Integrable Model of Boundary Interaction: The Paperclip

TL;DR

This paper introduces an integrable boundary interaction model in 2D quantum field theory with a boundary constraint called the 'paperclip brane', providing exact solutions for the disk partition function.

Contribution

It proposes an exactly solvable boundary interaction model in 2D QFT with a novel boundary constraint, maintaining integrability despite breaking conformal invariance.

Findings

Exact expression for the disk partition function derived

Boundary state overlaps expressed via differential equations

Model preserves integrability with boundary interaction

Abstract

We consider a model of 2D quantum field theory on a disk, whose bulk dynamics is that of a two-component free massless Bose field (X,Y), and interaction occurs at the boundary, where the boundary values (X_B, Y_B) are constrained to special curve - the ``paperclip brane''. The interaction breaks conformal invariance, but we argue that it preserves integrability. We propose exact expression for the disk partition function (and more general overlap amplitudes < P | B > of the boundary state with all primary states) in terms of solutions of certain ordinary linear differential equations.