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Tommaso Canneti

Publications and source records attributed to Tommaso Canneti.

10 recordsLinked to original sources
arXiv2026

Flux tube profile from Holography: finite size and strong coupling corrections

We use the holographic correspondence as a tool to study the classical flux tube profile connecting a static quark-antiquark pair in a $2+1$-dimensional strongly-coupled large $N$ QCD-like theory. The final result extends already known findings in the literature in several ways. First, it is an analytical function of both the space-like boundary coordinates; in other words, we keep track of what happens both along and transversely to the inter-quark axis. Then, we take into account the finiteness of the inter-quark distance and the first correction in the strong coupling expansion. To the same order, we also confirm the relation between the mass of the lightest glueball in the spectrum and the intrinsic width of the flux tube profile. We conclude by trying to gain some insights about the quantum fluctuations. Intriguingly, our proposal is in agreement with widespread expectations in the literature. En passant, we also derive a semi-analytical formula that gives the first correction to the scalar glueball masses in the strong coupling expansion.

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arXiv2026

Hagedorn temperature from holography: rotating and charged systems

Using the string/field theory correspondence as a tool, we study the dependence of the Hagedorn temperature of strongly coupled, planar gauge theories on angular velocities and chemical potentials for $U(1)$ global currents. Our results are obtained from an interplay of world-sheet semiclassical quantization methods and target space low energy effective ones. The Hagedorn temperature is given as an expansion in the inverse (large) 't Hooft coupling limit. Working to quadratic order in the fluctuations, the world-sheet analysis provides the leading, the next-to-leading and part of the next-to-next-to leading order terms. In particular, it captures the NNLO $\log 2$ terms which are due to the contributions of non-zero modes to the zero-point energy. These modes are not accounted for by the effective approach, within which they have to be included by hand using suitable educated guesses. On the other hand, the effective methods allow to compute in a relatively easy way the missing NNLO pieces (and even further subleading corrections), which could be accounted for from the world-sheet approach only working at quartic (or higher) order in the fluctuations. We present general results and several examples in various dimensions, including both confining models and conformal field theories on spheres (such as $\mathcal N=4$ SYM and ABJM) dual to string theories on global $AdS$ spaces.

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arXiv2025

Vacuum configuration of winding superstrings from non-standard semiclassical quantization

Semiclassical quantization techniques are unreliable, if the magnitude of the quantum fluctuations becomes comparable with a classical background scale. This is the case, for example, for superstrings at temperatures close to the Hagedorn temperature. Here, we propose a non-standard treatment which aims to extend the semiclassical approach for type-II superstrings to such cases. This allows us to provide a well-posed reformulation of recent computations of the Hagedorn temperature in a large class of confining gauge theories. Along the way, we fill a gap in the literature by proving that the standard semiclassical one-loop partition function of the Green-Schwarz superstring can be made finite, by means of a suitable choice of integration measures, for any background worldsheet in a target spacetime satisfying the (type-IIA) supergravity field equations.

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arXiv2025

Holographic Hagedorn Temperature: Strong Coupling, Flavor and $θ$-angle Effects

We study the Hagedorn temperature $T_H$ of strongly coupled quantum field theories admitting a holographic string or M-theory description in various regimes and scenarios. In the first part of the paper we propose a ``thermal scalar'' effective approach to the calculation of $T_H$ in eleven-dimensional supergravity. The proposal allows to extend the existing results for $T_H$ to the strongly coupled string regime, i.e. to a previously unexplored regime of field theory parameters where the number of colors $N$ is smaller than (some power of) the 't Hooft coupling $λ$. We can thus extend the existing results for the $α'$ expansion of the ABJM model, which have a spectacular agreement with predictions from integrability, in a different direction in parameter space. In particular, we explicitate the first non-perturbative corrections. We also apply the formalism to the Witten-Yang-Mills model, finding that the result for the ratio of $T_H$ with the deconfinement temperature is in the same ballpark of the lattice one for pure Yang-Mills. Within the same model, we study the dependence of the Hagedorn temperature on the $θ$-angle. In the second part of the paper we analyze the effect of dynamical flavors on $T_H$ in confining theories. By studying the few available examples of regular backgrounds dual to confining theories with flavors, we find that generally the effects of flavors is to reduce the value of $T_H$ in units of the square root of the confining string tension. The effect turns out to be milder than the analogous reduction of the critical temperature for deconfinement when the latter is known.

