Measures on Transitions for Cosmology from Eternal Inflation

Aguirre, Anthony; Gratton, S.; Johnson, Matthew C.

doi:10.1103/physrevlett.98.131301

Cited by 32 publications

(36 citation statements)

References 20 publications

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“…Since an eternally inflating multiverse contains an infinite number of each type of vacuum allowed in the landscape, it is necessary to use some regularization procedure to compute the prior probability distribution. Many such regularization procedures, or probability measures, have been proposed [21,22,23,24,25]. For a more complete and up to date account see Ref.…”

Section: Introductionmentioning

confidence: 99%

Anthropic prediction for a large toy landscape

Olum

Schwartz-Perlov

2007

J. Cosmol. Astropart. Phys.

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The successful anthropic prediction of the cosmological constant depends crucially on the assumption of a flat prior distribution. However, previous calculations in simplified landscape models showed that the prior distribution is staggered, suggesting a conflict with anthropic predictions. Here we analytically calculate the full distribution, including the prior and anthropic selection effects, in a toy landscape model with a realistic number of vacua, N ∼ 10 500 . We show that it is possible for the fractal prior distribution we find to behave as an effectively flat distribution in a wide class of landscapes, depending on the regime of parameter space. Whether or not this possibility is realized depends on presently unknown details of the landscape.

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Section: Introductionmentioning

confidence: 99%

Anthropic prediction for a large toy landscape

Olum

Schwartz-Perlov

2007

J. Cosmol. Astropart. Phys.

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“…On the other hand, we observe Q to lie comfortably in the middle of the anthropic range [45], indicating that no such strong selection effect is at work. 5 Note that a similar story applies to the magnitude of the gravitational constant G [35].…”

Section: A Global Time Cutoffsmentioning

confidence: 95%

Predicting the cosmological constant with the scale-factor cutoff measure

et al. 2008

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It is well known that anthropic selection from a landscape with a flat prior distribution of cosmological constant Λ gives a reasonable fit to observation. However, a realistic model of the multiverse has a physical volume that diverges with time, and the predicted distribution of Λ depends on how the spacetime volume is regulated. We study a simple model of the multiverse with probabilities regulated by a scale-factor cutoff, and calculate the resulting distribution, considering both positive and negative values of Λ. The results are in good agreement with observation. In particular, the scalefactor cutoff strongly suppresses the probability for values of Λ that are more than about ten times the observed value. We also discuss several qualitative features of the scale-factor cutoff, including aspects of the distributions of the curvature parameter Ω and the primordial density contrast Q.

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“…Instead, the particle will orbit the HM point until the trajectory becomes singular due to the evolution of the scale factor. Therefore, we conclude that the instanton must lie along a line of symmetry (passing through the HM point), where the angular momentum can remain zero, and the problem becomes effectively one-dimensional 10 . Slicing the potential along one of the discrete lines of symmetry, we can determine the condition for the existence of a single-pass CDL instanton as…”

Section: Single and Multiple Pass Instantonsmentioning

confidence: 99%

“…In general, τ is not altered much between minima on adjacent sheets of the potential (see Table I). Given a particular value of z, the potential on the τ −plane has a global minimum as 10 It makes little sense to interpret instantons in directions associated with a continuous symmetry as tunneling solutions since there will be a classically allowed path between the instanton endpoints. Discrete lines of symmetry associate d with positive eigenvalues of the mass matrix should be ignored as well.…”

Section: A Euclidean Pathsmentioning

confidence: 99%

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Field dynamics and tunneling in a flux landscape

Johnson

Larfors

2008

Phys. Rev. D

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We investigate field dynamics and tunneling between metastable minima in a landscape of Type IIB flux compactifications, utilizing monodromies of the complex structure moduli space to continuously connect flux vacua. After describing the generic features of a flux-induced potential for the complex structure and Type IIB axio-dilaton, we specialize to the Mirror Quintic Calabi-Yau to obtain an example landscape. Studying the cosmological dynamics of the complex structure moduli, we find that the potential generically does not support slow-roll inflation and that in general the landscape separates neatly into basins of attraction of the various minima. We then discuss tunneling, with the inclusion of gravitational effects, in many-dimensional field spaces. A set of constraints on the form of the Euclidean paths through field space are presented, and then applied to construct approximate instantons mediating the transition between de Sitter vacua in the flux landscape. We find that these instantons are generically thick-wall and that the tunneling rate is suppressed in the large-volume limit. We also consider examples where supersymmetry is not broken by fluxes, in which case near-BPS thin-wall bubbles can be constructed. We calculate the bubble wall tension, finding that it scales like a D-or NS-brane bubble, and comment on the implications of this correspondence. Finally, we present a brief discussion of eternal inflation in the flux-landscape.

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Measures on Transitions for Cosmology from Eternal Inflation

Cited by 32 publications

References 20 publications

Anthropic prediction for a large toy landscape

Anthropic prediction for a large toy landscape

Predicting the cosmological constant with the scale-factor cutoff measure

Field dynamics and tunneling in a flux landscape

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