The holographic complexity conjectures are considered in a Einstein-Maxwell-Dilaton gravity, by using the "Complexity-Volume" proposal. Specifically, we calculate the growth rate of complexity for an eternal charged AdS-dilaton black holes with fixed and dynamical boundaries respectively. The dynamical boundary is achieved by introducing a moving self-graviting brane on which the induced metric has an exact FLRW form. In case of fixed AdS boundary, there exists a bound for evolution of growth rate on late time, while this bound will become larger as the dilaton coupling constant $α$ increases. In large $α$ limit, we analytically prove that this bound is a finite value which is proportional to the black hole mass. In case of dynamical boundary, namely the brane-bulk system, the growth rate decreases monotonously on late time, after reaching a maximum value at a certain time. We find that the evolution of growth rate for brane-bulk system on late time is dominated by the velocity of the moving brane. We guess this result is model-independent.
The number of asymptotically de Sitter (non-singular) solutions of 5d dilatonic gravity with positive cosmological constant is found. These solutions are similar to the previously known asymptotically AdS spaces where dilaton may generate the singularity. Using these solutions the consistent $c$-function is proposed in the same way as in AdS/CFT. The consistency of RG flow gives further support for dS/CFT correspondence. From holographic RG flow equations we calculate the holographic 4d conformal anomaly with dilatonic contributions. This conformal anomaly turns out to be the same as in AdS/CF…
The equivalence between the holographic renormalization group and the soft dilaton theorem is shown for a class of wrapped metrics solutions of the string beta function equations for the bosonic string.
We propose an holographic $k$-essence and dilaton models of dark energy. The correspondence between the $k$-essence and dilaton energy densities with the holographic density, allows the reconstruction of the potential and the fields for the $k$-essence and dilaton models in flat FRW background. For the proposed infrared cut-off the reconstruction was made for the two cases of the constant $α$: for $α<1$ the model presents phantom crossing and the reconstruction was made in the region before the $ω=-1$ crossing for the EoS parameter. The cosmological dynamics for $α>1$ was also reconstructed. T…
We derive an explicit form of the dilaton potential in improved holographic QCD (IHQCD) from the QCD lattice data of the chiral condensate as a function of the quark mass. This establishes a data-driven holographic modeling of QCD -- machine learning holographic QCD. The modeling consists of two steps for solving inverse problems. The first inverse problem is to find the emergent bulk geometry consistent with the lattice QCD simulation data at the boundary. We solve this problem with the refinement of neural ordinary differential equation, a machine learning technique. The second inverse probl…
We study certain features of a strongly coupled theory whose gravitational dual is given by two-charge dilatonic black hole in AdS5 which has recently been used to study holographic Fermi liquids. By making use of the gravity description, we have studied conductivity, holographic entanglement entropy and dynamics of a charged scalar field. In particular at low energy we find that the temperature dependence of the real part of the conductivity goes as T^3 and the background is stable against scalar condensations.
Stability of dilatonic AdS spaces due to quantum effects of dilaton coupled conformal matter is considered. When such spaces do not exist on classical level, their dynamical generation occurs. Explicit examples corresponding to quantum creation of d4 dilatonic AdS Universe and of d2 dilatonic AdS Black Hole (BH) are presented. Motivated by holographic RG, in the similar approach the complete d5 effective action is discussed. The intermediate region where it is the sum of two parts: bulk (classical gravity) and boundary quantum action is investigated. The effective equations solution representi…
By imposing the relativistic boundary term and Lorentz violating that in the dilatonic black brane with a Lifshitz like IR geometry and $AdS_4$ boundary, we study the properties of the spectral functions of the fermions. We find that in the two fixed points, there are emergent Fermi-surface structures and many properties seem to be in agreement with that of Fermi liquid. Especially, the low energy behavior exhibits a linear dispersion relation. In addition, we also find that a holographic flat band also emerges in this background of the dilatonic black brane.
