title: Constraint on Defect and Boundary Renormalization Group Flows.
abstract: A conformal field theory (CFT) in dimension d≥3 coupled to a planar, two-dimensional, conformal defect is characterized in part by a "central charge" b that multiplies the Euler density in the defect's Weyl anomaly. For defect renormalization group flows, under which the bulk remains critical, we use reflection positivity to show that b must decrease or remain constant from the ultraviolet to the infrared. Our result applies also to a CFT in d=3 flat space with a planar boundary.
authors.affiliation: C.N. Yang Institute for Theoretical Physics, SUNY Stony Brook, Stony Brook, New York 11794, USA.
authors.forename: Kristan
authors.initials: K
authors.lastname: Jensen
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
authors.forename: Andy
authors.initials: A
authors.lastname: O'Bannon