Dual Field Theory Research Articles

A -anomalous interactions of the holographic dilaton

We explore higher-derivative terms in the low-energy effective action for the dilaton, the Goldstone boson of spontaneously broken scale invariance. Focusing on the simplest holographic realization of spontaneously broken scale invariance, the Randall-Sundrum (RS) scenario, we identify the nonlinear action for the RS dilaton by integrating out Kaluza-Klein graviton modes. The coefficient of a particular fourth-derivative dilaton self-interaction can be identified with the Weyl $a$-anomaly of the dual conformal field theory, which we use to verify anomaly matching arguments. We also find novel, $a$-dependent couplings of the dilaton to light matter fields. These anomalous interactions can have a significant effect on the collider phenomenology and the cosmology, potentially allowing us to probe the structure of the underlying conformal sector via low-energy physics. The dilaton effective theory also serves as an interesting scalar analog of gravity, and we study solutions to the equation of motion that parallel black holes and cosmologies.

Mapping SYK to the sky

The infrared behavior of gravity in 4D asymptotically flat spacetime exhibits a rich set of symmetries. This has led to a proposed holographic duality between the gravitational mathcal{S} -matrix and a dual field theory living on the celestial sphere. Most of our current understanding of the dictionary relies on knowledge of the 4D bulk. As such, identifying intrinsic 2D models that capture the correct symmetries and soft dynamics of 4D gravity is an active area of interest. Here we propose that a 2D generalization of SYK provides an instructive toy model for the soft limit of the gravitational sector in 4D asymptotically flat spacetime. We find that the symmetries and soft dynamics of the 2D SYK model capture the salient features of the celestial theory: exhibiting chaotic dynamics, conformal invariance, and a w1+∞ symmetry. The holographic map from 2D SYK operators to the 4D bulk employs the Penrose twistor transform.

Analytical evaluation of cosmological correlation functions

Using the Schwinger-Keldysh-formalism, reformulated in [1] as an effective field theory in Euclidean anti-de Sitter, we evaluate the one-loop cosmological four-point function of a conformally coupled interacting scalar field in de Sitter. Recasting the Witten cosmological correlator as flat space Feynman integrals, we evaluate the one-loop cosmological four-point functions in de Sitter space in terms of single-valued multiple polylogarithms. From it we derive anomalous dimensions and OPE coefficients of the dual conformal field theory at space-like, future infinity. In particular, we find an interesting degeneracy in the anomalous dimensions relating operators of neighboring spins.

Phase transition structure and breaking of universal nature of central charge criticality in a Born-Infeld AdS black hole

In this paper we have considered the thermodynamics of a Born-Infeld $AdS$ black hole using inputs from the dual boundary field theory. Here, we have varied the cosmological constant $\Lambda$ and the Newton's gravitational constant $G$ along with the Born-Infeld parameter $b$ in the bulk. A novel universal critical behaviour of the central charge (occurring in the boundary conformal field theory) in extended black hole thermodynamics for charged black holes has been recently observed \cite{mann1}, and we have extended this study to Born-Infeld $AdS$ black holes. The Born-Infeld parameter has the dimension of inverse length, therefore, when considered in the first law of thermodynamics of the bulk in the mixed form which includes the central charge of the boundary conformal field theory, it modifies the thermodynamic volume and the chemical potential (which are conjugate to pressure and central charge respectively). We observe that due to this inclusion of the Born-Infeld non-linearity in this analysis, the universal nature of the critical value of the central charge observed in \cite{mann1} breaks down. We also observe an interesting behaviour of the free energy of the black hole with Hawking temperature due to the variations in both the central charge and the Born-Infeld parameter. It is also observed in our analysis that for a sufficiently small value of the Born-Infeld parameter (small value of this parameter has more prominent non-linear effects), there exists a critical value of the temperature below which no black hole can exist.

Melting of heavy vector mesons and quasinormal modes in a finite density plasma from holography

In this work, we investigate, for the first time, the melting of charmonium states within a holographic QCD model in the context of Einstein-Maxwell-dilaton theory. In the dual field theory, the model describes the heavy mesons inside a finite temperature and density medium. First, we calculate the spectrum at zero temperature. Then, at finite temperature, we obtain the spectral functions, where the heavy vector meson are represented by peaks. We show that the charmonium melts down at temperatures above the confinement/deconfinement temperature of the quark-gluon plasma. We also observe that the chemical potential speeds up the melting process. In the gravitational side of the theory, we solve the perturbation equations in the hydrodynamic limit. From this result, we read off the diffusion coefficient, then the quark number susceptibility. We show that the quark number susceptibility computed in this way does not blow up at the critical end point. We interpret this result as the lack of backreaction on the background by the action describing the vector mesons. To get the quasinormal frequencies, we solve the perturbation equations numerically. We report the emergence of a new mode whose real part increases rapidly at a certain value of the chemical potential, while its imaginary part decreases with the increasing of the chemical potential. Finally, by comparing against results obtained in the conformal plasma, we observe that the real part of the frequency increases, while the imaginary part decreases when we consider the nonconformal plasma.

