scholarly journals Constant-rate inflation: primordial black holes from conformal weight transitions

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Kin-Wang Ng ◽  
Yi-Peng Wu
Keyword(s):  
Black Holes ◽  
Power Spectrum ◽  
Analytic Solutions ◽  
Conformal Weight ◽  
Late Time ◽  
Primordial Black Holes ◽  
De Sitter ◽  
Slow Roll ◽  
Time Scaling ◽  
Constant Rate

Abstract Constant-rate inflation, including ultra-slow-roll inflation as a special case, has been widely applied to the formation of primordial black holes with a significant deviation from the standard slow-roll conditions at both the growing and decaying phases of the power spectrum. We derive analytic solutions for the curvature perturbations with respect to the late-time scaling dimensions (conformal weights) constrained by the dilatation symmetry of the de Sitter background and show that the continuity of conformal weights across different rolling phases is protected by the adiabatic condition of the inflaton perturbation. The temporal excitation of subleading states (with the next-to-lowest conformal weights), recorded as the “steepest growth” of the power spectrum, is triggered by the entropy production in the transition from the slow-roll to the constant-rate phases.

PRIMORDIAL BLACK HOLE PAIR CREATION IN R2 THEORY

1998 ◽  
Vol 13 (28) ◽  
pp. 2289-2293 ◽  
Author(s):  
B. C. PAUL ◽  
S. MUKHERJEE ◽  
G. P. SINGH ◽  
A. BEESHAM
Keyword(s):  
Black Holes ◽  
Semiclassical Approximation ◽  
Pair Creation ◽  
Quadratic Term ◽  
Inflationary Universe ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
De Sitter ◽  
Gravitational Action ◽  
Spatial Section

The probability for quantum creation of an inflationary universe with a pair of black holes has been studied in semiclassical approximation with Hartle–Hawking boundary conditions, assuming a gravitational action which includes a quadratic term in the scalar curvature αR2, α being a constant. The action of the instanton responsible for creating such a universe, with a spatial section with S1×S2 topology, is seen to be less than that of a de Sitter S3 instanton, unless α<-1/(8Λ), where Λ is the cosmological constant. Since negative α implies a classical instability, the probability for production of primordial black holes seems to be suppressd in R2-theory.

On Primordial Black Holes and secondary gravitational waves generated from inflation with solo/multi-bumpy potential

2021 ◽  
Author(s):  
Rui feng Zheng ◽  
Jia ming Shi ◽  
Taotao Qiu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Waves ◽  
Power Spectra ◽  
Small Scale ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
Slow Roll ◽  
Spherical Collapse ◽  
Scalar Perturbations

Abstract It is well known that primordial black hole (PBH) can be generated in inflation process of the early universe, especially when the inflaton field has some non-trivial features that could break the slow-roll condition. In this paper, we investigate a toy model of inflation with bumpy potential, which has one or several bumps. We found that potential with multi-bump can give rise to power spectra with multi peaks in small-scale region, which can in turn predict the generation of primordial black holes in various mass ranges. We also consider the two possibilities of PBH formation by spherical collapse and elliptical collapse. And discusses the scalar-induced gravitational waves (SIGWs) generated by the second-order scalar perturbations.

scholarly journals Steepest growth of the power spectrum and primordial black holes

2019 ◽  
Vol 2019 (06) ◽  
pp. 028-028 ◽  
Author(s):  
Christian T. Byrnes ◽  
Philippa S. Cole ◽  
Subodh P. Patil
Keyword(s):  
Black Holes ◽  
Power Spectrum ◽  
Primordial Black Holes

scholarly journals EVOLUTION OF PRIMORDIAL BLACK HOLE MASS SPECTRUM IN BRANS–DICKE THEORY

2013 ◽  
Vol 22 (05) ◽  
pp. 1350022 ◽  
Author(s):  
D. DWIVEDEE ◽  
B. NAYAK ◽  
L. P. SINGH
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Spectrum ◽  
Energy Density ◽  
Analytic Solutions ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
Black Hole Mass ◽  
Linear And Nonlinear ◽  
The Universe

We investigate the evolution of primordial black hole mass spectrum by including both accretion of radiation and Hawking evaporation within Brans–Dicke (BD) cosmology in radiation-, matter- and vacuum-dominated eras. We also consider the effect of evaporation of primordial black holes on the expansion dynamics of the universe. The analytic solutions describing the energy density of the black holes in equilibrium with radiation are presented. We demonstrate that these solutions act as attractors for the system ensuring stability for both linear and nonlinear situations. We show, however, that inclusion of accretion of radiation delays the onset of this equilibrium in all radiation-, matter- and vacuum-dominated eras.

scholarly journals Large power spectrum and primordial black holes in the effective theory of inflation

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Guillermo Ballesteros ◽  
Sebastián Céspedes ◽  
Luca Santoni
Keyword(s):  
Power Spectrum ◽  
Energy Scale ◽  
Effective Theory ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
De Sitter ◽  
Effective Coupling ◽  
Large Power ◽  
Single Field ◽  
Large Quantum

Abstract We study the generation of a large power spectrum, necessary for primordial black hole formation, within the effective theory of single-field inflation. The mechanisms we consider include a transition into a ghost-inflation-like phase and scenarios where an exponentially growing mode is temporarily turned on. In the cases we discuss, the enhancement in the power spectrum results from either a swift change in some effective coupling or a modification of the dispersion relation for the perturbations, while the background evolution remains unchanged and approximately de Sitter throughout inflation. The robustness of the results is guaranteed thanks to a weakly broken galileon symmetry, which protects the effective couplings against large quantum corrections. We discuss how the enhancement of the power spectrum is related to the energy scale of the operators with weakly broken galileon invariance, and study the limits imposed by strong coupling and the validity of the perturbative expansion.

