A proof for string three-point functions in AdS3_3

Correlation functions of the $\text{SL}(2,\mathbb{R})$-WZW model involving spectrally flowed vertex operators are notoriously difficult to compute. An explicit integral expression for the corresponding three-point functions was recently conjectured in [arXiv:2105.12130v2]. In this paper, we provide a proof for this conjecture. For this, we extend the methods of [arXiv:2208.00978] based on the so-called $\text{SL}(2,\mathbb{R})$ series identifications, which relate vertex operators belonging to different spectral flow sectors. We also highlight the role of holomorphic covering maps in this context. Our results constitute an important milestone for proving this instance of the AdS$_3$/CFT$_2$ holographic duality at finite 't Hooft coupling.Comment: 22 page

Worldsheet computation of heavy-light correlators

We compute a large collection of string worldsheet correlators describing light probes interacting with heavy black hole microstates. The heavy states consist of NS5 branes carrying momentum and/or fundamental string charge. In the fivebrane decoupling limit, worldsheet string theory on a family of such backgrounds is given by exactly solvable null-gauged WZW models. We construct physical vertex operators in these cosets, including all massless fluctuations. We first compute a large class of novel heavy-light-light-heavy correlators in the AdS$_3$ limit, where the light operators include those dual to chiral primaries of the holographically dual CFT. We compare a subset of these correlators to the holographic CFT at the symmetric product orbifold point, and find precise agreement in all cases, including for light operators in twisted sectors of the orbifold CFT. The agreement is highly non-trivial, and includes amplitudes that describe the analogue of Hawking radiation for these microstates. We further derive a formula for worldsheet correlators consisting of $n$ light insertions on these backgrounds, and discuss which subset of these correlators are likely to be protected. As a test, we compute a heavy-light five-point function, obtaining precisely the same result both from the worldsheet and the symmetric orbifold CFT. This paper is a companion to and extension of [arXiv:2203.13828].Comment: 67 page

Black holes in string theory: Beyond supergravity.

The aim of this thesis is to demonstrate the effectiveness of worldsheet string theory in the context of black hole physics, going beyond the supergravity approximation. For a certain class of microstates, which in a particular limit admit an α′-exact description in terms of gauged Wess-Zumino-Witten (gWZW) models, we will derive consistency conditions, spectrum of massless excitations, and compute an extensive set of correlation functions. In particular, we will show how the consistency of the worldsheet conformal field theory (CFT) is in one-to-one correspondence with the absence of closed timelike curves, singularities, and horizon of the background. These conditions give rise to a set of quantisation constraints on the gauging parameters that will allow us to prove that the family of microstates we consider is the most general solution of our gWZW model. In addition, we will construct the physical states in the full gauged model and in its three-dimensional anti-de Sitter (AdS3) limit. We will also derive a formula that expresses heavy-light correlators involving an arbitrary number of massless fields in the AdS3 limit of the coset model in terms of AdS3×S3 vacuum correlator. Finally, we prove a conjecture on three-point functions in the SL(2,R) WZW model involving spectrally flowed vertex operators. These results constitute an important contribution for the understanding of black hole microstates beyond the usual supergravity approximation, and for AdS3/CFT2 holography at finite ’t Hooft coupling.<br/

A proof for string three-point functions in AdS3_3

Correlation functions of the $\text{SL}(2,\mathbb{R})$-WZW model involving spectrally flowed vertex operators are notoriously difficult to compute. An explicit integral expression for the corresponding three-point functions was recently conjectured in [arXiv:2105.12130v2]. In this paper, we provide a proof for this conjecture. For this, we extend the methods of [arXiv:2208.00978] based on the so-called $\text{SL}(2,\mathbb{R})$ series identifications, which relate vertex operators belonging to different spectral flow sectors. We also highlight the role of holomorphic covering maps in this context. Our results constitute an important milestone for proving this instance of the AdS$_3$/CFT$_2$ holographic duality at finite 't Hooft coupling