A defect in AdS3/CFT2 duality

AdS3 string theory in the stringy regime k = (RAdS/ℓs)2< 1 provides a laboratory for the study of holography in which both sides of AdS/CFT duality are under fairly good control. Worldsheet string theory is solvable, and for closed strings the dual spacetime CFT is a deformation of a symmetric product orbifold. Here we extend this construction to include open strings by adding a probe D-string, described semiclassically by an AdS2 D-brane in AdS3. The dual defect or boundary conformal field theory (BCFT) is again a deformed symmetric product, which now describes the Fock space of long open and closed strings near the AdS boundary, with a boundary deformation implementing the open/closed transition in addition to the symmetric product ℤ2 twist deformation that implements closed string joining/splitting. The construction thus provides an explicit example of an AdS3/BCFT2 duality.

Integer conformal dimensions for type IIa flux vacua

We give a concise argument that supersymmetric anti--de Sitter type IIA DeWolfe-Giryavets-Kachru-Taylor flux vacua on general Calabi-Yau's have, interpreted holographically, integer conformal dimensions for low-lying scalar primaries in the dual conformal field theory. These integers are independent of any compactification details, such as the background fluxes or triple intersection numbers of the compact manifold. For the K\"ahler moduli and dilaton, there is one operator with $\mathrm{\ensuremath{\Delta}}=10$ and ${h}_{\ensuremath{-}}^{1,1}$ operators with $\mathrm{\ensuremath{\Delta}}=6$, whereas the corresponding axions have $\mathrm{\ensuremath{\Delta}}=11$ and $\mathrm{\ensuremath{\Delta}}=5$. For the complex structure moduli, the ${h}^{2,1}$ saxions have $\mathrm{\ensuremath{\Delta}}=2$, and the axions $\mathrm{\ensuremath{\Delta}}=3$. We give a tentative discussion of the origin of these integers and effects that would modify these results.

Dual theory for maximally mathcal{N} extended flat supergravity

Maximally mathcal{N} extended 2 + 1 dimensional flat supergravity theories exist for a class of super-Poincaré algebras for arbitrary mathcal{N} . They have rich asymptotic structures and contain all interesting topological supergravity solutions in presence of non-trivial holonomy. For the asymptotic symmetry algebra being a suitable flat limit of the superconformal algebra, which is an infinite dimensional extension of two copies of Osp( mathcal{N} |2; R) group, we have found the 1 + 1 dimensional chiral WZW model as the dual quantum field theory that describes the dynamics of these solutions. In the Hamiltonian analysis, the reduced phase space resembles a flat super Liouville theory.

Charged moments in W3 higher spin holography

We consider the charged moments in SL(3, ℝ) higher spin holography, as well as in the dual two-dimensional conformal field theory with W3 symmetry. For the vacuum state and a single entangling interval, we show that the W3 algebra of the conformal field theory induces an entanglement W3 algebra acting on the quantum state in the entangling interval. The algebra contains a spin 3 modular charge which commutes with the modular Hamiltonian. The reduced density matrix is characterized by the modular energy and modular charge, hence our definition of the charged moments is also with respect to these conserved quantities. We evaluate the logarithm of the charged moments perturbatively in the spin 3 modular chemical potential, by computing the corresponding connected correlation functions of the modular charge operator up to quartic order in the chemical potential. This method provides access to the charged moments without using charged twist fields. Our result matches known results for the charged moment obtained from the charged topological black hole picture in SL(3, ℝ) higher spin gravity. Since our charged moments are not Gaussian in the chemical potential any longer, we conclude that the dual W3 conformal field theories must feature breakdown of equipartition of entanglement to leading order in the large c expansion.

Gravitational quasinormal modes for Lifshitz black branes

We study the scalar and vector channels of gravitational quasinormal modes for Lifshitz black branes emerging in Einstein-Maxwell-Dilaton and Einstein-Proca theories in four and five dimensions, finding significant differences between the two models. In particular, rather surprisingly, in the Einstein-Maxwell-Dilaton model the dispersion relations for the shear and sound modes are given by ωshear ∼ −i k4 and ωsound ∼ −i k2, while in the Einstein-Proca model they take the more conventional form ωshear ∼ −i k2 and ωsound ∼ k —the proportionality constants depend on the dynamical exponent and the appropriate factors of temperature. Through the holographic duality, this calculation provides information about the relaxation of the momentum and energy flux operators in a putative dual Lifshitz field theory. Comparing with the dispersion relations obtained directly by considering Lifshitz hydrodynamics suggest that the mass density of the equilibrium state in the Einstein-Maxwell-Dilaton model is infinite.

