Spacetime Average Density (SAD) cosmological measures

Page, Don N.

doi:10.1088/1475-7516/2014/11/038

Cited by 5 publications

(6 citation statements)

References 110 publications

(209 reference statements)

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“…These objections are based on the statement that distributions of initial conditions violate a widely accepted naturalness assumption that all forms of inflaton energy (kinetic, gradient, and potential) should initially have the same Planckian scale magnitude [19][20][21]. Three known sources of these distributions-pure no-boundary [1,2] and "tunneling" [3] quantum states of the universe and the Fokker-Planck equation for coarse-grained cosmological evolution [22][23][24][25]-in their turn suffer from intrinsic difficulties associated with a missing clear canonical quantization ground, insufficient amount of generated inflation, anthropic (observer dependence) problems [26][27][28], the rather contrived multiverse measure problem [29], etc.…”

Section: Introductionmentioning

confidence: 99%

Origin of inflation in CFT driven cosmology: $$R^2$$ R 2 -gravity and non-minimally coupled inflaton models

Barvinsky¹,

Kamenshchik²,

Nesterov³

2015

Eur. Phys. J. C

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We present a detailed derivation of the recently suggested new type of hill-top inflation [arXiv:1509.07270] originating from the microcanonical density matrix initial conditions in cosmology driven by conformal field theory (CFT). The cosmological instantons of topology S 1 × S 3 , which set up these initial conditions, have the shape of a garland with multiple periodic oscillations of the scale factor of the spatial S 3 -section. They describe underbarrier oscillations of the inflaton and scale factor in the vicinity of the inflaton potential maximum, which gives a sufficient amount of inflation required by the known CMB data. We build the approximation of two coupled harmonic oscillators for these garland instantons and show that they can generate inflation consistent with the parameters of the CMB primordial power spectrum in the non-minimal Higgs inflation model and in R 2 gravity. In particular, the instanton solutions provide smallness of inflationary slow-roll parameters and η < 0 and their relation ∼ η 2 characteristic of these two models. We present the mechanism of formation of hill-like inflaton potentials, which is based on logarithmic loop corrections to the asymptotically shift-invariant tree-level potentials of these models in the Einstein frame. We also discuss the role of R 2 -gravity as an indispensable finite renormalization tool in the CFT driven cosmology, which guarantees the nondynamical (ghost free) nature of its scale factor and special properties of its cosmological garland-type instantons. Finally, as a solution to the problem of hierarchy between the Planckian scale and the inflation scale we discuss the concept of a hidden sector of conformal higher spin fields. a

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Section: Introductionmentioning

confidence: 99%

Origin of inflation in CFT driven cosmology: $$R^2$$ R 2 -gravity and non-minimally coupled inflaton models

Barvinsky¹,

Kamenshchik²,

Nesterov³

2015

Eur. Phys. J. C

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“…This is admittedly ad hoc, so a more elegant formulation should be found (see e.g. [20]), but at least Agnesi weighting combined with…”

Section: Weighting For the Integral Over Each Spacetimementioning

confidence: 99%

Possibilities for probabilities

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2022

J. Cosmol. Astropart. Phys.

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In ordinary situations involving a small part of the universe, Born's rule seems to work well for calculating probabilities of observations in quantum theory. However, there are a number of reasons for believing that it is not adequate for many cosmological purposes. Here a number of possible generalizations of Born's rule are discussed, explaining why they are consistent with the present statistical support for Born's rule in ordinary situations but can help solve various cosmological problems.

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“…The measure problem of cosmology (see, e.g., [1,2,3,4]) is how to obtain probabilities of observations from the quantum state of the universe. This is particularly a problem when eternal inflation leads to a universe of unbounded size so that there are apparently infinitely many realizations or occurrences of observations of each of many different kinds or types, making the ratios ambiguous.…”

Section: The Measure Problem Of Cosmologymentioning

confidence: 99%

“…This year I have also proposed new measures depending on the Spacetime Average Density (SAD) of observation occurrences within a proper time t from a big bang or bounce [4]. When these measures are combined with…”

Section: Volume Weighting Versus Volume Averagingmentioning

confidence: 99%