Search

We introduce a mixed-state generalization of the multi-entropy through the canonical purification, which we called reflected multi-entropy. We propose the holographic dual of this measure. For the tripartite case, a field-theoretical calculation is performed using a six-point function of twist operators at large $c$ limit. At both zero and finite temperature, the field-theoretical results match the holographic results exactly, supporting our holographic conjecture of this new measure., Comment: 11 pages, 11 figures

We compute the surface defect contribution to R\'{e}nyi entropy and supersymmetric R\'{e}nyi entropy in six dimensions. We first compute the surface defect contribution to R\'{e}nyi entropy for free fields, which verifies a previous formula about entanglement entropy with surface defect. Using conformal map to $S^1_\beta\times H^{d-1}$ we develop a heat kernel approach to compute the defect contribution to R\'{e}nyi entropy, which is applicable for $p$-dimensional defect in general $d$-dimensional free fields. Using the same geometry $S^1_\beta\times H^5$ with an additional background field, one can construct the supersymmetric refinement of the ordinary R\'{e}nyi entropy for six-dimensional $(2,0)$ theories. We find that the surface defect contribution to supersymmetric R\'{e}nyi entropy has a simple scaling as polynomial of R\'{e}nyi index in the large $N$ limit. We also discuss how to connect the free field results and large $N$ results., Comment: 1+14 pages, 1 figure

We consider $p$-dimensional defects in $D$-dimensional conformal field theories (CFTs) and construct defect localized entropy by performing Casini-Huerta-Myers transformation for the system with defect. The defect localized entropy is a measure of entanglement between the degrees of freedom localized on the defect. We show that at the fixed point of defect renormalization group (RG) flow, defect localized entropy is equal to minus defect free energy for universal part. We construct defect $C$-functions from the defect localized entropy for surface defects and volume defects, and show that they monotonically decrease in both cases following the entropic method by Casini and Huerta. We also study the holographic dual of defect localized entropy and find that it is given by the minimal surface located at string or brane worldvolume embedded in the holographic bulk., Comment: 11 pages, 5 figures

We study entanglement negativity for evaporating black hole based on the holographic model with defect brane. We introduce a defect extremal surface formula for entanglement negativity. Based on partial reduction, we show the equivalence between defect extremal surface formula and island formula for entanglement negativity in AdS$_3$/BCFT$_2$. Extending the study to the model of eternal black hole plus CFT bath, we find that black hole-black hole negativity decreases until vanishing, left black hole-left radiation negativity is always a constant, radiation-radiation negativity increases and then saturates at a time later than Page time. In all the time dependent cases, defect extremal surface formula agrees with island formula.

Defect extremal surface is defined by extremizing the Ryu-Takayanagi formula corrected by the quantum defect theory. This is interesting when the AdS bulk contains a defect brane (or string). We introduce a defect extremal surface formula for reflected entropy, which is a mixed state generalization of entanglement entropy measure. Based on a decomposition procedure of an AdS bulk with a brane, we demonstrate the equivalence between defect extremal surface formula and island formula for reflected entropy in AdS$_3$/BCFT$_2$. We also compute the evolution of reflected entropy in evaporating black hole model and find that defect extremal surface formula agrees with island formula., Comment: 1+35 pages, 23 figures