Paper: astro-ph/0605173
Date: Sat, 6 May 2006 15:36:30 GMT (49kb)

Title: Why the cosmological constant is small and positive

Authors: Paul J. Steinhardt and Neil Turok

Comments: 15 pages, 1 figure
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Within conventional big bang cosmology, it has proven to be very difficult to
understand why today's cosmological constant is so small. In this paper, we
show that a cyclic model of the universe can naturally incorporate a dynamical
mechanism that automatically relaxes the value of the cosmological constant,
taking account of contributions to the vacuum density at all energy scales.
Because the relaxation time grows exponentially as the vacuum density
decreases, nearly every volume of space spends an overwhelming majority of the
time at the stage when the cosmological constant is small and positive, as
observed today.

\\ ( http://arXiv.org/abs/astro-ph/0605173 , 49kb)