Superstring gravitational wave backgrounds with spacetime supersymmetry

Elias Kiritsis, Costas Kounnas, Dieter Lüst
1994 Physics Letters B  
We analyse the stringy gravitational wave background based on the current algebra E c 2 . W e determine its exact spectrum and construct the modular invariant v acuum energy. The corresponding N=1 extension is also constructed. The algebra is again mapped to free bosons and fermions and we show that this background has N=4 (N=2) unbroken spacetime supersymmetry in the type II (heterotic case).
doi:10.1016/0370-2693(94)91059-6 fatcat:5zyol3y5yzeenn4odnguhjxese