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arXiv:2601.16888

Universality of Dissipation across Holographic Interfaces

Andreas Karch, Mianqi Wang

Published Jan 23, 2026• 0 citations
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Abstract

Motivated by recent results in spin chains we study dissipation and relaxation in a two-dimensional \ak{holographic} interface conformal field theory (ICFT) in which degrees of freedom on one side of the interface are coupled to an external bath, while the other side remains isolated. In the bulk description this setup is realized by gluing a supersymmetric Janus geometry to a BTZ black hole region, with the coupling implemented through a double-trace deformation. We determine the quasinormal modes in the bulk by solving the double-trace matching conditions of the system and bath. Focusing on the fixed AdS$_2$ descendant channel at large frequency, we introduce the dimensionless ratio $c_{UV}$ as a projected measure of interface-induced suppression of dissipation rate. Analytically we find that in this limit, $c_{UV}$ is independent of coupling details to the bath. It is a strong candidate for a universal interface observable characterizing dissipation and relaxation across the interface, in additional to the $c_{\rm relax}$ raised in earlier work for lattice models.

DOI
10.48550/arxiv.2601.16888

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Motivated by recent results in spin chains we study dissipation and relaxation in a two-dimensional \ak{holographic} interface conformal field theory (ICFT) in which degrees of freedom on one side of the interface are coupled to an external bath, while the other side remains isolated. In the bulk description this setup is realized by gluing a supersymmetric Janus geometry to a BTZ black hole region, with the coupling implemented through a double-trace deformation. We determine the quasinormal modes in the bulk by solving the double-trace matching conditions of the system and bath. Focusing on the fixed AdS2_22​ descendant channel at large frequency, we introduce the dimensionless ratio cUVc_{UV}cUV​ as a projected measure of interface-induced suppression of dissipation rate. Analytically we find that in this limit, cUVc_{UV}cUV​ is independent of coupling details to the bath. It is a strong candidate for a universal interface observable characterizing dissipation and relaxation across the interface, in additional to the crelaxc_{\rm relax}crelax​ raised in earlier work for lattice models.
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Holographic Entanglement Entropy in Janus deformed AdS3_33​ Geometries
We investigate the time dependent entanglement entropy for boosted single intervals in interface conformal field theories (ICFT2_22​s) dual to Janus deformed AdS3_33​ geometries. For a Janus deformed Poincaré AdS3_33​ background, we obtain the entanglement entropy and a Janus induced correction using a replica technique for the equivalent dual field theory described on a conformally flat background on corresponding AdS2_22​ slices on the asymptotic boundary. The holographic entanglement entropy is then computed through certain embedding relations for the bulk Janus deformed AdS3_33​ geometry which exactly match with the field theory results. We further extend our analysis to investigate the entanglement entropy of corresponding intervals in ICFT2_22​s dual to bulk Janus deformed BTZ black hole and AdS3_33​ black string geometries obtaining consistent results from both the field theoretic and bulk computations.
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