We discuss the open string one-loop partition function in the tachyon condensation background of an unstable D-brane system. We evaluate the partition function by using the boundary-state formulation and find that it is in complete agreement with the result obtained in the boundary string field theory. This suggests that the open string higher loop diagrams may be produced consistently by using a closed string field theory, where the D-brane plays the role of a source for the closed string field.
- Algebraic methods in string theory
- Canonical quantization
- Nonperturbative techniques
- String field theory
- Strings extended classical solutions
- Theory of fundamental strings