Semiclassical String Solutions on deformed NS5-brane Backgrounds and New Plane wave

Abstract

We study different Penrose limits of supergravity solution of NS5-brane in the presence of RR field. Although in the case of NS5-brane we get a 4-dimensional plane wave, in the case with RR field we will get two different plane waves; a 4-dimensional and a 3-dimensional one. These plane wave solutions are the backgrounds that a particular string solution feels at one loop approximation. Using the one loop correction one can identify a particular subsector of LST/deformed LST which is dual to type II string theories on these plane waves.