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arXiv · 2502.00105

The entropy of radiation for local quenches in higher dimensions

Lorenzo Bianchi·Andrea Mattiello·Jacopo Sisti
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Abstract

We investigate the real time dynamics of the radiation produced by a local quench in a $d$-dimensional conformal field theory (CFT) with $d>2$. Using the interpretation of the higher-dimensional twist operator as a conformal defect, we study the time evolution of the entanglement entropy of the radiation across a spherical entangling surface. We provide an analytic estimate for the early- and late-time behavior of the entanglement entropy and derive an upper bound valid at all times. We extend our analysis to the case of a boundary CFT (BCFT) and derive similar results through a detailed discussion of the setup with two conformal defects (the boundary and the twist operator). We conclude with a holographic analysis of the process, computing the time evolution of the holographic entanglement entropy (HEE) as the area of the Ryu-Takayanagi surface in a backreacted geometry. This gives a Page-like curve in agreement with the early- and late-time results obtained with CFT methods. The extension to a holographic BCFT setup is generically hard and we consider the case of a tensionless end-of-the-world brane.

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Lorenzo Bianchi, Andrea Mattiello, Jacopo Sisti. 2025-01-31. The entropy of radiation for local quenches in higher dimensions. https://arxiv.org/abs/2502.00105

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