HET seminar: Balázs Pozsgay – University of Copenhagen

HET seminar: Balázs Pozsgay

Speaker: Balázs Pozsgay

Title: One-point functions in defect CFT, Integrable Matrix Product States, and boundary integrability


In a CFT with a defect the scaling operators can have non vanishing
mean values. At one loop order in planar N=4 SYM the normalization
constants of these one-point functions are given by the overlaps
between the corresponding Bethe states and a particular Matrix Product
State (MPS). These MPS are not eigenstates of the spin chain, but they
display very special features: the overlaps are non-zero only for
parity symmetric Bethe root configurations, and can be expressed in a
factorized form. In this talk we focus on the algebraic properties of
these MPS: we explain their relation to boundary integrability and the
twisted Yangian, and show how they can be obtained from the twisted
Boundary Yang-Baxter relation.