http://arxiv.org/abs/1311.1590
In the context of the teleparallel equivalent of general relativity, we apply a definition for an energy-momentum tensor that naturally arises in this framework. Specially, that quantity leads to a simple definition of pressure that includes the pressure of matter, the “vacuum pressure” (due to a cosmological constant) and, moreover, the pressure of the \textit{gravitational} field itself. We computed that total pressure on the cosmological apparent horizon of a Friedmann-Robertson-Walker universe. In particular, we considered a spatially flat universe. In this case, by resorting to the current observational data on the cosmological observables we have found that pressure is negative and the corresponding energy density associated to it is so close to the actual \textit{critical density} of the universe.
Fri, 8 Nov 13
11/58
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