Nuclear Physics B340 (1990) 33—55 North-Holland SUPERSTRINGS AND SOLITONS Atish DABHOLKAR Joseph Henry Laboratories, Princeton Universily, Princeton, NJ 08544, USA Gary GIBBONS* Institut d’Hautes Etudes Scientifiques, 35, Route de Chartres, F-91440 Bures-sur-Yvette, France Jeffrey A. HARVEY ** Enrico Fermi Institute, Universily of Chicago, 5640 Ellis Avenue, Chicago, IL 60637, USA Fernando RUIZ RUIZ DAMTP, University of Cambridge, Silver Street, Cambridge CB3 9EW~ UK Received 9 March 1990 A low-energy analysis of macroscopic superstrings is presented and various analogies between these superstrings and solitons in supersymmetric theories are discussed. These include the existence of exact multi-string solutions of the low-energy supergravity super-Yang—Mills equations of motion and a Bogomol’nyi bound for the energy per unit length which is saturated by these solutions. Arguments are presented that these features will persist to all orders in a. The connection between chiral fermion zero modes on the string and partially broken supersym- metry is also discussed. 1. Introduction Most studies of classical solutions to superstring theory have focused on solu- tions which correspond to compactification of some number of spatial dimensions with the remaining dimensions being described by a flat Minkowski space-time. The correspondence between these solutions and superconformal field theory is now well understood. Recently there has been interest in expanding the study of classical solutions to include those with nontrivial dependence on the noncompact Minkowski coordinates as well [1—3]. * Permanent address: DAMTP, University of Cambridge, Silver Street, Cambridge CB3 9EW, UK. ** Permanent address: Jadwin Hall, Princeton University, Princeton, NJ 08544, USA. 0550-3213/90/$03.50 © Elsevier Science Publishers B.V. (North-Holland)