States of low energy in homogeneous and inhomogeneous expanding spacetimes
Abstract
We construct states on the algebra of the Klein-Gordon field that minimize the energy density in homogeneous and in inhomogeneous spacetimes, both with compact Cauchy hypersurfaces. The energy density is measured by geodesic observers and smeared over a spacelike slab of spacetime, entirely containing a Cauchy hypersurface and extended in time. We further show that these states are Hadamard states. The present construction generalizes the construction of states of low energy in Robertson-Walker spacetimes presented by Olbermann (2007 Class. Quantum Grav. 24 5011).
- Publication:
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Classical and Quantum Gravity
- Pub Date:
- December 2013
- DOI:
- 10.1088/0264-9381/30/23/235035
- arXiv:
- arXiv:1302.3174
- Bibcode:
- 2013CQGra..30w5035T
- Keywords:
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- General Relativity and Quantum Cosmology;
- Mathematical Physics
- E-Print:
- Substantial modifications made in the text. This version was accepted for publication in Class. Quant. Grav