TY - JOUR
T1 - Dark energy and the return of the phoenix universe
AU - Lehners, Jean Luc
AU - Steinhardt, Paul J.
N1 - Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2009/3/2
Y1 - 2009/3/2
N2 - In cyclic universe models based on a single scalar field (e.g., the radion determining the distance between branes in M theory), virtually the entire Universe makes it through the ekpyrotic smoothing and flattening phase, bounces, and enters a new epoch of expansion and cooling. This stable evolution cannot occur, however, if scale-invariant curvature perturbations are produced by the entropic mechanism because it requires two scalar fields (e.g., the radion and the Calabi-Yau dilaton) evolving along an unstable classical trajectory. In fact, we show here that an overwhelming fraction of the Universe fails to make it through the ekpyrotic phase; nevertheless, a sufficient volume survives and cycling continues forever provided the dark energy phase of the cycle lasts long enough, of order a trillion years. Two consequences are a new role for dark energy and a global structure of the Universe radically different from that of eternal inflation.
AB - In cyclic universe models based on a single scalar field (e.g., the radion determining the distance between branes in M theory), virtually the entire Universe makes it through the ekpyrotic smoothing and flattening phase, bounces, and enters a new epoch of expansion and cooling. This stable evolution cannot occur, however, if scale-invariant curvature perturbations are produced by the entropic mechanism because it requires two scalar fields (e.g., the radion and the Calabi-Yau dilaton) evolving along an unstable classical trajectory. In fact, we show here that an overwhelming fraction of the Universe fails to make it through the ekpyrotic phase; nevertheless, a sufficient volume survives and cycling continues forever provided the dark energy phase of the cycle lasts long enough, of order a trillion years. Two consequences are a new role for dark energy and a global structure of the Universe radically different from that of eternal inflation.
UR - http://www.scopus.com/inward/record.url?scp=63149142157&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=63149142157&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.79.063503
DO - 10.1103/PhysRevD.79.063503
M3 - Article
AN - SCOPUS:63149142157
SN - 1550-7998
VL - 79
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
IS - 6
M1 - 063503
ER -