Euclidean Wormholes and Holography

Wormholes are exotic solutions of General Relativity that still challenge our physical intuition. In this talk I will first review and distinguish various types of wormholes along with their expected physical properties. I will then focus on asymptotically AdS wormhole solutions in the context of holography. I will explain how to compute correlation functions of local operators as well as non local observables such as correlation functions of Wilson loops on the distinct boundaries and discuss their behavior.

Numerical Simulations of Gravitational Waves from Early-Universe Turbulence

Theory group virtual seminar by Alberto Roper Pol on Tuesday 22nd of September at 14:00h.

Title: Numerical Simulations of Gravitational Waves from Early-Universe Turbulence

The European Low Frequency Survey: observing the radio sky to understand the beginning of the Universe

Nowadays the leading contender to understand the initial conditions of the Big Bang is inflation, which predicts the existence of a primordial background of gravitational waves that must have left its imprint in the CMB polarization: the so-called B-modes. The main difficulty in measuring the B-modes comes not just from its sheer faintness but from the fact that many other objects in the universe also emit polarized microwaves.

Free falling with a pulsar in a triple system

Resonances in black hole spacetimes and neutron stars

Joint seminar organized by APC (University of Paris) and Service de Physique Théorique (ULB, Brussels)

Gravitational radiation from a binary black hole coalescence in Einstein-scalar-Gauss-Bonnet gravity

Joint seminar organized by APC (University of Paris) and Service de Physique Théorique (ULB, Brussels)

The H0 tension and non-minimal couplings to gravity

Reconstruction of neutrino events in the MicroBooNE detector

MicroBooNE is a Liquid Argon Time Projection Chamber (LArTPC) neutrino experiment on the Booster Neutrino Beamline at the Fermi National Accelerator Laboratory, with an 85-tonne active mass.
One of MicroBooNE’s primary physics goals is to investigate the excess of electron neutrino events seen by MiniBooNE in the [200-600] MeV range.
MicroBooNE will constrain the intrinsic electron neutrino component of the beam by measuring the muon neutrino spectrum.

Séminaire Gravitation - Giulia Cusin: presentation material

This page contains the presentation material of the seminar given by Dr Giulia Cusin on the 24th of February 2020:

Astrophysical background of gravitational waves: anisotropies, polarization and cross-correlations with cosmological observables.
Available for APC members on request of the speaker.

Vainshtein screening for slowly rotating stars

We study the Vainshtein mechanism in the context of slowly rotating stars in scalar-tensor theories.
While the Vainshtein screening is well established for spherically symmetric spacetimes, we introduce a slow rotation of the source and examine its validity in the axi-symmetric case.
We solve for the frame-dragging function accounting for the slow rotation and show that the deviations from the general relativity (GR) solution are screened in the weak-field approximation, meaning the solution for the frame-dragging function is the same as GR to leading order.

LABORATOIRE

ASTROPARTICULE & COSMOLOGIE

Séminaire