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The generic nature of the global and non-entropic arrow of time and the dual role of the energy–momentum tensor

2004; Institute of Physics; Volume: 37; Issue: 15 Linguagem: Inglês

10.1088/0305-4470/37/15/012

1361-6447

Mario Castagnino, Olímpia Lombardi,

Black Holes and Theoretical Physics

In this paper we adopt a generic, global and non-entropic approach to the problem of the arrow of time, according to which the arrow of time is a generic, intrinsic and geometrical property of spacetime. We demonstrate that the arrow of time so defined is generic in the sense that any spacetime with physically reasonable properties (e.g. time-orientability and global time) will be endowed with an arrow of time. The only exceptions are very special cases belonging to a subset of zero measure of the set of all possible spacetimes. We also show the dual role played by the energy–momentum tensor in the context of our approach. On one hand, the energy–momentum tensor is the intermediate step that permits us to turn the geometrical time-asymmetry of the universe into a local arrow of time manifested as a time-asymmetric energy flow. On the other hand, the energy–momentum tensor supplies the basis for deducing the time-asymmetry of quantum field theory, posed as an axiom in this theory.