String field theory --- a second quantized formalism of string theory --- has flourished as a field over the past twenty years with many new results in number of directions. From physics perspective, it provides us with insights ranging from the fundamental understanding of background instabilities (via so called tachyon condensation) to mass renormalization of the massive states of the string. From mathematical perspectives, it relies on concepts from 17th century mathematics to fusion categories and homotopy algebras, often providing new generalizations and new insights.
This PhD project should focus mostly on the rich interplay between (known or yet to be constructed) classical solutions of open and closed string field theory, and more traditional approaches via 2D conformal field theory. Possible avenues comprise numerical explorations, analytic or algebraic constructions of solutions, construction of observables in string field theory, CFT studies of new types of boundary conditions or defects, applications of homotopy algebras for constructing novel actions etc.