ICCUB School 2023: Primordial Black Holes

26 Jun 2023, 08:30 → 30 Jun 2023, 18:30 Europe/Madrid

UB Physics Faculty

ICCUB School

Primordial Black Holes (PBHs), arguably the most economical candidates for Dark Matter, have recently fostered an intense debate within the scientific community. As a result of that, in recent years, there has been a better understanding of their formation, abundance, and signatures.

The aim of the school is to bring together latest key developments on PBHs into a pedagogical and coherent picture. The focus of the school is on PBHs generated from rare inflationary perturbations.
Their formation, statistical distribution and signatures are going to be core topics of the school.

This school is intended for PhD students and young postdocs that have general knowledge of cosmological perturbations theory. Nevertheless, we also provide a pre-school lecture on basics concepts of perturbations theory.

Lectures start every morning at 9:30 and finish at 18:00 (with small variations). Finally, there is also a scheduled time for selected talks from the students.

Limited number of places.

Lecturers

• Ana Achucarro (Leiden University, Netherlands)
  
  "Enhancement mechanisms for cosmological perturbations"
   
• Guillem Domènech (Leibniz University, Germany)
  
  “Gravitational waves signatures of primordial black holes”
   
• Albert Escrivà (Nagoya University, Japan)
  
  "Primordial Black Holes formation, theory and simulations"
   
• Natalia Korsakova (APC, France)
  
  “LISA capabilities in the context of PBH physics”
   
• Florian Kuhnel (Ludwig-Maximilians-Universitaet, Germany)
  
  "Constraints on Primordial Black Holes"
   
• Ravi Sheth (University of Pennsylvania, USA)
  
  "The statistics of Primordial Black Holes"

 

Pre-school

• Jaume Garriga (University of Barcelona and ICCUB)
  
  “Basics of cosmological perturbation theory”

 

In addition, there will be a distinguished guest seminar:

Misao Sasaki (Kavli Institute for the Physics and Mathematics of the Universe, Japan)

“PBHs from highly non-Gaussian tails of the probability distribution”

 

When

26th-30th June, 2023 from 9:30Am to 6:30PM

 

Scientific Organizing Committee

• Jacopo Fumagalli (Universitat de Barcelona and ICCUB)
• Cristiano Germani (Universitat de Barcelona and ICCUB) - Chair
• Carlos Sopuerta (ICE-CSIC/IEEC)

Local Organizing Committee

• Anna Argudo (ICCUB)
• Esther Pallarés (ICCUB)

 

 

Acknowledgements

This event is part of the grant, Institut de Ciències del Cosmos, CEX2019-000918-M funded by MCIN/AEI/10.13039/501100011033.

This event is part of the grant Spanish Contribution to LISA: Instrument Development and Scientific Exploitation, PID2019-106515GB-I00, funded by MCIN/AEI/10.13039/501100011033.

Poster ICCUB School 2023 PBH.pdf

Right of information in relation to the data processing

Monday 26 June

08:30 → 09:15 Registration

09:15 → 09:30 Welcome

09:30 → 11:30 Pre-school: Basics of cosmological perturbation theory

Speaker: Jaume Garriga (ICCUB)

11:30 → 12:00 Break

12:00 → 13:00 Constraints on primordial black holes

Speaker: Florian Kuhnel (Ludwig-Maximilians-Universitaet)

Kuhnel, Florian - ICCUB - Bacelona - June 2023.pdf

Kuhnel, Florian - ICCUB - Bacelona - June 2023_.pdf

13:00 → 14:30 Lunch break

14:30 → 16:30 Enhancement mechanisms for cosmological perturbations

Speaker: Ana Achucarro (Leiden University)

16:30 → 17:00 Break

17:00 → 18:00 Constraints on primordial black holes

Speaker: Florian Kuhnel (Ludwig-Maximilians-Universitaet)

Tuesday 27 June

09:30 → 11:30 Enhancement mechanisms for cosmological perturbations

Speaker: Ana Achucarro (Leiden University)

11:30 → 12:00 Break

12:00 → 13:00 Constraints on primordial black holes

Speaker: Florian Kuhnel (Ludwig-Maximilians-Universitaet)

