Found 2 result(s)

25.06.2020 (Thursday)

Exact g-functions

Journal Club Joao Caetano (Simons Center)

at:
15:00 Other
room Zoom, instructions in abstract
abstract:

The g-function is a measure of degrees of freedom associated to a boundary of two-dimensional quantum field theories. In integrable theories, it can be computed exactly in a form of the Fredholm determinant, but it is often hard to evaluate numerically. In this paper, we derive functional equations---or equivalently integral equations of the thermodynamic Bethe ansatz (TBA) type---which directly compute the g-function in the simplest integrable theory; the sinh-Gordon theory at the self-dual point. The derivation is based on the classic result by Tracy and Widom on the relation between Fredholm determinants and TBA, which was used also in the context of topological string. As a side result, we present multiple integrals of Q-functions which we conjecture to describe a universal part of the g-function, and discuss its implication to integrable spin chains. ------------------------- Part of London Integrability Journal Club. New participants please register at integrability-london.weebly.com to receive the link.

06.12.2017 (Wednesday)

Handling Handles: Nonplanar Integrability

Triangular Seminar Joao Caetano (ENS, Paris)

at:
15:00 KCL
room S-1.27
abstract:

TRIANGULAR SEMINAR: We propose an integrability setup for the computation of correlation functions of gauge-invariant operators at any value of the 't Hooft coupling and at any order in the large Nc 't Hooft expansion in N = 4 SYM theory. In this multi-step proposal, one polygonizes the string worldsheet in all possible ways, hexagonalizes all resulting polygons, and sprinkles mirror particles over all hexagon junctions to obtain the full correlator. We test our integrability-based conjecture against a non-planar four-point correlator of large half-BPS operators at one and two loops.