Black Holes of a Minimal Size in String Gravity

Alexeyev, S. O.; Sazhin, M. V.; Pomazanov, M. V.

doi:10.1142/s0218271801000780

Cited by 13 publications

(9 citation statements)

References 7 publications

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“…without having an unambigous and complete theory of quantum gravity [10]. Furthermore, some cosmologically relevant wavelengths must, at some early stage, have been trans-Planckian [13,14,15,16]; this can cast doubts on the validity of the cosmological perturbation predictions of inflation. Finally, the usual and simpler models of inflation need a scalar field [17], whose theoretical properties demanded for setting up the inflationary phase are not obviously compatible with those obtained from well-motivated fundamental particle physics theory [18,19] (a new perspective was, however, suggested [20]).…”

Section: Introductionmentioning

confidence: 99%

Cosmology without inflation

2008

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We propose a new cosmological paradigm in which our observed expanding phase is originated from an initially large contracting Universe that subsequently experienced a bounce. This category of models, being geodesically complete, is non-singular and horizon-free, and can be made to prevent any relevant scale to ever have been smaller than the Planck length. In this scenario, one can find new ways to solve the standard cosmological puzzles. One can also obtain scale invariant spectra for both scalar and tensor perturbations: this will be the case, for instance, if the contracting Universe is dust-dominated at the time at which large wavelength perturbations get larger than the curvature scale. We present a particular example based on a dust fluid classically contracting model, where a bounce occurs due to quantum effects, in which these features are explicit.

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Section: Introductionmentioning

confidence: 99%

Cosmology without inflation

2008

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“…It was also found that pbhs are a great probe of the early universe with a varying gravitational constant (Carr 2001). Finally, significant progress has been made in the understanding Send offprint requests to: A. Barrau, e-mail: barrau@isn.in2p3.fr of the evaporation mechanism itself, both at usual energies (Parikh & Wilczek 2000) and in the near-planckian tail of the spectrum (Barrau & Alexeyev 2001;Alexeyev et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Antiprotons from primordial black holes

Barrau

Boudoul

Donato

et al. 2002

A&A

121

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Abstract. Primordial black holes (pbhs) have motivated many studies since it was shown that they should evaporate and produce all kinds of particles (Hawking 1974). Recent experimental measurements of cosmic rays with great accuracy, theoretical investigations on the possible formation mechanisms and detailed evaporation processes have revived the interest in such astrophysical objects. This article aims to use the latest developments in antiproton propagation models Donato et al. 2001) together with new data from BESS, CAPRICE and AMS experiments to constrain the local amount of pbh dark matter. Depending on the diffusion halo parameters and on the details of the emission mechanisms, we derive an average upper limit of the order of ρ PBH ≈ 1.7 × 10 −33 g cm −3 .

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“…It was also found that s are a useful probe of the early Universe with a varying gravitational constant (Carr 2000). Finally, significant progress has been made in the understanding of the evaporation mechanism itself, both at usual energies (Parikh & Wilczek 2000) and in the near-Planckian tail of the spectrum (Barrau & Alexeyev 2001;Alexeyev et al 2001;Alexeyev et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Antideuterons as a probe of primordial black holes

Barrau

Boudoul

Donato

et al. 2003

A&A

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Abstract.In most cosmological models, primordial black holes () should have formed in the early Universe. Their Hawking evaporation into particles could eventually lead to the formation of antideuterium nuclei. This paper is devoted to a first computation of this antideuteron flux. The production of these antinuclei is studied with a simple coalescence scheme, and their propagation in the Galaxy is treated with a well-constrained diffusion model. We compare the resulting primary flux to the secondary background, due to the spallation of protons on the interstellar matter. Antideuterons are shown to be a very sensitive probe for primordial black holes in our Galaxy. The next generation of experiments should allow investigators to significantly improve the current upper limit, nor even provide the first evidence of the existence of evaporating black holes.

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Black Holes of a Minimal Size in String Gravity

Cited by 13 publications

References 7 publications

Cosmology without inflation

Cosmology without inflation

Antiprotons from primordial black holes

Antideuterons as a probe of primordial black holes

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