Time: 10:00-11:30  (Beijing time), Wednesday, 2025/03/19 (March 19)

Location: Building 7, Room 401, UCAS Zhong-Guan-Cun Campus

Speaker: Dongsheng Ge (Osaka University)

Abstract:

We consider a composite defect system where a lower-dimensional defect (sub-defect) is embedded to a higher-dimensional one, and examine renormalization group (RG) flows localized on the defect. A composite defect is constructed in the (3 − ϵ)-dimensional free O(N) vector model with line and surface interactions by triggering localized RG flows to non-trivial IR fixed points. Focusing on the case where the symmetry group O(N) is broken to a subgroup O(m) × O(N − m) on the line defect, there is an O(N) symmetric fixed point for all N, while two additional O(N) symmetry breaking ones appear for N ≥ 23. We also examine a C-theorem for localized RG flows along the sub-defect and show that the C-theorem holds in our model by perturbative calculations.