On horizons and plane waves

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...

On General Plane Fronted Waves. Geodesics

A general class of Lorentzian metrics, M0 ×R, 〈·, ·〉z = 〈·, ·〉x + 2 du dv + H (x, u) du2, with (M0, 〈·, ·〉x ) any Riemannian manifold, is introduced in order to generalize classical exact plane fronted waves. Here, we start a systematic study of their main geodesic properties: geodesic completeness, geodesic connectedness and multiplicity causal character of connecting geodesics. These results ...

String Theory on Dp-plane waves

We study the spectrum of solvable string models on plane waves descending from non-conformal Dp-brane geometries. We mainly focus on S-dual F1/D1-waves in type IIB and type I/heterotic 10D superstrings. We derive the Kaluza-Klein spectrum of N = 1, 2 10D supergravities on D1/F1-waves. We compute helicity supertraces counting multiplicities and R-charges of string excitations in the plane wave g...

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...