Seminar A. Sfondrini

Title:
T-Tbar deformations and string theory

Abstract:
An interesting way to build new interesting models in theoretical physics is to deform some well-understood model in such a way as to preserve some of its special properties. A few years ago, Sasha Zamolodchikov introduced the idea of deforming two-dimensional quantum field theories by a composite operator corresponding to the determinant of the stress-energy tensor, det[T^{\mu\nu}]. This irrelevant deformation has been called "T-Tbar" (which is a bit of a misnomer) and turns out to have remarkable properties. In particular it is solvable, meaning that we can construct the energy spectrum of a deformed theory based on that of the undeformed one. This lead to many interesting applications to deformations of conformal and integrable theories, to string theory, and to AdS/CFT in low dimension. I will review some of these applications with special emphasis with the relation of these deformations with (super)string theory in light-cone gauge.

The talk will be somewhat based on arXiv:1804.01998 and arXiv:1811.00533 but include plenty of review.

.