Is cosmology compatible with blue gravity waves?

Journal Article · Thu May 15 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.101301· OSTI ID:21210172

Camerini, Roberta; Durrer, Ruth; Melchiorri, Alessandro; Riotto, Antonio ^[1]

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1. Physics Department, Universita di Roma 'La Sapienza', Ple Aldo Moro 2, 00185, Rome (Italy)

A primordial gravitational wave background with positive (blue) spectral index is expected in several nonstandard inflationary cosmologies where the stress-energy tensor violates the null energy condition. Here we show that a sizable amount of blue gravitational waves is compatible with current cosmological and astrophysical data. So far most of the works on parameter estimation from cosmic microwave background data have assumed a negative or negligible spectral index. The present limits on cosmological parameters, especially on the scalar spectral index, widen up considerably when one allows also for blue tilts of the tensor spectrum. Since the amplitude of the cosmic microwave background (CMB) B-mode polarization is larger in these models, future data from Planck are likely to provide crucial measurements.

• OSTI ID: 21210172
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 10 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASTROPHYSICS
COSMOLOGY
GRAVITATIONAL WAVES
GRAVITY WAVES
MICROWAVE RADIATION
POLARIZATION
RELICT RADIATION