Inflationary dynamics in f(𝒢) gravity

2017 ◽  
Vol 26 (04) ◽  
pp. 1750030 ◽  
Author(s):  
M. Sharif ◽  
Ayesha Ikram
Keyword(s):  
Scalar Field ◽  
Equation Of State ◽  
Power Spectrum ◽  
Universe Model ◽  
De Sitter ◽  
Slow Roll ◽  
Homogeneous Universe ◽  
Text Model ◽  
Flow Functions ◽  
Hubble Flow

This paper investigates inflationary dynamics for isotropic and homogeneous universe model in the background of [Formula: see text] gravity. We construct Hubble-flow functions, slow-roll parameters, amplitude of scalar power spectrum, spectral index and tensor–scalar ratio for a particular form of equation of state which describes quasi-de Sitter expansion. The dynamics of inflationary epoch is analyzed for scalar field as well as fluid cosmology with viable power-law [Formula: see text] model. We obtain different potential functions that correspond to chaotic inflation and Starobinsky type models. The graphical behavior of these parameters shows compatible results with observational Planck 2015 data in this gravity.

scholarly journals Constraints on the primordial curvature power spectrum from primordial black holes

2019 ◽  
Vol 100 (6) ◽  
Author(s):  
Gabriela Sato-Polito ◽  
Ely D. Kovetz ◽  
Marc Kamionkowski
Keyword(s):  
Black Holes ◽  
Power Spectrum ◽  
Primordial Black Holes

scholarly journals Topological or rotational non-Abelian gauge fields from Einstein-Skyrme holography

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Casey Cartwright ◽  
Benjamin Harms ◽  
Matthias Kaminski
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Analytic Solutions ◽  
Charge Density Waves ◽  
Entropy Density ◽  
Hawking Temperature ◽  
De Sitter ◽  
Abelian Gauge ◽  
Qcd Phase Diagram ◽  
Chern Numbers

Abstract We report analytically known states at non-zero temperature which may serve as a powerful tool to reveal common topological and thermodynamic properties of systems ranging from the QCD phase diagram to topological phase transitions in condensed matter materials. In the holographically dual gravity theory, these are analytic solutions to a five-dimensional non-linear-sigma (Skyrme) model dynamically coupled to Einstein gravity. This theory is shown to be holographically dual to $$ \mathcal{N} $$ N = 4 Super-Yang-Mills theory coupled to an SU(2)-current. All solutions are fully backreacted asymptotically Anti-de Sitter (AdS) black branes or holes. One family of global AdS black hole solutions contains non-Abelian gauge field configurations with positive integer Chern numbers and finite energy density. Larger Chern numbers increase the Hawking-Page transition temperature. In the holographically dual field theory this indicates a significant effect on the deconfinement phase transition. Black holes with one Hawking temperature can have distinct Chern numbers, potentially enabling topological transitions. A second family of analytic solutions, rotating black branes, is also provided. These rotating solutions induce states with propagating charge density waves in the dual field theory. We compute the Hawking temperature, entropy density, angular velocity and free energy for these black holes/branes. These correspond to thermodynamic data in the dual field theory. For these states the energy-momentum tensor, (non-)conserved current, and topological charge are interpreted.

scholarly journals Late-time tails, entropy aspects, and stability of black holes with anisotropic fluids

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
B. Cuadros-Melgar ◽  
R. D. B. Fontana ◽  
Jeferson de Oliveira
Keyword(s):  
Black Holes ◽  
Causal Structure ◽  
Quasinormal Modes ◽  
Black Hole Entropy ◽  
Late Time ◽  
Time Behavior ◽  
Brick Wall ◽  
De Sitter ◽  
Four Dimensions ◽  
Anisotropic Fluids

AbstractIn this work we consider black holes surrounded by anisotropic fluids in four dimensions. We first study the causal structure of these solutions showing some similarities and differences with Reissner–Nordström–de Sitter black holes. In addition, we consider scalar perturbations on this background geometry and compute the corresponding quasinormal modes. Moreover, we discuss the late-time behavior of the perturbations finding an interesting new feature, i.e., the presence of a subdominant power-law tail term. Likewise, we compute the Bekenstein entropy bound and the first semiclassical correction to the black hole entropy using the brick wall method, showing their universality. Finally, we also discuss the thermodynamical stability of the model.

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