Speaker
Balt Van Rees
(École Polytechnique)
Description
Is there any room for non-trivial unitary and conformal defects in the theory of a single free massless scalar field? And what about boundaries? We use the free scalar equation of motion and the structure of the bulk-to-defect operator expansion to rule out the existence of such defects in several (co-)dimensions. For boundaries we are led to a non-trivial system of crossing equations that we analyze numerically in four bulk dimensions. We show that large regions of parameter spaces are excluded, but a ‘kink’ in the numerical bounds obeys all our consistency checks and might be an indication of a new conformal boundary condition.
