Théorie

Unveiling Positrons in Galactic Cosmic Rays

The spectrum of positrons in cosmic rays is currently measured with unprecedented precision by AMS-02 up to TeV energies, and represents an unique probe for the local properties of our Galaxy. Currently, its interpretation is still debated, especially for the excess above 10 GeV which suggests the presence of a local, primary source.
Recently, the observation of extended gamma-ray halos around Galactic pulsars has opened a new window to constrain the acceleration and propagation of positrons in our Galaxy.

Quantum orientations in the plane: Malus’ law (1808) and Stokes parameters (1852) for polarisation of light viewed as a quantum measurement

Two aspects of Positive Operator Valued Measures (POVM) on the Euclidean plane (a basic Hilbert space!) are presented, namely their status as quantum observables and their role as quantizers in the integral quantization procedure. The compatibility of POVMs in the ensuing quantum formalism is discussed, and a Naimark dilation is found for the quantum operators. The relation with Toeplitz quantization is explained. Within this framework, we describe the linear polarization of the light with the use of Stokes parameters and its interaction with a polariser as a quantum measurement (Malus’ law).

Observing quantum gravity in gravitational waves

Gravity can be embedded into a renormalizable theory by means of adding quadratic in curvature terms. 
However, this at first leads to the presence of the Weyl ghost. It is possible to get rid of this ghost if the 
locality assumption is weakened and the propagator of the graviton is represented by an entire function 
of the d'Alembertian operator without new poles and zeros. Models of this type admit a cosmological 
solution describing the R^2, or Starobinsky, inflation. We study graviton production after inflation in 

Cosmic Rays in the Multi-Messenger Era

The 'Cosmic Rays  in the Multi-Messenger Era' conference aims to bring together the scientific communities working on high-energy cosmic rays, from an experimental point of view as well as from a theoretical and phenomenological sides. In addition to detailed presentations of theoretical models dealing with the production of cosmic rays and secondary neutrinos and gamma-rays, the conference will include reviews of the latest experimental results as well as prospects for the next decade.

DEADLINE FOR REGISTRATION: NOVEMBER 20TH, 2022

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