Is the Hypothesis About a Low Entropy Initial State of the Universe Necessary for Explaining the Arrow of Time

According to statistical mechanics, micro-states of an isolated physical system (say, a gas in a box) at time t0 in a given macro-state of less-than-maximal entropy typically evolve in such a way that the entropy at time t increases with jt t0j in both time directions. In order to account for the observed entropy increase in only one time direction, the thermodynamic arrow of time, one usually appeals to the hypothesis that the initial state of the universe was one of very low entropy. In certain recent models of cosmology, however, no hypothesis about the initial state of the universe is invoked. We discuss how the emergence of a thermodynamic arrow of time in such models can nevertheless be compatible with the above-mentioned consequence of statistical mechanics, appearances to the contrary notwithstanding.

• Publication year

  2016

• Venue

  Physical Review D

• Publication date

  2016-02-08

• Fields of study

  Physics

• Identifiers
  DOI 10.1103/PhysRevD.94.023520arXiv 1602.05601
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• No claims are published for this paper.

• No concepts are published for this paper.

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