Dbrane phase transitions and monodromy in K-theory

Majumder and Sen have given an explicit construction of a first order phase transition in a non-supersymmetric system of Dbranes that occurs when the B-field is varied. We show that the description of this transition in terms of K-theory involves a bundle of K groups of non-commutative algebras over the Kahler cone with nontrivial monodromy. Thus the study of monodromy in K groups associated with quantized algebras can be used to predict the phas e structure of systems of (non-supersymmetric) Dbranes. (C) 2000 Elsevier S cience B.V. All rights reserved.