Entanglement entropy plays a variety of roles in quantum field theory, including the
connections between quantum states and gravitation through the holographic principle. This …

The many-body physics at quantum phase transitions shows a subtle interplay between
quantum and thermal fluctuations, emerging in the low-temperature limit. In this review, we …

A bstract Equilibrium finite temperature observables of a CFT can be described by a local
effective action for background fields—a “thermal effective action”. This effective action …

A bstract We describe numerous properties of the Sachdev-Ye-Kitaev model for complex
fermions with N≫ 1 flavors and a global U (1) charge. We provide a general definition of the …

We consider line defects in d-dimensional conformal field theories (CFTs). The ambient CFT
places nontrivial constraints on renormalization group (RG) flows on such line defects. We …

A bstract We study a surface defect in the free and critical O (N) vector models, defined by
adding a quadratic perturbation localized on a two-dimensional subspace of the d …

The discussions in § 2 and § 3 make it rather clear that while we have to evaluate a
sequence of functional integrals to compute the Rényi entropies, these are rather complex …

A bstract We consider line defects with large quantum numbers in conformal field theories.
First, we consider spin impurities, both for a free scalar triplet and in the Wilson-Fisher O (3) …

Abstract The critical O (N) CFT in spacetime dimensions 2< d< 4 is one of the most important
examples of a conformal field theory, with the Ising CFT at N= 1, 2⩽ d< 4, as a notable …

We use strong subadditivity of entanglement entropy, Lorentz invariance, and the Markov
property of the vacuum state of a conformal field theory to give new proof of the irreversibility …