Solitons on compact and non-compact spaces in large non-commutativity

Abstract

We study solitons at the minima of scalar fieldpotentials for Moyal spaces and torii in largenon-commutativity and interpret these solitons in termsof non-BPS D-branes of string theory. We derive a massspectrum formula linking different D-branes together onquantum torii and suggest that it describes generalsystems of D-brane bound states, which extend the\\mbox{{\\rm D}2-{\\rm D}0} one. Then we propose a shapefor the effective potential approaching thesequasi-stable bound states. We give the gauge symmetriesof these systems of branes and show that they depend onthe quantum torii representations.