Astrophysics

In this talk, we introduce and solve the characteristic gluing problem for the Einstein vacuum equations. We prove that obstructions to characteristic gluing come from an infinite-dimensional space of conservation laws along null hypersurfaces for...

Abstract 1: Reionization of the intergalactic medium remains one of the most mysterious questions in the research of cosmology. While the first generation of stars (Pop-III) likely ionize the universe at 1-10% level at z>15, the second generation of...

Each week, we hold a relatively informal seminar/discussion series with an emphasis on extra-galactic and large-scale structure astrophysics.

During Galread a leader/visitor presents a recent paper to the discussion group. The PDF of the paper is...

Near-Earth space has become increasingly valuable and its use for civil (e.g., scientific), commercial, and military purposes has grown enormously in recent years. This growth has been driven in part by a rapid decrease in space-launch costs, which...

Many modern materials feature a “Planckian metal”: a phase of electronic quantum matter without quasiparticle excitations, and relaxation in a time of order Planck's constant divided by the absolute temperature. The semiclassical theory of black...

The vast majority of known exoplanet systems are billions of years old. Over these long lifetimes, chaotic gravitational interactions among the planets can lead to violent collisions and restructurings of their orbits. Indeed, the observed sample...

Although today’s nuclear arsenals are not much in the news, they pose enormous risks for all humanity. Moreover, many treaties that have reduced the threat of nuclear weapons are now being abandoned, and enormous resources are scheduled to be spent...

The outer layers of molecular clouds are submitted to the ambient radiation field and the presence of charged species favours their coupling to the ambient magnetic field. In particular, charged dust grains may affect the turbulent state and the...