Recent progress in the holographic approach makes it more transparent that each conductivity can be decomposed into the coherent contribution due to momentum relaxation and the incoherent contribution due to intrinsic current relaxation. In this paper we investigate this decomposition in the framework of Einstein-Maxwell-dilaton theory. We derive the perturbation equations, which are decoupled for a large class of background solutions, and then obtain the analytic results of conductivity with the slow momentum relaxation in low frequency approximation, which is consistent with the known result…
We investigate the vacuum instability in the presence of dilaton field in a holographic set up. Although the dilaton is a bulk field, it leads to the vacuum instability on the boundary. We show that the whole process crucially depends on the probe brane position and as well on the radial coordinate. So that the effects of dilaton scale parameter in different regions of the bulk or for different probe brane positions are different. We also observe that in our study the temperature can strengthen the effect of scale parameter in reducing the potential barrier. Finally, we show that this Schwinge…
In this paper, we first study the Lifshitz-dilaton holographic superconductors with nonlinear Born-Infeld (BI) gauge field and obtain the critical temperature of the system for different values of Lifshitz dynamical exponent, $z$, and nonlinear parameter $b$. We find that for fixed value of $b$, the critical temperature decreases with increasing $z$. This indicates that the increase of anisotropy between space and time prevents the phase transition. Also, for fixed value of $z$, the critical temperature decrease with increasing $b$. Then, we investigate the optical properties of ($2+1$) and ($…
We discuss dilatonic gravity (bulk theory) from the point of view of (generalized) AdS/CFT correspondence. Self-consistent dilatonic background is considered. It may be understood as two boundaries space where AdS boundary appears as infinite boundary and new (singular) boundary occurs at short distances. The two-point correlation function and conformal dimension for minimal and dilaton coupled scalar are found. Even for minimal scalar, the conformal dimension is found to be different on above two boundaries. Hence, new CFT appears in AdS/CFT correspondence at short distances. AdS/CFT correspo…
We derive a class of charged rotating dilaton black string solutions in the background of anti-de-Sitter spaces with an appropriate combination of three Liouville-type dilaton potentials. We also present the suitable counterterm which removes the divergences of the action in the presence of dilaton potential. The solutions are analyzed and their thermodynamics is discussed by using the counterterm method.
Trace anomaly for dilaton coupled conformal theories on curved background with non-zero dilaton is found from supergravity side as an IR effect using AdS/CFT correspondence. For $d=2$ it coincides with the conformal anomaly for dilaton coupled scalar (up to total derivative term which is known to be ambiguous). In four-dimensional case we get conformal anomaly for ${\cal N}=4$ super YM theory interacting with conformal supergravity. In the same way the calculation of dilaton dependent conformal anomaly in higher dimensions seems to be much easier than using standard QFT methods.
In this proceedings contribution we summarize and discuss results of Refs. \cite{Grumiller:2013swa, Grumiller:2015vaa} in the light of recent developments in $\textrm{AdS}_2$ holography \cite{Maldacena:2016upp, Jensen:2016pah, Engelsoy:2016xyb}.
A variational principle is constructed for gravity coupled to an asymptotically linear dilaton and a p-form field strength. This requires the introduction of appropriate surface terms -- also known as `boundary counterterms' -- in the action. The variation of the action with respect to the boundary metric yields a boundary stress tensor, which is used to construct conserved charges that generate the asymptotic symmetries of the theory. In most cases a minimal set of assumptions leads to a unique set of counterterms. However, for certain examples we find families of actions that depend on one o…
We study thermodynamic instability of a class of $(n+1)$-dimensional charged dilaton black holes in the background of anti-de Sitter universe. We calculate the quasilocal mass of the AdS dilaton black hole through the use of the subtraction method of Brown and York. We find a Smarr-type formula and perform a stability analysis in the canonical ensemble and disclose the effect of the dilaton field on the thermal stability of the solutions. Our study shows that the solutions are thermally stable for small $α$, while for large $α$ the system has an unstable phase, where $α$ is a coupling constant…
We study glueballs in the holographic gauge theories, supersymmetric and non-super symmetric cases, which are given by the type IIB superstring solutions with non-trivial dilaton. In both cases, the dilaton reflects the condensate of the gauge field strength, $<F^2>$, which is responsible to the linear confining potential between the quark and anti-quark. Then we could see the meson spectra. On the other hand, the glueball spectra are not found in the supersymmetric case. We need a sharp wall, which corresponds to an infrared cutoff, in order to obtain the glueballs. In the non-supersymmetric …
Within a holographic framework, we consider vector mesons riding on a gravity-dilaton background. The latter one is determined directly from a Schrödinger equivalent potential which delivers a proper $ρ$ meson Regge trajectory. The mapping on the dilaton potential yields a thermodynamic phase structure with a first-order transition.
