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spring workshop on gravity and cosmology

16–17 May 2019
University of Warsaw
Europe/Zurich timezone

Contribution List

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3. Merger rate of primordial black hole binaries:I
須山輝明 Suyama
16/05/2019, 09:30

Discovery of black hole binaries by LIGO/Virgo provoked a renewed interest in primordial black holes (PBHs). After I give a brief introduction of PBHs, I explain how PBHs form binaries and compute their merger rate.
4. Merger rate of primordial black hole binaries:II
須山輝明 Suyama
16/05/2019, 11:00

This is a continuation of my first talk.
5. Early Universe Models in Light of the Swampland Constraints
Prof. Robert Brandenberger (McGill University)
16/05/2019, 12:15

Cosmological inflation has been the main paradigm for early universe cosmology since the early 1980s, but we are still lacking an embedding of inflation into fundamental physics. I will discuss constraints on inflation, and on other scenarios of early universe cosmology, which arise when one tries to embed the scenarios into superstring theory.
6. Stochastic inflation beyond slow roll
David Wands (ICG)
16/05/2019, 14:30

I will discuss how to apply stochastic formalism for inflation beyond the usual slow-roll approximation. We verify that the assumptions on which the stochastic formalism relies still hold even far from the slow-roll attractor. In particular this requires the separate universe assumption to hold for long-wavelength perturbations of the scalar field beyond slow roll. In general, there is a gauge...
7. Stochastic Inflation and Primordial Black Holes
Vincent Vennin (APC Paris)
16/05/2019, 15:15

Primordial black holes can be seeded by large cosmological fluctuations produced during inflation. This happens if the potential for inflation is sufficiently flat in some regions. However, in such regions, the dynamics of the inflaton is dominated by quantum diffusion rather than by classical slow roll. This implies that the standard method to calculate the amplitude of the fluctuations,...
9. Testing PBHs by gravitational-wave observations
須山輝明 Suyama
16/05/2019, 16:30

Given a possibility that black holes detected by LIGO/Virgo are PBHs, a next direction we should proceed is to propose ideas for testing the PBH hypothesis. I will introduce my recent proposal that makes use of the mass distribution as well as other proposals.
11. free discussion
16/05/2019, 17:15
12. Numerical simulation of Primordial Black Holes
Albert Escrivà
17/05/2019, 09:00

In this talk I will present a fast and new procedure to calculate the averaged mass excess threshold δc of primordial black holes from a given cosmological perturbation profile using pseudo-spectral methods, numerically solving the Misner-Sharp equations. I apply the method in the cosmological context to put constraints on the inflationary power spectrum.
10. Primordial Black Holes abundance
Cristiano Germani
17/05/2019, 09:30

In this talk I will discuss how to calculate the abundance of primordial black holes given an inflationary power spectrum
13. Failure of the stochastic approach to inflation beyond slow-roll
Diego Cruces (ICC. UB)
17/05/2019, 10:45

After giving a pedagogical review I will clarify that the stochastic approach to inflation is generically reliable only at zeroth order in the (geometrical) slow-roll parameter ϵ_1 if and only if ϵ2_2≪6/ϵ_1, with the notable exception of slow-roll. This is due to the failure of the stochastic ΔN formalism in its standard formulation. However, by keeping the formalism in its regime of validity,...
8. Inflationary correlators from the stochastic spectral expansion
Mr Tommi Markkanen
17/05/2019, 11:15

Continuing on the topic of the stochastic formalism, in this talk I will present the lesser known stochastic spectral expansion and show how it can be used to calculate correlation functions generated during inflation. I also discuss the shortcomings of some of the commonly used approximations and present the full stochastic calculation for the isocurvature spectrum of a decoupled spectator,...
14. free discussion
17/05/2019, 12:00
15. Properties of the primordial power spectrum for PBH production
Ioannis Dalianis ( NTU Athens)
17/05/2019, 14:00

I will discuss the properties of the primordial power spectrum so that PBHs are produced in accordance with the constraints coming from the CMB and BBN observables. I will mainly focus on the large wavenumbers of the power spectrum where, if there is a peak, PBH with sub-solar masses are generated. Then I will describe the scenario that the dark matter in the universe is comprised either of...
16. Oscillations that mimick weak lensing
Guillem Domenech (uni. heidelberg)
17/05/2019, 15:15

The latest Planck’s analysis of the power spectrum finds 10% more lensing smoothing than predicted by LCDM at 2 sigma. If it is not a statistical fluke, it could indicate new physics that mimick the smoothing effect of lensing. What could that be and how was generated? First, I will show you that oscillations in the primordial power spectrum with the same frequency as the acoustic peaks but...
17. free discussion
17/05/2019, 16:00
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