Dilaton Condensation in Cubic Open String Field Theory

We construct an exact and finite classical solution in cubic open string field theory. The classical solution has a well-defined Fock space expression. Through the redefinition of a string field, the string field theory expanded around the classical solution can be transformed into the theory with a different coupling constant, where other backgrounds are unchanged. Therefore, the classical solution represents the condensation of the dilaton in cubic open string field theory. E-mail address: [email protected] E-mail address: [email protected]