13:00 → 14:30 Lunch Break

14:30 → 16:30 Selected Talks

Conveners: Cristiano Germani (UB physics), Jacopo Fumagalli (ICCUB - Universitat de Barcelona)

14:30 Numerical simulations of stochastic inflation using importance sampling

Primordial black holes are expected to form from large, but rare, cosmological fluctuations in the tail of the probability distribution arising from inflation. I will present how importance sampling can be used to efficiently investigate the far, numerically expensive, probability tail of these fluctuations, finding non-perturbative deviations from Gaussianity. This is done by solving the first-passage time problem in the Langevin processes to find the distribution of the local duration of inflation in e-folds. By the stochastic-$\delta N$ formalism, these are related to the curvature perturbation at the end of inflation. What previously would take supercomputers weeks, or in principle even years, can be done in hours with just a single CPU using this approach.

Speaker: Joseph Jackson (University of Portsmouth)

importance_sampling_presentation_Barcelona_2023.pdf

14:50 Towards a non-perturbative description of inflation

In recent years, primodrial black holes (PBHs), i.e. black holes produced in the very early universe, have attracted much attention because of their important cosmological consequences. One of the mechanisms that can produce PBHs is the collapse of superhorizon large density inhomogeneities whenever they enter the horizon. These large inhomogeneities can be generated during inflation, reason why a non-perturbative (in terms of the amplitude of the inhomogeneities) description of inflation is of crucial importance in order to correctly describe the abundance of PBHs. In this talk I will explore some of the attempts to achieve such a non-perturbative description of inflation such as the \deltaN or stochastic formalism and their difficulties.

Speaker: Diego Cruces (ICCUB)

Presentation_PBH_school.pdf

15:10 Balancing the medium response in minimal warm inflation

Axion-like inflation models have for long been discussed as the radiative corrections that spoil many single-field models are avoided by virtue of its shift symmetry. In addition, the inflaton can generically have an axion-like coupling to non-abelian gauge bosons. It has been shown that this interaction automatically induces a non-diluting thermal bath during inflation leading to a warm-inflation scenario. The peculiarity of a medium response with two physical origins, vacuum and thermal dynamics, leads into interesting phenomenology to describe the early and later stages of inflation. In this work we will study the conditions where these models satisfy Planck constrains, and possibly generate the amplification of scalar and tensor perturbations at the later stages of inflation whenever the thermal contribution dominates.

Speaker: António Torres Manso (Universidad Granada)

Balancing_the_medium_response_in_minimal_warm_inflation.pdf

15:30 New method to detect continuous gravitational waves from inspiraling light primordial black holes

Primordial black holes can span a large range of masses depending on their time of formation. In particular, they can have subsolar masses and form binary systems in an efficient way. The inspiral phase can last for long periods of time (from hours to years) with a slow increase of frequency and, therefore, these signals are well suited to be searched with continuous gravitational waves methods. We present a new method based on the band sampled data (BSD) framework to specifically target this kind of signals. Additionally, we show an estimation of the sensitivity of the search and the computational cost associated to it.

Speaker: Marc Andrés Carcasona (IFAE)

pres_PBHschool.pdf

15:50 Superradiant pion clouds around primordial black holes

We show that highly spinning primordial black holes of mass M ∼ 10^12 kg, potentially born in a matter-dominated era after inflation, can produce clouds of pions in their vicinity via the su- perradiant instability, with densities up to that of nuclear matter. We discuss the electromagnetic signatures of this process, via neutral pion decay and charged pion annihilation into photons, com- puting in particular their contribution to the isotropic gamma-ray background. This allows us to place upper bounds on the abundance of such primordial black holes that are comparable to the ones obtained from Hawking evaporation. We also discuss the possibility of directly observing such clouds in high-redshift superclusters.

