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Amit Giveon

Publications and source records attributed to Amit Giveon.

At least 19 recordsLinked to original sources
arXiv2026

Interpolating between single and double trace $T\bar T$ by moving LST into the bulk

We describe a large class of theories that continuously interpolate between single and double trace $T\bar T$ deformations of AdS$_3$/CFT$_2$. It is obtained by starting with the spacetime $M_3$, which interpolates between AdS$_3$ in the IR and a linear dilaton spacetime in the UV, and imposing a UV cutoff on the radial direction. When the cutoff is deep in the AdS$_3$ region of $M_3$, this leads to double trace $T\bar T$. When it goes to infinity, we recover the single trace deformed theory. We present a large class of possible boundary conditions on the dilaton, and compute the resulting black hole spectrum in a few examples. In all these constructions, to leading order in the low energy expansion, the resulting spectrum is that of a single $+$ double trace deformed CFT, but at higher orders the different theories have different spectra. In one of the examples that we analyze, the full theory is single $+$ double trace $T\bar T$ deformed CFT. Another gives rise to an interesting spectrum, that consists of an infinite set of energy bands.

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arXiv2025

On String theory on deformed BTZ and $T\bar{T} + J\bar{T} + T\bar{J}$

Aspects of superstring theory on black-strings backgrounds, corresponding to deformed BTZ black holes, formed near $k$ NS5 branes by $p$ fundamental strings, and single-trace $T\bar T+J\bar T+T\bar J$ holography, are presented. It is shown that for a particular asymptotic value of the $B$-field, the excitation energy of a long string plus its contribution to the energy of the black hole is that in $T\bar T+J\bar T+T\bar J$ deformed $CFT_2$ with $c=6k$. The excitation energy of a winding $w>1$ long string plus its contribution to the background, a $w/p$ fraction of the black-hole energy, evolves according to that in a $Z_w$ twisted sector of a $p$-fold symmetric product of the latter.

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arXiv2025

On string theory on (deformed) $AdS_3\times \mathbb{T}^3$

We revisit the fermionic string theory on $AdS_3\times \mathcal{N}$ with $k=1$, and its single-trace $T\bar T$ deformation, with a focus on the $(2,2)$ superstring on (deformed) $AdS_3\times \mathbb{T}^3$. In a certain limit, it is dual to the symmetric product of the ($T\bar T$-deformed) SCFT$_2$ on $\mathbb{R}\times \mathbb{T}^3$. We present the winding-one delta-function normalizable worldsheet operators which, in the $k=1$ decoupling limit, correspond to those of $\mathbb{R}\times \mathbb{T}^3$ in spacetime. We then demonstrate how their properties in string theory reproduce those of $\mathbb{R}\times\mathbb{T}^3$, or more generally, of a ($T\bar{T}$-deformed) $\mathbb{R}\times\mathcal{N}$ seed of the boundary theory.

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arXiv2025

Effective $AdS_3/CFT_2$

In arXiv:2109.00065, it was pointed out that superstring theory on $AdS_3$ with $(NS,NS)$ $B$-field background and $R_{AdS}/l_s=\sqrt k<1$ is dual to a symmetric product CFT deformed by an operator in the $\mathbb{Z}_2$ twisted sector. We generalize the analysis of arXiv:2109.00065 to $k>1$, and show that the resulting picture matches that discussed in the bosonic case in arXiv:2110.07535. We argue that in the critical case, $k=1$ hep-th/0503121, the $\mathbb{Z}_2$ twisted deformation remains non-trivial. This resolves some confusions in the literature.

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arXiv2024

CFT Correlators from (0,2) Heterotic String

In \cite{Giveon:2024fhz}, we argued that the (0,2) heterotic string gives rise in spacetime to left and right-moving symmetric product CFT's. In this paper we confirm this claim by showing that it computes correlation functions in these CFT's.

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arXiv2024

N=2 Heterotic Strings Revisited

We show that $1+1$ dimensional vacua of the $(0,2)$ heterotic string have many properties in common with more recently studied physical systems. The free theory exhibits a symmetric product CFT structure. The single-string Hilbert space splits into sectors labeled by the string winding, $w$, that contain purely left-moving (for $w>0$) and right-moving (for $w<0$) excitations. These sectors exhibit infinite-dimensional left and right-moving symmetry algebras, respectively, with central extensions that depend on $w$. String interactions between left and right-movers appear to lead to a $T\bar T$ deformation of the free theory.

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arXiv2024

To $B$ or not to be in single-trace $T\bar T$ holography

Superstring theory on black-strings backgrounds, corresponding to deformed, rotating BTZ black holes, formed by $p$ fundamental strings or negative strings, is inspected. For non-rotating black strings, in the positive case, it was shown in [1] that the excitation energy of a probe long string, plus its contribution to the black-string background, is in harmony with single-trace $T\bar T$ holography, if the $B$-field vanishes at the origin. Here, we investigate the superstring on deformed, rotating BTZ black holes, for both the positive and negative cases, and find that for a particular value of the $B$-field, the harmony with single-trace $T\bar T$ holography persists.

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arXiv2024

Thermal partition function of $J_3 \bar{J}_3$ deformed $AdS_3$

We derive a compact formula for the one-loop, bosonic string partition function of Euclideanized $J_3 \bar J_3$ deformed $AdS_3$ with periodic Euclidean time as an integral transform of the partition function of the undeformed Euclideanized $AdS_3$. Such a deformation is interpretable as an irrelevant "single-trace $T \bar T$ deformation" of the boundary. We will do this by first establishing a formal procedure to compute a worldsheet torus zero point function for an exactly marginal $J \bar J$ deformation of a sigma model with $U(1)_L \times U(1)_R$ global symmetry. We then describe how this procedure is implemented on $SL(2,R)$ sigma model and its Euclidean continuation. Finally, we describe the embedding of the deformed $SL(2,R)$ torus amplitude into critical string theory and interpret the result as the leading perturbative contribution to the thermal partition function of the deformed theory.

