Plane waves and spacelike infinity

Spacelike matching to null infinity

We present two methods to include the asymptotic domain of a background spacetime in null directions for numerical solutions of evolution equations so that both the radiation extraction problem and the outer boundary problem are solved. The first method is based on the geometric conformal approach, the second is a coordinate based approach. We apply these methods to the case of a massless scala...

On the differentiability conditions at spacelike infinity

We consider space-times which are asymptotically flat at spacelike infinity, i. It is well known that, in general, one cannot have a smooth differentiable structure at i, but have to use direction dependent structures. Instead of the oftenly used C-differentiabel structure, we suggest a weaker differential structure, a C + structure. The reason for this is that we have not seen any completions ...

Reflection and Transmission of Plane Waves at Micropolar Piezothermoelastic Solids

The present investigation analysis a problem of r­­­eflection and transmission at an interface of two micropolar orthotropic piezothermoelastic media. The basic equations and constitutive relations for micropolar orthotropic piezothermoelastic media for G-L theory are derived. The expressions for amplitude ratios corresponding to reflected and transmitted waves are derived analytically. The eff...

Plane Waves and Penrose Limits

Plane Waves and Vacuum Interpolation

A 1 2 -BPS family of time dependent plane wave spacetimes which give rise to exactly solvable string backgrounds is presented. In particular a solution which interpolates between Minkowski spacetime and the maximally supersymmetric homogeneous plane wave along a timelike direction is analyzed. We work in d = 4, N = 2 supergravity, but the results can be easily extended to d = 10, 11. The confor...