Dynamical Selection of the Cosmological `Constant' in the Cyclic Model

نویسندگان

  • Jason Pollack
  • Paul Steinhardt
چکیده

The cyclic model resolves the homogeneity and atness problems of big bang cosmology via a period of ultra-slow contraction rather than the accelerated expansion found in in ationary schemes. Patches of space in the four-dimensional e ective theory undergo repeated big bangs, thus allowing the introduction of timescales far greater than the 14 billion years since the last one. The conditions imposed by the requirement of continued cycling allow the possibility of dynamical selection, as opposed to the anthropic selection commonly used in in ation, in which the cycling conditions act as a sieve which repeatedly eliminates extreme parameter values without reference to the presence of observers. In this paper we examine the various constraints set on the cosmological constant within the context of a cyclic model, then combine this with the concept of a dynamical relaxation mechanism for the cosmological `constant' to propose a natural, non-anthropic explanation for its present value.

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تاریخ انتشار 2011