We investigate the phase structure of a charged AdS dilaton black hole in the extended phase space which takes the cosmological constant, i.e. the AdS-$Λ$ parameter as pressures. Through both thermal ensemble and quasinormal mode analysis, we find that stable phase of the black hole with non-trivial dilaton profiles always exists for both large and small couplings when the AdS-$Λ$ is considered dynamical degrees of freedom. This forms a somewhat contrast with previous works which does not do so. Our results provide new examples for the parallelism or equivalences between thermal ensemble metho…
A recent study shows that Hawking radiation of the massless scalar field does not appear on the two-dimensional AdS$_2$ black hole background. We study this issue by investigating absorption and reflection coefficients under dilaton coupling with the matter field. If the scalar field does not couple to the dilaton, then it is fully absorbed into the black hole without any outgoing mode. On the other hand, once it couples to the dilaton field, the outgoing mode of the massless scalar field exists and the nontrivial Hawking radiation is obtained. Finally, we comment on this dilaton dependence of…
A 5D black hole(M$_5$) is investigated in the type IIB superstring theory compactified on S$^1 \times $T$^4$. This corresponds to AdS$_3 \times $S$^3 \times $T$^4$ in the near horizon with asymptotically flat space. Here the harmonic gauge is introduced to decouple the mixing between the dilaton and others. On the other hand we obtain the BTZ balck hole(AdS$_3\times$S$^3\times$T$^4$) as the non-dilatonic solution. We calculate the greybody factor of the dilaton as a test scalar both for a 5D black hole(M$_5 \times $S$^1 \times $T$^4$) and the BTZ black hole(AdS$_3 \times $S$^3 \times $T$^4$). …
We study a realization of light dilatons by considering Conformal Field Theories deformed by a nearly marginal operator ${\cal O}$. This is discussed in the holographic setup consisting of Renormalization Group flows that end on a soft wall. We obtain a mass formula for the dilaton as an average along the flow. Finally we discuss the holographic method to compute the condensate $\langle {\cal O} \rangle$.
We study a bi-parametric family of dilaton gravity models with constant and negative curvature. This family includes the Jackiw-Teitelboim gravity and the Liouville gravity model induced by a bosonic string. Furthermore, this family is conformally equivalent to the hiperbolic dilaton models. We propose boundary conditions in the Fefferman-Graham and in the Eddington-Finkelstein gauge. We check the consistency of the asymptotic conditions by computing the entropy of their black hole solution.
In the background of a charged AdS dilaton black hole, we investigate the movement of a self-graviting 3-brane and relevant holographic effects as the brane move close to the AdS boundary. The induced metric on brane corresponds to an exact FLRW geometry, while the evolution of brane is determined by Israel junction condition and the effective Einstein field equation on brane together. When the brane approaches the AdS boundary, AdS/CFT correspondence implies that a radiation dominated FLRW-universe ($P=\frac{1}{3}ρ$) should be given. According to the holographic renormalization procedure, we …
d5 dilatonic gravity action with surface counterterms motivated by AdS/CFT correspondence and with contributions of brane quantum CFTs is considered around AdS-like bulk. The effective equations of motion are constructed. They admit two (outer and inner) or multi-brane solutions where brane CFTs may be different. The role of quantum brane CFT is in inducing of complicated brane dilatonic gravity. For exponential bulk potentials the number of AdS-like bulk spaces is found in analytical form. The correspondent flat or curved (de Sitter or hyperbolic) dilatonic two branes are created, as a rule, …
We study dilaton-gravity theories in 2-dimensions obtained by dimensional reduction of higher dimensional nonrelativistic theories. Focussing on certain families of extremal charged hyperscaling violating Lifshitz black branes in Einstein-Maxwell-scalar theories with an extra gauge field in 4-dimensions, we obtain $AdS_2$ backgrounds in the near horizon throats. We argue that these backgrounds can be obtained in equivalent theories of 2-dim dilaton-gravity with an extra scalar, descending from the higher dimensional scalar, and an interaction potential with the dilaton. A simple subcase here i…
We present the metric for the $(n+1)$-dimensional charged rotating dilaton black branes with cylindrical or toroidal horizons in the background of anti-de Sitter spacetime. We find the suitable counterterm which removes the divergences of the action in the presence of the dilaton potential in all higher dimensions. We plot the Penrose diagrams of the spacetime and reveal that the spacetime geometry crucially modifies in the presence of the dilaton field. The conserved and thermodynamic quantities of the black branes are also computed.
