Seminar detail: Nonrenormalization Theorem for N = (4, 4) Interface Entropy

Date&Time	Wed Apr 16 2025 (10:30 - 11:30)
Speaker	Mianqi Wang
Affiliation	University of Texas, Austin
Title	Nonrenormalization Theorem for N = (4, 4) Interface Entropy
Abstract	Conformal interfaces between 2D conformal field theories (CFT) are characterized by the entanglement entropy (information) and energy transmission quantities. Among them, the effective central charge c_eff, interface entropy g, and energy transmission coefficient cLR have been studied extensively. Bottom-up and top-down models of holographic interface CFT allow for the calculation of these quantities in bulk gravity and boundary CFT. In particular, a class of Janus-like solutions with half-BPS interfaces yield exactly matching results for c_eff, c_LR and g in the supergravity limit and orbifold CFT limit, in contrast to the results with non- BPS interfaces. This agreement supports nonrenormalization conjectures and highlights the protective role of supersymmetry. In this talk, we address the nonrenormalization theorem for g. We derive a formula for the half-BPS interface entropy between any pair of N = (4,4) theories on the same conformal manifold. This generalizes the diastasis formula derived in arXiv:1311.2202 for N = (2,2) theories, which is restricted to the conformal submanifolds generated by either chiral or twisted chiral multiples of N = (2,2) supersymmetry. To derive the N = (4,4) formula, we use the fact that the conformal manifold of N = (4,4) theories is symmetric and quaternionic-K ̈ahler and that its isotropy group contains the SU(2) ⊗ SU(2) external automorphism of the N = (4, 4) superconformal algebra. As an application of the formula, we prove the observation in arXiv:1005.4433 that the interface entropy for half-BPS Janus solutions in type IIB supergravity on AdS_3×S^3×T^4 coincides with the corresponding quantity in their free conformal field limits.
Remarks	Online
Slide/Video