Spherically symmetric spacetime

In physics, spherically symmetric spacetimes are commonly used to obtain analytic and numerical solutions to Einstein's field equations in the presence of radially moving matter or energy. Because spherically symmetric spacetimes are by definition irrotational, they are not realistic models of black holes in nature. However, their metrics are considerably simpler than those of rotating spacetimes, making them much easier to analyze. Spherically symmetric models are not entirely inappropriate: many of them have Penrose diagrams similar to those of rotating spacetimes, and these typically have qualitative features (such as Cauchy horizons) that are unaffected by rotation. One such application is the study of mass inflation due to counter-moving streams of infalling matter in the interior of a black hole. A spherically symmetric spacetime is a spacetime whose isometry group contains a subgroup which is isomorphic to the rotation group SO(3) and the orbits of this group are 2-spheres (ordinary 2-dimensional spheres in 3-dimensional Euclidean space). The isometries are then interpreted as rotations and a spherically symmetric spacetime is often described as one whose metric is "invariant under rotations". The spacetime metric induces a metric on each orbit 2-sphere (and this induced metric must be a multiple of the metric of a 2-sphere). Conventionally, the metric on the 2-sphere is written in polar coordinates as and so the full metric includes a term proportional to this. Spherical symmetry is a characteristic feature of many solutions of Einstein's field equations of general relativity, especially the Schwarzschild solution and the Reissner–Nordström solution. A spherically symmetric spacetime can be characterised in another way, namely, by using the notion of Killing vector fields, which, in a very precise sense, preserve the metric. The isometries referred to above are actually local flow diffeomorphisms of Killing vector fields and thus generate these vector fields.

Concentration compactness for critical radial wave maps

Joachim Krieger, Elisabetta Chiodaroli

We consider radially symmetric, energy critical wave maps from (1 + 2)-dimensional Minkowski space into the unit sphere

\mathbf{S}^m

, m≥1, and prove global regularity and scattering for classical smooth data of finite energy. In addition, we establish a ...

2018

Spherically symmetric spacetime

Asymptotic dynamic for dipolar Quantum Gases below the ground state energy threshold

Concentration compactness for critical radial wave maps

Microlensing of the broad line region in 17 lensed quasars

Microlensing of the broad line region in 17 lensed quasars

Concentration compactness for critical radial wave maps

Asymptotic dynamic for dipolar Quantum Gases below the ground state energy threshold