We construct the holographic dictionary for both running and constant dilaton solutions of the 2D Einstein-Maxwell-Dilaton theory obtained by a circle reduction from 3D gravity with negative cosmological constant. This specific model ensures that the dual theory has a well defined ultraviolet completion in terms of a 2D CFT, but our results apply qualitatively to a wider class of 2D dilaton gravity theories. For each type of solutions we perform holographic renormalization, compute the exact renormalized one-point functions in the presence of arbitrary sources, and derive the asymptotic symmet…
We disclose the effects of the logarithmic nonlinear electrodynamics on the holographic conductivity of Lifshitz dilaton black holes/branes. We analyze thermodynamics of these solutions as a necessary requirement for applying gauge/gravity duality, by calculating conserved and thermodynamic quantities such as the temperature, entropy, electric potential and mass of the black holes/branes. We calculate the holographic conductivity for a $(2+1)$-dimensional brane boundary and study its behavior in terms of the frequency per temperature. Interestingly enough, we find out that, in contrast to the …
We construct holographic superconductors from Einstein-Maxwell-dilaton gravity in 3+1 dimensions with two adjustable couplings $α$ and the charge $q$ carried by the scalar field. For the values of $α$ and $q$ we consider, there is always a critical temperature at which a second order phase transition occurs between a hairy black hole and the AdS RN black hole in the canonical ensemble, which can be identified with the superconducting phase transition of the dual field theory. We calculate the electric conductivity of the dual superconductor and find that for the values of $α$ and $q$ where $α/…
Driven by the landscape of garden-variety condensed matter systems, we have investigated how the dual spectral function behaves at the non-relativistic as well as relativistic fermionic fixed point by considering the probe Dirac fermion in an extremal charged dilatonic black hole with zero entropy. Although the pattern for both of the appearance of flat band and emergence of Fermi surface is qualitatively similar to that given by the probe fermion in the extremal Reissner-Nordstrom AdS black hole, we find a distinctly different low energy behavior around the Fermi surface, which can be traced …
Bosonic sector of d5 gauged supergravity with specific parametrization of full scalar coset is considered (multi-dilaton gravity). Using holographic RG in the form suggested by de Boer-Verlinde-Verlinde the holographic d4 conformal anomaly (in the sector of curvature invariants) is found when bulk potential is not constant. Its comparison with the earlier calculation done in the scheme where expansion of metric and dilaton over radial coordinate of AdS space is used demonstrates scheme dependence of holographic conformal anomaly. In AdS/CFT correspondence where dilatons play role of coupling c…
We calculate the pressure, entropy density, trace anomaly and speed of sound of the gluon plasma using the dilaton potential of Ref. arXiv:0911.0627[hep-ph] in the dilaton-gravity theory of AdS/QCD. The finite temperature observables are calculated from the Black Hole solutions of the Einstein equations, and using the Bekenstein-Hawking equality of the entropy with the area of the horizon. Renormalization is well defined, because the T=0 theory has asymptotic freedom. Comparison with lattice simulations is made.
We present a dilatonic description of the holographic dark energy by connecting the holographic dark energy density with the dilaton scalar field energy density in a flat Friedmann-Robertson-Walker universe. We show that this model can describe the observed accelerated expansion of our universe with the choice $c\geq1$ and reconstruct the kinetic term as well as the dynamics of the dilaton scalar field.
