{"id":713683,"date":"2021-11-22T13:40:17","date_gmt":"2021-11-22T13:40:17","guid":{"rendered":"https:\/\/projects.ift.uam-csic.es\/holotube\/?p=713683"},"modified":"2021-12-01T11:34:15","modified_gmt":"2021-12-01T11:34:15","slug":"november-30-central-charges-of-conformal-boundaries-and-defects-by-andrew-obannon","status":"publish","type":"post","link":"https:\/\/projects.ift.uam-csic.es\/holotube\/2021\/11\/22\/november-30-central-charges-of-conformal-boundaries-and-defects-by-andrew-obannon\/","title":{"rendered":"November 30: “Central Charges of Conformal Boundaries and Defects” by Andrew O’Bannon"},"content":{"rendered":"\n
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Date : November 30, 2021, 16:00 CET<\/strong><\/p>\n\n\n\n

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Andrew O’Bannon<\/strong><\/strong> (U. of Southampton)<\/p>\n<\/div><\/div>\n\n\n\n

Link:<\/strong> https:\/\/zoom.us\/j\/98260147834?pwd=VW5BQStqUGUrUFFzWG1jL2tuWXJoZz09<\/a><\/p>\n\n\n\n

Title:<\/strong> Central Charges of Conformal Boundaries and Defects<\/p>\n\n\n\n

Abstract<\/strong>:  In a 2d conformal field theory (CFT) the central charge is defined from the Virasoro algebra. Crucially, the central charge obeys the c-theorem, a powerful, universal, non-perturbative constraint: the central charge must decrease under renormalization group flows. The central charge appears in many other places too, such as stress tensor two-point functions, thermal entropy, entanglement entropy, and more. All of these indicate that the central charge counts CFT degrees of freedom. However, what happens with a 2d boundary of a 3d CFT, or a 2d conformal defect in a higher-dimensional CFT? Generically in these cases no Virasoro algebra is present. Can we still define a central charge? If so, in what quantities does it appear? Can we prove a c-theorem? These questions may be crucial for graphene with a boundary, surface operators in CFTs, and many other systems. In this talk I will summarize the state of the art in this area, including examples and open questions.<\/p>\n<\/div><\/div>\n\n\n