Speaker: Paulo Ferraz (University of Coimbra)

PauloFerraz_presentation_ICCBU2023.pdf

16:10 Diffuse emission from black hole remnants

At the end of its evaporation, a black hole may leave a remnant where a large amount of information is stored. We argue that the existence of an area gap as predicted by loop quantum gravity removes a main objection to this scenario. Remnants should radiate in the low-frequency spectrum. We model this emission and derive properties of the diffuse radiation emitted by a population of such objects. We show that the frequency and energy density of this radiation, which are measurable in principle, suffice to estimate the mass of the parent holes and the remnant density, if the age of the population is known.

Speaker: Mateo Pascual (Western University, London)

_Presentation Diffuse emission.pdf

16:30 → 17:00 Break

17:00 → 18:00 Constraints on primordial black holes

Speaker: Florian Kuhnel (Ludwig-Maximilians-Universitaet)

Wednesday 28 June

09:30 → 10:30 PBHs from highly non-Gaussian tails of the probability distribution

It has now become fully realized that the PBH formation depends crucially on the tails of the probability distribution function (PDF) of the curvature perturbation. In this talk, I will review some recently proposed models of inflation in which highly non-Gaussian tails appear in the PDF that can only be computed non-perturbatively, and discuss their implications.

Speaker: Misao Sasaki (IMPU)

10:30 → 11:00 Break

11:00 → 13:00 The statistics of primordial black holes

Speaker: Ravi Sheth (University of Pennsylvania)

13:00 → 14:20 Lunch Break

14:20 → 15:00 Selected Talks

Convener: Carlos Sopuerta (CSIC)

14:20 The ultraviolet limit of the power spectrum and Lagrangian perturbation theory

Understanding the non-linear evolution of Large Scale Structure (LSS) is a key challenge in contemporary cosmology. To this end, it is important to combine both numerical simulations and analytical approaches, such as perturbation theory of LSS. Recently, it has been understood that the power spectrum in a cold dark matter dominated Universe can be investigated via an expansion in inverse powers of the wavenumber. In this talk, I will discuss various aspects of this novel expansion. In particular, I will show how it relates to Lagrangian perturbation theory and use it to derive powerful constraints on the structure of the effective field theory of LSS.

Speaker: Jahmall Matteo Bersini (Kavli IPMU)

Bersini LSS talk.pdf

14:40 Primordial black holes as dark matter candidates in braneworld cosmology

In this talk I will present my current research on primordial black holes in (4+1) dimensional models. I will discuss how black hole properties - such as temperature, accretion rate and evaporation - change when one introduces an extra dimension. We are currently studying how these changes affect the range of masses in the dark matter window (f_PBH~1) and other observational signatures.

Speaker: Itziar Aldecoa Tamayo (University of Sussex / ICCUB)

15:00 → 15:15 Break

15:15 → 17:15 Primordial black holes formation, theory and simulations

Speaker: Albert Escrivà (Nagoya University)

Thursday 29 June

09:30 → 11:30 Gravitational waves signatures of primordial black holes

Speaker: Guillem Domènech (Leibniz University)

GWSofPBH_lectures.pdf

11:30 → 12:00 Break

12:00 → 13:00 The statistics of primordial black holes

Speaker: Ravi Sheth (University of Pennsylvania)

13:00 → 14:00 Lunch Break

14:00 → 16:00 LISA capabilities in the context of PBH physics

Speaker: Natalia Korsakovoa (APC)

16:00 → 16:30 Break

16:30 → 18:30 Primordial black holes formation, theory and simulations

Speaker: Albert Escrivà (Nagoya University)

Friday 30 June

09:30 → 11:30 Gravitational waves signatures of primordial black holes

Speaker: Guillem Domènech (Leibniz University)

11:30 → 12:00 Break

12:00 → 13:00 LISA capabilities in the context of PBH physics

Speaker: Natalia Korsakova (APC)

13:00 → 14:30 Lunch Break

14:30 → 16:30 The statistics of primordial black holes

Speaker: Ravi Sheth (University of Pennsylvania)

16:30 → 16:45 The latest updates from the pulsar timing array community

Convener: Nataliya Porayko (Milano Bicocca University)

16:45 → 17:15 Break

17:15 → 18:15 LISA capabilities in the context of PBH physics

Speaker: Natalia Korsakova (APC)