We perform a holographic renormalization of gravity duals to little string theories. In particular, we construct counterterms which yield a well-defined type II action for NS-sector linear dilaton backgrounds. Our methods are based on a similar recent construction in asymptotically flat spacetimes, and our work demonstrates in detail the parallels between asymptotically flat and linear dilaton boundary conditions. The counterterms guarantee that (i) the on-shell action is finite and (ii) asymptotically linear dilaton solutions are stationary points of the action under all boundary condition pr…
A holographic model of probe quarkonia is presented, where the dynamical gravity-dilaton background is adjusted to the thermodynamics of 2 +1 flavor QCD with physical quark masses. The quarkonia action is modified to account for a systematic study of the heavy-quark mass dependence. We focus on the $J/ψ$ and $Υ$ spectral functions and relate our model to heavy quarkonia formation as a special aspect of hadron phenomenology in heavy-ion collisions at LHC.
We consider a very general dilaton-axion system coupled to Einstein-Hilbert gravity in arbitrary dimension and we carry out holographic renormalization for any dimension up to and including five dimensions. This is achieved by developing a new systematic algorithm for iteratively solving the radial Hamilton-Jacobi equation in a derivative expansion. The boundary term derived is valid not only for asymptotically AdS backgrounds, but also for more general asymptotics, including non-conformal branes and Improved Holographic QCD. In the second half of the paper, we apply the general result to Impr…
AdS/CFT induced quantum dilatonic brane-world where 4d boundary is flat or de Sitter (inflationary) or Anti-de Sitter brane is considered. The classical brane tension is fixed but boundary QFT produces the effective brane tension via the account of corresponding conformal anomaly induced effective action. This results in inducing of brane-worlds in accordance with AdS/CFT set-up as warped compactification. The explicit, independent construction of quantum induced dilatonic brane-worlds in two frames: string and Einstein one is done. It is demonstrated their complete equivalency for all quantum…
Motivated by the recently proposed Kerr/CFT correspondence, we investigate the holographic dual of the extremal and non-extremal rotating linear dilaton black hole in Einstein-Maxwell-Dilaton-Axion Gravity. For the case of extremal black hole, by imposing the appropriate boundary condition at spatial infinity of the near horizon extremal geometry, the Virasoro algebra of conserved charges associated with the asymptotic symmetry group is obtained. It is shown that the microscopic entropy of the dual conformal field given by Cardy formula exactly agrees with Bekenstein-Hawking entropy of extrema…
In this paper we consider the holographic DC and Hall conductivity in Einstein-Maxwell-Dilaton in Gauss-Bonnet gravity with momentum dissipation. We analytically derived the DC conductivity and Hall conductivity from the black horizon data, and found that the conductivities are independent on the Gauss-Bonnet coupling. We also used the entropy function formalism to get the conductivities in terms of the charge of the black hole, even without knowing the explicit black hole solutions.
We investigate the holographic DC and Hall conductivity in massive Einstein-Maxwell-Dilaton (EMD) gravity. Two special EMD backgrounds are considered explicitly. One is dyonic Reissner-Nordstr$\ddot{o}$m-AdS (RN-AdS) geometry and the other one is hyperscaling violation AdS (HV-AdS) geometry. We find that the linear-T resistivity and quadratic-T inverse Hall angle can be simultaneously achieved in HV-AdS models, providing a hint to construct holographic models confronting with the experimental data of strange metal in future.
A holographic model of probe vector mesons (quarkonia) is presented, where the dynamical gravity-dilaton background is adjusted to the thermodynamics of 2 +1 flavor QCD with physical quark masses. The vector meson action is modified to account for various quark masses. We focus on the $Φ$, $J/ψ$ and $Υ$ meson melting in agreement with hadron phenomenology in heavy-ion collisions at LHC, that is the formation of hadrons at the observed freeze-out temperature of 155 MeV.