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arXiv2024

On string theory on deformed BTZ and $T\bar T$

Aspects of superstring theory on deformed BTZ black holes, formed near $k$~NS5 branes by $p$~fundamental strings, and single-trace $T\bar T$ holography, are presented. The excitation energy of a singly wound long string plus its contribution to the energy of the black hole, $1/p$ fraction of the black-hole energy, is the same as that in $T\bar T$ deformed $CFT_2$ with $c=6k$. This supports the claim that the black hole can be thought of as a state in a symmetric product of $p$~$CFT_2$'s of central charge~$6k$, where the black-hole energy is split equally among all $p$ factors. A comment on superstring theory on deformed global $AdS_3$ is also presented.

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arXiv2023

Negative single-trace $T\bar T$ holography versus de Sitter holography

In single-trace $T\bar T$ holography, for the negative sign of the deformation, the geometries dual to high energy states consist of a singular UV wall that separates black strings in the IR from an asymptotically linear dilaton spacetime. In the hologram, the black strings amount to states in a symmetric product of $T\bar T$ deformed $CFT_2$, whose energy and momentum are split equally among the different blocks. The properties of this holographic duality have intriguing similarities with the proposed principles of de Sitter holography. In this note, the analogy between the two is presented. In particular, as the horizon location approaches the UV wall, one obtains a state of maximum finite entropy and infinite temperature. On the other hand, the bulk temperature of the geometry obtained in the limit is small. These properties are identical to those proposed in empty de Sitter holography.

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arXiv2023

2pf in single-trace $T\bar T$ holography

The 2pf in single-trace $T\bar T$ holography was computed and analyzed for operators in the $w=0$ sector in~\cite{Asrat:2017tzd}. Here we present its immediate generalization to non-zero winding $w$. For long strings, the result is identical to the one obtained within the TsT/$T\bar T$ approach in~\cite{Cui:2023jrb} (up to a factor of the reflection coefficient).

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arXiv2023

On the cigar CFT and Schwarzschild horizons

Aspects of shock waves and instantly-created folded strings operators in the supersymmetric $SL(2)_k/U(1)$ CFT, and their relevance to the near-horizon physics of Schwarzschild black holes in perurbative superstring theory, are presented.

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arXiv2023

Comments on Single-Trace $T\bar T$ Holography

We explore the holographic duality between string theory in backgrounds that interpolate between asymptotically linear dilaton spacetime in the UV and $AdS_3$ in the IR, and single-trace $T\bar T$ deformed CFT. In particular, we explain how the deformation of states in the boundary theory is reflected in the bulk geometry, and show that the coupling above which the deformed energy of the $SL(2,\mathbb{R})$ invariant ground state of the IR CFT becomes complex is a maximal coupling.

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arXiv2022

Asymptotically Free AdS3/CFT2

We propose a new $AdS_3/CFT_2$ duality, in which the bulk string theory has a target spacetime $AdS_3$ times a squashed three-sphere $S^3_\flat$, and the dual $CFT_2$ is a symmetric product of sigma models on $R_ϕ\times S^3_\flat$, deformed by a $ϕ$-dependent $Z_2$ twist operator. The duality maps the asymptotic region of $AdS_3$ to the region $ϕ\to\infty$, where the twist interaction in the $CFT_2$ turns off. The $AdS_3$ backgrounds in question have $R_{AdS}<\ell_s$, and so lie on the string side of the string/black hole correspondence transition. As a consequence, the high energy density of states consists of a string gas in $AdS_3$ rather than an ensemble of BTZ black holes. This property allows us to derive the dual $CFT_2$ by a systematic analysis of the worldsheet string theory on $AdS_3$.

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arXiv2021

A Puncture in the Euclidean Black Hole

We consider the backreaction of the winding condensate on the cigar background. We focus on the case of the $SL(2,\mathbb{R})_k/U(1)$ cigar associated with, e.g., the near-horizon limit of $k$ NS5 black-branes. We solve the equations of motion numerically in the large $k$ limit as a function of the amplitude, $A$, of the winding mode at infinity. We find that there is a critical amplitude, $A_c=\exp(-\gamma/2)$, that admits a critical solution. In string theory, the exact $SL(2,\mathbb{R})_k/U(1)$ cigar CFT fixes completely the winding amplitude, $A_s$, at infinity. We find that in the large $k$ limit there is an exact agreement, $A_c=A_s$. The critical solution is a cigar with a puncture at its tip; consequently, the black-hole entropy is carried entirely by the winding condensate. We argue that, in the Lorentzian case, the information escapes the black hole through this puncture.

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arXiv2021

Explicit microstates at the Schwarzschild horizon

The claim that the microstates of Schwarzschild black holes in perturbative string theory amount to the modes of long folded strings in the vicinity of its horizon is supported by more evidence.

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arXiv2020

Comments on D3-Brane Holography

We revisit the idea that the quantum dynamics of open strings ending on $N$ D3-branes in the large $N$ limit can be described at large `t Hooft coupling by classical closed string theory in the background created by the D3-branes in asymptotically flat spacetime. We study the resulting thermodynamics and compute the Hagedorn temperature and other properties of the D3-brane worldvolume theory in this regime. We also consider the theory in which the D3-branes are replaced by negative branes and show that its thermodynamics is well behaved. We comment on the idea that this theory can be thought of as an irrelevant deformation of $\mathcal{N}=4$ SYM, and on its relation to $T\bar T$ deformed $CFT_2$.

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