CNRS researcher, CPHT, Ecole
Polytechnique, Black Hole Initiative Visiting Scholar
Title: On the distinguishability of black hole microstates
Abstract: A challenging question in the context of the information paradox is how to distinguish black hole microstates without having access to the entire spacetime. In the context of holography, one can ask how one can distinguish microstates of a black hole in anti-de Sitter space by measurements performed in the dual conformal field theory. I will discuss one of the most powerful tools available for characterizing the distinguishability of two quantum states which has recently found broad application in holography: the relative entropy. I will compute its average value over the ensemble of microstates for the M=0 BTZ black hole and discuss its implication for the distinguishability of the microstates from the black hole.
Title: Discovery and Opportunity in the X-ray Time Domain
Abstract: Ambitious X-ray observatories have enabled a rapid expansion in our knowledge of the X-ray time domain. With state-of-the-art facilities like Chandra, XMM Newton, and Swift performing surveys over a decade and counting, variability catalogs are increasingly rich. Meanwhile, high time resolution from the likes of NuSTAR and NICER (and RXTE before them) continue to uncover new physics in individual systems. These efforts have lead to the discovery of high-energy EM counterparts to the first binary neutron star merger detected via gravitational waves, a likely pulsar-ULX connection, possible magnetar oscillations, X-ray flares from the closest supermassive black hole, Sgr A*, and enabled reverberation mapping of AGN, to name only a few. I will review a few highlights from the X-ray time domain and briefly describe what we hope to achieve with upcoming and proposed X-ray missions.