Holographic spacetime, black holes and quantum error correcting codes: a review

This article reviews the progress in our understanding of the reconstruction of the bulk spacetime in the holographic correspondence from the dual field theory including an account of how these developments have led to the reproduction of the Page curve of the Hawking radiation from black holes. We review quantum error correction and relevant recovery maps with toy examples based on tensor networks, and discuss how it provides the desired framework for bulk reconstruction in which apparent inconsistencies with properties of the operator algebra in the dual field theory are naturally resolved. The importance of understanding the modular flow in the dual field theory has been emphasized. We discuss how the state-dependence of reconstruction of black hole microstates can be formulated in the framework of quantum error correction with inputs from extremal surfaces along with a quantification of the complexity of encoding of bulk operators. Finally, we motivate and discuss a class of tractable microstate models of black holes which can illuminate how the black hole complementarity principle can emerge operationally without encountering information paradoxes, and provide new insights into generation of desirable features of encoding into the Hawking radiation.

Emergent dual holographic description as a nonperturbative generalization of the Wilsonian renormalization group

In holographic duality, dynamics along the emergent extra-dimensional space describes a renormalization group (RG) flow of the corresponding quantum field theory (QFT). Following this idea, we develop an emergent holographic description of a QFT, where not only the information of the RG flow is introduced into an IR holographic dual effective field theory (HDEFT), but also the UV information of the QFT is encoded in the HDEFT through the IR boundary condition. In particular, we argue that this dual holographic construction is self-consistent within the assumption of bulk locality, showing the following two aspects: The solution of the Hamilton-Jacobi equation is given by the IR boundary effective action, and the Ward identity involving the QFT energy-momentum tensor current is satisfied naturally. We discuss the role of the RG $\beta$-function in the bulk effective dynamics of the metric tensor near a conformally invariant fixed point. We claim that this emergent dual gravity theory generalizes the perturbative Wilsonian RG framework into a non-perturbative way.

TsT, black holes, and Toverline{T} + Joverline{T} + Toverline{J}

We generate a class of string backgrounds by a sequence of TsT transformations of the NS1-NS5 system that we argue are holographically dual to states in a single-trace Toverline{T} + Joverline{T} + Toverline{J} -deformed CFT2. The new string backgrounds include general rotating black hole solutions with two U(1) charges as well as a smooth solution without a horizon that is interpreted as the ground state. As evidence for the correspondence we (i) derive the long string spectrum and relate it to the spectrum of the dual field theory; (ii) show that the black hole thermodynamics can be reproduced from single-trace Toverline{T} + Joverline{T} + Toverline{J} -deformed CFTs; and (iii) show that the energy of the ground state matches the energy of the vacuum in the dual theory. We also study geometric properties of these new spacetimes and find that for some choices of the parameters the three-dimensional Ricci scalar in the Einstein frame can become positive in a region outside the horizon before reaching closed timelike curves and singularities.

Chaotic dynamics of string around the conformal black hole

In this paper, we make a systematical and in-depth study on the chaotic dynamics of the string around the conformal black hole. Depending on the characteristic parameter of the conformal black hole and the initial position of the string, there are three kinds of dynamical behaviors: ordered, chaotic and being captured, chaotic but not being captured. A particular interesting observation is that there is a sharp transition in chaotic dynamics when the black hole horizon disappears, which is independent of the initial position of the string. It provides a possible way to probe the horizon structure of the massive body. We also examine the generalized MSS (Maldacena, Shenker and Stanford) inequality, which is proposed in holographic dual field theory, and find that the generalized MSS inequality holds even in the asymptotically flat black hole background. Especially, as the initial position of the string approaches the black hole horizon, the Lyapunov exponent also approaches the upper bound of the generalized MSS inequality.

Gravitational Waves at Strong Coupling from an Effective Action.

Using a holographic derivation of a quantum effective action for a scalar operator at strong coupling, we compute quasiequilibrium parameters relevant for the gravitational wave signal from a first-order phase transition in a simple dual model. We discuss how the parameters of the phase transition vary with the effective number of degrees of freedom of the dual field theory. Our model can produce an observable signal at LISA if the critical temperature is around a TeV, in a parameter region where the field theory has an approximate conformal symmetry.

Entanglement wedge in flat holography and entanglement negativity

We establish a construction for the entanglement wedge in asymptotically flat bulk geometries for subsystems in dual (1+1)-dimensional Galilean conformal field theories in the context of flat space holography. In this connection we propose a definition for the bulk entanglement wedge cross section for bipartite states of such dual non relativistic conformal field theories. Utilizing our construction for the entanglement wedge cross section we compute the entanglement negativity for such bipartite states through the generalization of an earlier proposal, in the context of the usual AdS/CFT scenario, to flat space holography. The entanglement negativity obtained from our construction exactly reproduces earlier holographic results and match with the corresponding field theory replica technique results in the large central charge limit.

