Tufts/CfA/MIT Cosmology Seminar, at Tufts:

Tuesday, March 13, 2001
2:30 pm
Robinson Hall, Room 250
Refreshments at 2:00 in Knipp Library, Room 251

"Null Energy Condition Violations in Eternal Inflation"


Serge Winitzki
Case Western Reserve University

Abstract:

The usual scenario of ``eternal inflation'' involves an approximally de Sitter spacetime undergoing upward fluctuations of the local Hubble rate H. This spacetime requires frequent violations the Null Energy Condition (NEC). We investigate the fluctuations of the energy-momentum tensor of the scalar field in de Sitter space as possible source of such violations. We find that fluctuations of the energy-momentum tensor smeared in space and time are well-defined and may provide the NEC violations. Our results for slow-roll inflation are consistent with the standard calculations of inflationary density fluctuations. In the diffusive regime where quantum fluctuations dominate the slow-roll evolution, the magnitude of smeared energy-momentum tensor fluctuations is large enough to create NEC violations.

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