A Note on Nonperturbative Instability in String Theory

We investigate the possibility that stringy nonperturbative instabilities are described by worldsheet methods. We focus on the case of open bosonic string theory, where the D-instanton plays a role of the bounce, i.e. it describes barrier penetration. In the process, we compute the exponential factor in a decay probability.Comment: 5 pages, 1 figur

Towards complex(rational) powers of free fields, generalized βγ\beta\gamma systems and non-polynomial quantum field theory

The $\beta\gamma$ system is generalized by complex(rational) powers of the fields, which leads to a corresponding extension on the Fock space. Two different approaches to compute the Green functions of the physical operators are proposed. First the complex(rational) powers are defined via an integral representation,that allows to compute the conformal blocks, Green functions and structure constants of OPA. Next an approach based on a system of recursion equations for the Green functions is developed. A number of solutions of the system is found. A lot of possible applications is briefly discussed.Comment: 20 pages, 3 figures, LaTex, HUB-IEP-94/