Towards top-down holographic composite Higgs: minimal coset from maximal supergravity

Within the context of top-down holography, we study a one-parameter family of regular background solutions of maximal gauged supergravity in seven dimensions, dimensionally reduced on a 2-torus. The dual, four-dimensional confining field theory realises the global (spontaneous as well as explicit) symmetry breaking pattern SO(5) → SO(4). We compute the complete mass spectrum for the fluctuations of the 128 bosonic degrees of freedom of the five-dimensional gravity theory, which correspond to scalar, pseudoscalar, vector, axial-vector, and tensor bound states of the dual field theory, and includes particles with exotic SO(4) quantum numbers. We confirm the existence of tachyonic instabilities near the boundaries of the parameter space.We discuss the interplay between explicit and spontaneous symmetry breaking. The SO(5)/SO(4) coset might provide a first step towards the realisation of a calculable framework and ultraviolet completion of minimal composite Higgs models, if the four pseudo-Nambu-Goldstone bosons are identified with the real components of the Higgs doublet in the standard model (SM), and a subgroup of SO(4) with the SU(2) × U(1) SM gauge group. We exhibit an example with an additional localised boundary term that mimics the effect of a weakly-coupled external sector.

Towards a theory of bottom-up holographic models for linear Regge trajectories of light mesons

We advance in constructing a bottom-up holographic theory of linear meson Regge trajectories that generalizes and unites into one logical framework various bottom-up holographic approaches proposed in the past and scattered in the literature. The starting point of the theory is a quadratic in fields holographic five-dimensional action in which the Poincaré invariance along the holographic coordinate is violated in the most general way compatible with the linear Regge behavior of the discrete spectrum in four dimensions. It is further demonstrated how different Soft Wall (SW) like holographic models existing in the literature plus some new ones emerge from our general setup. Various interrelations between the emerging models are studied. These models include the known SW models with different sign in the exponential background, the SW models with certain generalized backgrounds, with modified metrics, and No Wall models with 5D mass depending on the holographic coordinate in a simple polynomial way. We argue that this dependence allows to describe the effects caused by the main non-local phenomena of strongly coupled 4D gauge theory, the confinement and chiral symmetry breaking, in terms of a local 5D dual field theory in the AdS space. We provide a detailed comparison of our approach with the Light Front holographic QCD, with the spectroscopic predictions of the dual Veneziano like amplitudes, and with the experimental Regge phenomenology. We apply our general approach to a holographic study of confinement, chiral symmetry breaking, and the pion form factor.

D4-branes wrapped on a spindle

We construct supersymmetric solutions of D = 6 gauged supergravity, where is a two-dimensional orbifold known as a spindle. These uplift to solutions of massive type IIA supergravity using a general prescription, that we describe. We argue that these solutions correspond to the near-horizon limit of a system of Nf D8-branes, together with N D4-branes wrapped on a spindle, embedded as a holomorphic curve inside a Calabi-Yau three-fold. The dual field theories are d = 3, mathcal{N} = 2 SCFTs that arise from a twisted compactification of the d = 5, mathcal{N} = 1 USp(2N) gauge theory. We show that the holographic free energy associated to these solutions is reproduced by extremizing an off- shell free energy, that we conjecture to arise in the large N limit of the localized partition function of the d = 5 theories on . We formulate a universal proposal for a class of off-shell free energies, whose extremization reproduces all previous results for branes wrapped on spindles, as well as on genus g Riemann surfaces Σg. We further illustrate this proposal discussing D4-branes wrapped on , for which we present a supersymmetric solution of D = 6 gauged supergravity along with the associated entropy function.

Hairy black resonators and the AdS4 superradiant instability

The superradiant instability of Kerr-AdS black holes is studied by numerically solving the full 3+1 dimensional Einstein equations. We find that the superradiant instability results in a two stage process with distinct initial and secondary instabilities. At the end of the secondary instability the geometry oscillates at several distinct fundamental frequencies -- a multi-oscillating black hole. The multi-oscillating black hole is remarkably close to a black resonator, albeit with a bit of gravitational hair. During the hairy black resonator epoch, the evolution of the horizon area is consistent with the exponential approach to a constant. By employing different seed perturbations in the initial Kerr-AdS geometry, we also demonstrate that the black resonator's hair is not unique. In the dual quantum field theory description, rotation invariance is spontaneously broken and the energy density is negative in some regions, signaling an exotic state of matter which does not relax to a stationary configuration.