Integrable Model of Boundary Interaction: The Paperclip
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 (XB, YB) 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.
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