Théorie

Multimessengers from magnetized turbulent plasmas in extreme environments

Highly magnetized environments around compact astrophysical sources (black holes, neutron stars) and their relativistic outflows provide exquisite conditions for accelerating charged particles to very high energies (TeV to PeV and beyond; VHE) and producing multimessenger signals (e.g. photons and neutrinos). Indeed, the pervasive turbulence can ensure efficient stochastic particle acceleration, while the ambient backgrounds provide ideal targets for radiative and hadronic interactions.

Holography and Phases of Strongly Coupled Matter

The research project  will focus on applications of the holographic gauge/gravity duality to the description of the dense state of strongly interacting  matter, and in particular to static and dynamical properties of neutron stars.

Black holes, turbulence and multi-messenger astrophysics

The immediate vicinity of black holes provides exquisite conditions for accelerating particles to extremely high energies, up to PeV and beyond. One likely mechanism is via the collisionless plasma turbulence that is expected in the black hole environment, and whose random electromagnetic fields promote efficient stochastic particle acceleration (diffusion in energy space). Accelerated particles add viscosity to the flow, and therefore damp the turbulence that feeds them, giving rise to an interesting nonlinear interaction between particles and electromagnetic fields.

Neutrinos: from the discovery of the diffuse supernova background to entanglement

Neutrinos are elementary massive particles with mixings. They can change flavor while propagating. Weakly interacting, neutrinos tell us about the primordial Universe and dense environments, such as exploding stars (core-collapse supernovae) or binary compact objects (neutron star-neutron star, black hole-neutron star). Such neutrinos undergo unexpected flavor phenomena and can be unique probes for new physics.

Lancement d'ACME, un projet construit par et pour les communautés des astroparticules et de l'astronomie

Les 16 et 17 septembre s'est tenue à Paris la réunion de lancement du Astrophysics Centre for Multimessenger studies in Europe - ACME. Ce projet HORIZON-INFRA-2023-SERV-01 financé par l'UE et coordonné par le Centre national de la recherche scientifique CNRS vise à réaliser une ambitieuse optimisation coordonnée à l'échelle européenne de l'accessibilité et de la cohésion entre plusieurs infrastructures de recherche de pointe en matière d'astroparticules et d'astronomie, offrant un accès aux instruments, aux données et à l’expertise, axés sur la nouvelle science de l'astrophysique multi-messagers.

Neutron star physics, neutron star mergers, near-extremal black holes and effective theories near absolute zero.

This project involves using techniques from the AdS/CFT correspondence (known also as holography) to understand


(a) The non-trivial phases in the QCD phase diagram, involving non zero baryon number density as well as non-zero isospin density.


(b) The statics and dynamics in non-trivial phases relevant for neutron stars, where very low temperatures are relevant.


The holographic solutions dual to such phases involve near-extremal black holes that have unusual features compared to standard black holes: although for such solutions hydrodynamics

Dynamique des systèmes binaires en relativité générale et perturbations des trous noirs en gravité modifiée

La relativité générale est une théorie plus que centenaire qui a survécu, jusqu’à présent, à toutes les mises à l’épreuve observationnelles. Avec les détections des ondes gravitationnelles émises par des coalescences de trous noirs ou d’étoiles à neutrons s’amorce une nouvelle étape dans l’histoire de la relativité générale : l’ère de l’astronomie gravitationnelle.

Théorie