Théorie

LHAASO Discovers Black Hole Driven PeVatrons (μ-Quasars) and Precisely Measures the New Component in the Proton-Helium Spectra

LHAASO discovers “high energy” component in the CR proton-helium spectra at the “knee”, indicates new population of CR sources. It is clearly differ from the “low energy” component which is traditionally regarded as originated from supernova remnants. LHAASO has provided strong evidences of the HECRs from SNRs, however limited Emax “proton knee”. The new HE population most likely consists of black holes, more specifically μ-Quasars. The extreme case is Cgy X-3, the historical super-star that ignited the whole TeV γ-astronomy. Now LHAASO found it a super-PeVatron. Surrounding it, the huge LHAASO Bubble has still very mystery origin. Future experiments are highly anticipated, namely higher spatial resolution in γ-source investigation in depth and ultimately identification of their companion neutrino emissions.

Workshop on Holography and Dense Matter 2026

The workshop will focus on applications of the gauge/gravity duality to compact objects and gravitational waves. The purpose is to bring together  researchers  from AdS/CFT, QCD and GR to have an open an informal discussion, point out the interesting open problems and discuss where holography can be useful and how it can interface with other techniques.

For more information, see the workshop website 

https://indico.in2p3.fr/event/37825/ 

Gravitational Tidal Matching and Elliptic Curves

I will discuss tidal Love numbers, their formulation within effective field theory, and their relevance for gravitational-wave physics. I will then introduce an on-shell approach to computing Love numbers through an effective wave equation. Finally, I will present ongoing work with Simon Caron-Huot, Miguel Correia, and Anna Wolz on the emergence of elliptic sectors in gravitational wave scattering.

Positivity with long-range interactions

Long-range interactions, mediated for instance by photons and/or gravitons, force exclusive S-matrix elements to vanish in D=4 flat space-time, due to infrared divergences. This poses a challenge to programs, such as positivity and S-matrix bootstrap, that directly rely on the properties of 2-to-2 amplitudes. In this talk, I will introduce stripped amplitudes as IR-finite, analytic, crossing-symmetric and Regge-behaved avatars of standard amplitudes, associated with a physical detector scale \Lambda. In the regime in which the latter is taken exponentially small than all other scales, they also satisfy a form of unitarity, allowing to derive IR-finite positivity bounds on EFTs, in presence of long-range interactions.

Stochastic Differential Equations - A powerful tool for cosmic ray transport

Stochastic differential equations (SDEs) can be used to describe cosmic ray transport in an efficient way suited for modelling on modern computing architectures. In this talk I will give an overview on how to transform Fokker-Planck (partial differential) equations into their corresponding set of SDEs and show how to solve them numerically.

Open Effective Field Theories for the early and late universe

Dissipation and noise arise across physics, from condensed matter to cosmology, whenever a system evolves in the presence of an unknown medium. The Schwinger–Keldysh formalism provides a systematic framework for describing such non-equilibrium and open-system dynamics. In this talk, I present an approach to cosmology that combines General Relativity with the Schwinger-Keldysh formalism. I show how symmetry, locality, and unitarity constrain the possible forms of dissipation and noise, and use these principles to derive the most general conservative and dissipative dynamics of scalar and tensor perturbations in a Friedmann–Lemaître–Robertson–Walker background. I then discuss how dissipative effects leave characteristic imprints on primordial non-Gaussianities and gravitational waves, and conclude with future prospects for dissipative dark sectors in the late universe.
Théorie