Multi-spin string solutions in AdS black hole and confining backgrounds

We study semi-classical multi-spin strings in the non-supersymmetric backgrounds of Ads black hole and Witten's confining model. We consider constant radius strings with rotations along the isometries of the backgrounds. In the Ads black hole, solutions exist only if there is a non-zero spin in the black hole part. In contrast with the Ads background, we find solutions which although have no rotation in the S-5 part, have a regular. expansion in the expression for large energy. In the near-extremal D-3 and D-4 backgrounds, we find that strings have to be located on the confining wall. We also discuss the stability of solutions by considering the fluctuation Lagrangians. (C) 2004 Elsevier B.V. All rights reserved.