We investigate N-point string scattering amplitudes in AdS_3 space. Based on recent observations on the solutions of KZ and BPZ-type differential equations, we discuss how to describe the string theory in AdS_3 as a marginal deformation of a (flat) linear dilaton background. This representation resembles the called "discrete light-cone Liouville" realization as well as the FZZ dual description in terms of the sine-Liouville field theory. Consequently, the connection and differences between those and this realization are discussed. The free field representation presented here permits to underst…
We derive an explicit form of the dilaton potential in improved holographic QCD (IHQCD) from the experimental data of the $ρ$ meson spectrum. For this purpose we make use of the emergent bulk geometry obtained by deep learning from the hadronic data in arXiv:2005.02636. Requiring that the geometry is a solution of an IHQCD derives the corresponding dilaton potential backwards. This determines the bulk action in a data-driven way, which enables us at the same time to ensure that the deep learning proposal is a consistent gravity. Furthermore, we find that the resulting potential satisfies the r…
We show that string theory in AdS3 has two distinct phases depending on the radius of curvature R_{AdS}=\sqrt{k}l_s. For k>1 (i.e. R_{AdS}>l_s), the SL(2,C) invariant vacuum of the spacetime conformal field theory is normalizable, the high energy density of states is given by the Cardy formula with c_{eff}=c, and generic high energy states look like large BTZ black holes. For k<1, the SL(2,C) invariant vacuum as well as BTZ black holes are non-normalizable, c_{eff}<c, and high energy states correspond to long strings that extend to the boundary of AdS3 and become more and more weakly coupled t…
We report a dynamical formation of a (Mott) gap from holographic fermions. By coupling a fermion field with dipole action to the charged dilaton black branes with a Lifshitz like IR geometry and $AdS_{4}$ boundary, we find that when the dipole interaction is large enough, spectral weight is transferred between bands, and beyond a critical dipole interaction, a gap emerges in the fermion density of states. The value of the gap becomes larger as the strength of the interaction keeps increasing.
We study a set of examples of holographic duals to theories with spontaneous breaking of conformal invariance in different dimensions. The geometries are domain walls interpolating between two AdS spaces, with a non-trivial background scalar field dual to a relevant operator. We comment on a subtlety in the low momentum expansion pointed out in arXiv:1304.3051 for the case of background gravity and revise the dynamical gravity results of arXiv:1207.0006, where the dilaton pole was missing in the scalar-scalar and tensor-tensor two-point functions. We compute the energy-momentum tensor and scal…
A modified version of the usual soft wall quadratic dilaton, a dilaton which catches the variation of the proton mass inside nucleons in the nuclear medium is used. With this dilaton, called nuclear dilaton, we have calculated the electromagnetic form factors and magnetic moments associated with the in-medium proton following the AdS/QCD prescription.
Holographic Renormalization Group (RG) in nine dimensions is considered. The d8 holographic conformal anomaly is found. It should correspond to d8 CFT in AdS_9/CFT_8 correspondence. The comparison of holographic and QFT anomalies in d8 de Sitter space is done. It may give the indication for rigorous AdS_9/CFT_8 correspondence proposal.
We look into the $AdS$ black holes from two-dimensional gravity perspective. In this work, we extend the previous results of holographic renormalization group flows to dimensions two. By introducing a superpotential, we derive the flow equations in two-dimensional dilaton gravity. We find a quantity which monotonically decreases along flows and give some comments on holographic $c$-theorem. As examples, we show that recently studied supersymmetric $AdS$ black hole solutions generically dimensionally reduce to two-dimensional dilaton gravity, and obtain the flow equations for black hole solutio…
We study the dilaton action induced by RG flows between holographic CFT fixed points. For this purpose we introduce a general bulk effective theory for the goldstone boson of the broken spacetime symmetry, providing an AdS analog of the EFT of Inflation. In two dimensions, we use the effective theory to compute the dilaton action, as well as the UV and IR conformal anomalies, without further assumptions. In higher dimensions we take a `slow-flow' limit analogous to the assumption of slow-roll in Inflation, and in this context we obtain the dilaton action, focusing on terms proportional to the …
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 four-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, $…
In this paper, we investigate the action growth in various backgrounds in Einstein-Maxwell-Dilaton theory. We calculate the full time evolution of action growth in AdS dilaton black hole and find it approaches the late time bound from above. We investigate the black hole which is asymptotically Lifshitz and obtain its late-time and full time behavior. We find the violation of Lloyd bound in late time limit and show the full time behavior exhibiting some new features for z sufficiently large.