hep-th↗
arXiv2025

Hagedorn temperature in holography: world-sheet and effective approaches

We provide general results on the Hagedorn temperature of planar, strongly coupled confining gauge theories holographically dual to type II superstring models on curved backgrounds with Ramond-Ramond and Kalb-Ramond fluxes and non-trivial dilaton. For exact backgrounds the Hagedorn temperature is determined up to next-to-next-to-next-to-leading order (NNNLO) in an expansion in $α'$; in all the other cases the results can be safely trusted up to NNLO. To reach these goals we exploit two complementary approaches. On the one hand, we perform an extrapolation to the Hagedorn regime of world-sheet results obtained from the semiclassical quantization of string configurations winding around the compact Euclidean time direction. En passant, we provide a detailed derivation of the fermionic part of the world-sheet spectrum, which is hard to find in the literature. On the other hand, we perturbatively solve the equations of motion for the thermal scalar field corresponding to the lightest mode of the winding string, which in flat space becomes tachyonic above the Hagedorn temperature. The interplay between different approaches is surely convenient, but we provide insights about a possible derivation of the whole NNLO correction to the Hagedorn temperature from a pure world-sheet perspective; furthermore, we determine the effective mass of the thermal scalar from the world-sheet in full generality.

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arXiv2025

Higher Order Corrections to the Hagedorn Temperature at Strong Coupling

We propose a general formula for higher order corrections to the value of the Hagedorn temperature of a class of holographic confining gauge theories in the strong coupling expansion. Inspired by recent proposals in the literature, the formula combines the sigma-model string expansion with an effective approach. In particular, it includes the sigma-model contributions to the Hagedorn temperature at next-to-next-to leading order, which are computed in full generality. For ${\cal N}=4$ SYM on $S^3$ our result agrees with numerical field theory estimates with excellent precision. We use the general formula to predict the value of the Hagedorn temperature for ABJM on $S^2$ and for the dual of purely RR global $AdS_3$.

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arXiv2023

Semiclassical Quantization of the Superstring and Hagedorn Temperature

In a recent paper [1], the semiclassical quantization of a string, winding once around the compact Euclidean time circle, on a supergravity background dual to the deep infrared regime of a confining finite temperature gauge theory, was carried out. The string mass-shell condition and, by extrapolation, the Hagedorn temperature to leading order in the holographic limit was deduced. In this work, we improve on those results in three ways. First, we fix some missing details of the related light-cone quantization analysis. Second, we reconsider the problem under the lens of a background-covariant geometrical formalism. This allows us to put the semiclassical mass-shell condition on more solid grounds. Finally, going beyond the semiclassical regime, we compute the Hagedorn temperature at next-to-leading order in the holographic limit. The sub-leading correction turns out to arise entirely from the contribution of the zero modes of the massive worldsheet scalar fields. Our result matches that of a recent analysis in the literature based on the Horowitz-Polchinski stringy star effective model.

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arXiv2023

On the Hagedorn Temperature in Holographic Confining Gauge Theories

The divergence of the string partition function due to the exponential growth of states is a well-understood issue in flat spacetime. It can be interpreted as the appearance of tachyon modes above a certain temperature, known as the Hagedorn temperature $T_H$. In the literature, one can find some intuitions about its generalization to curved spacetimes, where computations are extremely hard and explicit results cannot be provided in general. In this paper, we present a genus-zero estimate of $T_H$, at leading order in $α'$, for string theories on curved backgrounds holographically dual to confining gauge theories. This is a particularly interesting case, since the holographic correspondence equates $T_H$ with the Hagedorn temperature of the dual gauge theories. For concreteness we focus on Type IIA string theory on a well known background dual to an $SU(N)$ Yang-Mills theory. The resulting Hagedorn temperature turns out to be proportional to the square root of the Yang-Mills confining string tension. The related coefficient, which at leading order is analytically determined, is the same as the one for Type II theories in flat space. While the calculation is performed in a specific model, the result applies in full generality to confining gauge theories with a top-down holographic dual.

hep-th↗
arXiv2021

Bubble Wall Velocity at Strong Coupling

Using the holographic correspondence as a tool, we determine the steady-state velocity of expanding vacuum bubbles nucleated within chiral finite temperature first-order phase transitions occurring in strongly-coupled large $N$ QCD-like models. We provide general formulae for the friction force exerted by the plasma on the bubbles and for the steady-state velocity. In the top-down holographic description, the phase transitions are related to changes in the embedding of $Dq$-${\bar Dq}$ flavor branes probing the black hole background sourced by a stack of $N$ $Dp$-branes. We first consider the Witten-Sakai-Sugimoto $D4$-$D8$-$\bar D8$ setup, compute the friction force and deduce the equilibrium velocity. Then we extend our analysis to more general setups and to different dimensions. Finally, we briefly compare our results, obtained within a fully non-perturbative framework, to other estimates of the bubble velocity in the literature.

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