Limitations of anthropic predictions for the cosmological constant $Λ$: Cosmic Heat Death of Anthropic Observers
| dc.creator | Mersini-Houghton, L. | |
| dc.creator | Adams, F. | |
| dc.date | 2008-10-27 | |
| dc.date.accessioned | 2026-07-07T12:32:24Z | |
| dc.date.available | 2026-07-07T12:32:24Z | |
| dc.description | This paper investigates anthropic bounds on the vacuum energy $Λ$. We first consider the possibility of cosmic observers existing at any random time (including the future) for constant $Λ$, and take into account the suppression of new structure formation as the universe approaches its eternal DeSitter (DS) geometry. Structures that collapse prior to the era of $Λ$-domination will lose causal contact with our Hubble volume within a finite (short) conformal time $τ_{\ast}$. Any remnants within our Hubble volume then suffer a cosmological heat death after the universe becomes DS. The probability for finding observers by random measurements in the volume bound by the DeSitter horizon is $P \simeq 0$, and it is a simple consequence of the information loss problem for eternal DS spaces resulting from the finite and constant value of its temperature $T_{DS} \simeq Λ^{-1/2}$ and entropy $S = 3/(GΛ)$. By contrast, for geometries with $Λ= 0$, structures can condense and entropy production can continue without bounds at any epoch. The probability of finding observers in $Λ= 0$ geometries is thus overwhelming higher than in DS spaces. As a result, anthropic reasoning does not explain the small but nonzero vacuum energy observed in our universe. We also address the case where observers are considered only at a specially chosen time -- like the present epoch -- but relax the allowed values of starting density fluctuations and hence the redshift of galaxy formation. In this latter case, the bounds on a $Λ$ can be millions of times larger than previous estimates -- and the observed value. We thus conclude that anthropic reasoning has limited predictive power. | |
| dc.description | 7pgs, published | |
| dc.identifier | https://arxiv.org/abs/0810.4914 | |
| dc.identifier | http://arxiv.org/abs/0810.4914 | |
| dc.identifier | Class.Quant.Grav.25:165002,2008 | |
| dc.identifier | doi:10.1088/0264-9381/25/16/165002 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/216770 | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.subject | Astrophysics | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.subject | High Energy Physics - Theory | |
| dc.title | Limitations of anthropic predictions for the cosmological constant $Λ$: Cosmic Heat Death of Anthropic Observers | |
| dc.type | text |