A proof for string three-point functions in AdS 3

Correlation functions of the SL(2,ℝ)-WZW model involving spectrally flowed vertex operators are notoriously difficult to compute. An explicit integral expression for the corresponding three-point functions was recently conjectured in [1]. In this paper, we provide a proof for this conjecture. For this, we extend the methods of [2] based on the so-called SL(2,ℝ) series identifications, which relate vertex operators belonging to different spectral flow sectors. We also highlight the role of holomorphic covering maps in this context. Our results constitute an important milestone for proving this instance of the AdS3/CFT2 holographic duality at finite ’t Hooft coupling.Fil: Bufalini, Davide. University of Southampton; Reino UnidoFil: Iguri, Sergio Manuel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Kovensky, Nicolas. Universite Paris-saclay (universite Paris-saclay); . Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Worldsheet Correlators in Black Hole Microstates

Light probes interacting with heavy bound states such as black holes give rise to interesting observables containing valuable dynamical information. Recently, a family of black hole microstates was shown to admit an exact string worldsheet description. We construct the physical vertex operators of these models, and derive their form in the low-energy AdS$_3$ limit. We then compute an extensive set of novel heavy-light correlators in these backgrounds. A subset of these provide the first match between worldsheet correlators in black hole microstates and the holographically dual conformal field theory, in a highly non-trivial way. We further conjecture a closed formula for heavy-light correlators with an arbitrary number of light insertions. As an application, we compute the analogue of the Hawking radiation rate for these microstates

Worldsheet Correlators in Black Hole Microstates

International audienceLight probes interacting with heavy bound states such as black holes give rise to observables containing valuable dynamical information. Recently, a family of black hole microstates was shown to admit an exact string worldsheet description. We construct the physical vertex operators of these models, and compute an extensive set of novel heavy-light correlators. We then obtain the first match between worldsheet correlators in black hole microstates and the holographically dual conformal field theory. We conjecture a closed formula for correlators with an arbitrary number of light insertions. As an application, we compute the analogue of the Hawking radiation rate for these microstates

Worldsheet computation of heavy-light correlators

We compute a large collection of string worldsheet correlators describing light probes interacting with heavy black hole microstates. The heavy states consist of NS5 branes carrying momentum and/or fundamental string charge. In the fivebrane decoupling limit, worldsheet string theory on a family of such backgrounds is given by exactly solvable null-gauged WZW models. We construct physical vertex operators in these cosets, including all massless fluctuations. We first compute a large class of novel heavy-light-light-heavy correlators in the AdS$_3$ limit, where the light operators include those dual to chiral primaries of the holographically dual CFT. We compare a subset of these correlators to the holographic CFT at the symmetric product orbifold point, and find precise agreement in all cases, including for light operators in twisted sectors of the orbifold CFT. The agreement is highly non-trivial, and includes amplitudes that describe the analogue of Hawking radiation for these microstates. We further derive a formula for worldsheet correlators consisting of $n$ light insertions on these backgrounds, and discuss which subset of these correlators are likely to be protected. As a test, we compute a heavy-light five-point function, obtaining precisely the same result both from the worldsheet and the symmetric orbifold CFT. This paper is a companion to and extension of [arXiv:2203.13828]

Black hole microstates from the worldsheet

International audienceRecently an exact worldsheet description of strings propagating in certain black hole microstate geometries was constructed in terms of null-gauged WZW models. In this paper we consider a family of such coset models, in which the currents being gauged are specified by a set of parameters that a priori take arbitrary values. We show that consistency of the spectrum of the worldsheet CFT implies a set of quantisation conditions and parity restrictions on the gauging parameters. We also derive these constraints from an independent geometrical analysis of smoothness, absence of horizons and absence of closed timelike curves. This allows us to prove that the complete set of consistent backgrounds in this class of models is precisely the general family of (NS5-decoupled) non-BPS solutions known as the JMaRT solutions, together with their various (BPS and non-BPS) limits. We clarify several aspects of these backgrounds by expressing their six-dimensional solutions explicitly in terms of five non-negative integers and a single length-scale. Finally we study non-trivial two-charge limits, and exhibit a novel set of non-BPS supergravity solutions describing bound states of NS5 branes carrying momentum charge