TY - JOUR
T1 - A measure of de Sitter entropy and eternal inflation
AU - Arkani-Hamed, Nima
AU - Dubovsky, Sergei
AU - Nicolis, Alberto
AU - Trincherini, Enrico
AU - Villadoro, Giovanni
PY - 2007/5/1
Y1 - 2007/5/1
N2 - We show that in any model of non-eternal inflation satisfying the null energy condition, the area of the de Sitter horizon increases by at least one Planck unit in each inflationary e-folding. This observation gives an operational meaning to the finiteness of the entropy SdS of an inflationary de Sitter space eventually exiting into an asymptotically flat region: the asymptotic observer is never able to measure more than e SdS independent inflationary modes. This suggests a limitation on the amount of de Sitter space outside the horizon that can be consistently described at the semiclassical level, fitting well with other examples of the breakdown of locality in quantum gravity, such as in black hole evaporation. The bound does not hold in models of inflation that violate the null energy condition, such as ghost inflation. This strengthens the case for the thermodynamical interpretation of the bound as conventional black hole thermodynamics also fails in these models, strongly suggesting that these theories are incompatible with basic gravitational principles.
AB - We show that in any model of non-eternal inflation satisfying the null energy condition, the area of the de Sitter horizon increases by at least one Planck unit in each inflationary e-folding. This observation gives an operational meaning to the finiteness of the entropy SdS of an inflationary de Sitter space eventually exiting into an asymptotically flat region: the asymptotic observer is never able to measure more than e SdS independent inflationary modes. This suggests a limitation on the amount of de Sitter space outside the horizon that can be consistently described at the semiclassical level, fitting well with other examples of the breakdown of locality in quantum gravity, such as in black hole evaporation. The bound does not hold in models of inflation that violate the null energy condition, such as ghost inflation. This strengthens the case for the thermodynamical interpretation of the bound as conventional black hole thermodynamics also fails in these models, strongly suggesting that these theories are incompatible with basic gravitational principles.
KW - Black holes
KW - Cosmology of theories beyond the SM
KW - dS vacua in string theory
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U2 - 10.1088/1126-6708/2007/05/055
DO - 10.1088/1126-6708/2007/05/055
M3 - Article
AN - SCOPUS:34547565805
SN - 1126-6708
VL - 2007
JO - Journal of High Energy Physics
JF - Journal of High Energy Physics
IS - 5
M1 - 055
ER -