Flavors of entanglement

Abstract

We employ holography to investigate Liu-Mezei renormalization group monotones in conformal field theories influenced by massive flavor degrees of freedom. We examine the entanglement entropy of a spherical subregion in three holographic field theories — N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 Klebanov-Witten theory, N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 4 SYM theory, and ABJM theory — with fundamental flavor. The gravity dual of massive unquenched flavor is described by dynamical D-branes, and we solve their backreaction in the smeared approximation. We compute entanglement entropy using the Ryu-Takayanagi formula in these backreacted geometries. Our findings indicate that the Liu-Mezei A- and F-functions decrease monotonically to leading order in the number of flavors across all examples. Additionally, we calculate the leading flavor contribution to entanglement entropy using an alternative probe brane method that does not require knowledge of backreaction in the bulk geometries. These results consistently match with backreacted calculations in all cases, assuming omission of a specific IR boundary term stemming from a total derivative.