the transition from an early inflationary phase to a matter-dominated Friedmann-Robertson-Walker-type expansion: {ital a}{similar to}{ital t}{sup {ital c}} ({ital c}{lt}1). We find that for power-law inflation the spectral energy density for gravity waves has more power on larger scales than for purely exponential inflation. Evaluating the energy density of created massless particles (both gravitons and massless scalars) we find that in the case of exponential inflation the ratio of the density of created particles to the total density of matter is a constant, if {ital c}{ge}1/2. This unusual behavior is a consequence of the fact that the equation of state for created particles mimics the equation of state for matter driving the expansion of the Universe. As a result, self-consistent solutions of the Einstein equations can be found, in which the expansion of the Universe is sustained solely by the ongoing production of massless particles, so that {ital G}{sub {mu}{nu}}=8{pi}{ital G}{l angle}{ital T}{sub {mu}{nu}}{r angle}. In the case of power-law and quasiexponential inflation we find that the ratio of the energy density of gravity waves to the background matter density increases with time, as gravity waves with longer wavelengths and larger amplitudes enter the horizon at successively later epochs. This could lead to the energy density of gravity waves becoming comparable to the energy density of matter at late times, if inflation commenced at Planckian energies.

• OSTI ID: 7059433
• Journal Information: Physical Review, D (Particles Fields); (USA), Vol. 42:2; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
GRAVITATIONAL WAVES
ENERGY DENSITY
INFLATIONARY UNIVERSE
EINSTEIN FIELD EQUATIONS
EQUATIONS OF STATE
GRAVITONS
HUBBLE EFFECT
KLEIN-GORDON EQUATION
MASSLESS PARTICLES
PARTICLE PRODUCTION
SCALAR FIELDS
SPACE-TIME
SPECTRAL DENSITY
VACUUM STATES
COSMOLOGICAL MODELS
DIFFERENTIAL EQUATIONS
ELEMENTARY PARTICLES
EQUATIONS
FIELD EQUATIONS
FUNCTIONS
GRAVITATIONAL RADIATION
MATHEMATICAL MODELS
PARTIAL DIFFERENTIAL EQUATIONS
POSTULATED PARTICLES
RADIATIONS
SPECTRAL FUNCTIONS
WAVE EQUATIONS
640106* - Astrophysics & Cosmology- Cosmology