704 research outputs found
The Nature and Origin of Time-asymmetric Spacetime Structures
Time-asymmetric spacetime structures, in particular those representing black
holes and the expansion of the universe, are intimately related to other arrows
of time, such as the second law and the retardation of radiation. The nature of
the quantum arrow, often attributed to a collapse of the wave function, is
essential, in particular, for understanding the much discussed "black hole
information loss paradox". However, this paradox assumes a new form and can
possibly be avoided in a consistent causal treatment that may be able to avoid
horizons and singularities. - A "master arrow", which combines all arrows of
time, does not have to be identified with a direction of the formal time
parameter that serves to formulate the dynamics as a succession of global
states (a trajectory in configuration or Hilbert space). It may even change
direction with respect to a fundamental physical clock such as the cosmic
expansion parameter if this was formally extended either into a future
contraction era or to negative "pre-big-bang" values.Comment: V2: Causal arguments regarding the information loss paradox are
emphasized (Sect. 3); V3-V11: Comments and references added; V5: published;
V6: "Note after publication" added; V11: 24 pages pdf, 3 figure
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