Anti-de Sitter Background Research Articles

Flowing along the edge: Spinning up black holes in AdS spacetimes with test particles

We investigate the consequences of throwing point particles into odd-dimensional Myers-Perry black holes in asymptotically anti-de Sitter (AdS) backgrounds. We restrict our attention to the case in which the angular momenta of the background geometry are all equal. This process allows us to test the generalization of the weak cosmic censorship conjecture to asymptotically AdS spacetimes in higher dimensions. We find no evidence for overspinning in D = 5, 7, 9 and 11 dimensions. Instead, test particles carrying the maximum possible angular momentum that still fall into an extremal rotating black hole generate a flow along the curve of extremal solutions.

Maxwell’s Equal Area Law and the Hawking-Page Phase Transition

We study the phases of a Schwarzschild black hole in the Anti-deSitter background geometry. Exploiting fluid/gravity duality, we construct the Maxwell equal area isotherm in the temperature-entropy plane, in order to eliminate negative heat capacity BHs. The construction we present here is reminiscent of the isobar cut in the pressure-volume plane which eliminates unphysical part of the Van der Walls curves below the critical temperature. Our construction also modifies the Hawking-Page phase transition. Stable BHs are formed at the temperature , while pure radiation persists for . turns out to be below the standard Hawking-Page temperature and there are no unstable BHs as in the usual scenario. Also, we show that, in order to reproduce the correct BH entropy , one has to write a black hole equation of state, that is, , in terms of the geometrical volume .

Correlators of circular Wilson loops from holography

We study the correlators of two circular Wilson loops of different radii at strong coupling. In our setup one Wilson loop is located inside the other. We use holography to calculate the connected two-point function. Both an anti-de Sitter background and a confining background are considered. As the computation for the confining case cannot be carried out analytically, we solve the problem numerically. In the anti-de Sitter case, our results agree with similar holographic calculations. In the case of a confining background, we find an asymptotic area law, in agreement with the result of the lattice strong coupling expansion. We also elaborate on the subtle issue of the interplay between connected and disconnected string world sheets.

ONE-DIMENSIONAL SUPERSYMMETRIC ALGEBRAS IN COLOR SUPERCONDUCTORS AND REISSNER–NORDSTRÖM–ANTI-DE SITTER GRAVITATIONAL SYSTEMS

We study two fermionic systems that have an underlying supersymmetric structure, namely a color superconductor and Dirac fermion in a Reissner–Nordström–anti-de Sitter gravitational background. In the chiral limit of the color superconductor, the localized fermionic zero modes around the vortex form an N = 2 with zero central charge d = 1 quantum algebra, with all the operators being Fredholm. We compute the Witten index of this algebra and we find an unbroken supersymmetry. The fermionic gravitational system in the chiral limit too, has two underlying unbroken N = 2, d = 1 supersymmetric algebras. The unbroken supersymmetry in the later is guaranteed by the existence of fermionic quasinormal modes in the Reissner–Nordström–anti-de Sitter background. In this case the operators are not Fredholm and regularized indices are deployed.

Maxwellʼs equal-area law for charged Anti-de Sitter black holes

In this Letter we present the construction of the Maxwell equal-area law in the Hawking temperature graph for a charged black hole in Anti-de Sitter background. We are able to find exact solution for the corresponding isotherm and entropies for “gaseous” (large) black holes and “liquid” (near-extremal) black holes. Isothermal construction removes the unphysical, negative heat capacity, regions. Furthermore, extremal black holes turn out to be dual to un-shrinkable molecules of Van der Waals real fluid, which may explain their thermodynamical stability.

New representation of the nonlocal ghost-free gravity theory

A new representation is found for the action of the recently suggested ghost-free nonlocal gravity models generating de Sitter or Anti-de Sitter background with an arbitrary value of the effective cosmological constant. This representation allows one to extend applications of these models from maximally symmetric to generic Einstein spaces and black hole solutions, but clearly indicates violation of the general relativistic limit in this class of theories, induced by their infrared behavior. It is shown that this limit can be recovered in a special conformal frame of these theories, and their relation to critical gravity models is also briefly discussed.

Holographic repulsion and confinement in gauge theory

We show that for asymptotically anti-de Sitter (AdS) backgrounds with negative energy, such as the AdS soliton and regulated negative-mass AdS–Schwarzshild metrics, the Wilson loop expectation value in the AdS/CFT conjecture exhibits a Coulomb to confinement transition. We also show that the quark–antiquark () potential can be interpreted as affine time along null geodesics on the minimal string worldsheet and that its intrinsic curvature provides a signature of transition to confinement phase. Our results suggest a generic (holographic) relationship between confinement in gauge theory and repulsive gravity, which in turn is connected with singularity avoidance in quantum gravity.Communicated by P R L V Moniz

Generalized particle dynamics in anti de Sitter spaces: mimicking a phantom dark energy

We consider a generalized particle dynamics in brane world formalism in an (4+1)-asymptotically anti de Sitter background. This generalized particle dynamics model induces an effective (4+1)-dimensional spacetime and (3+1)-dimensional physical universe is then embedded in this effective spacetime. The embedding framework induces an effective Dark Energy equation of state which is dynamical in nature and exhibits a phantom like behavior. We then corroborate our results with present day observed cosmological parameters.

New exact solutions of quadratic curvature gravity

It is a known fact that the Kerr-Schild type solutions in general relativity satisfy both exact and linearized Einstein field equations. We show that this property remains valid also for a special class of the Kerr-Schild metrics in arbitrary dimensions in generic quadratic curvature theory. In addition to the anti-de Sitter (AdS) wave (or Siklos) metric which represents plane waves in an AdS background, we present here a new exact solution, in this class, to the quadratic gravity in $D$ dimensions which represents a spherical wave in an AdS background. The solution is a special case of the Kundt metrics belonging to spacetimes with constant curvature invariants.

Anisotropic hydrodynamics, holography, and the chiral magnetic effect

We discuss a possible dependence of the chiral magnetic effect (CME) on the elliptic flow coefficient ${v}_{2}$. We first study this in a hydrodynamic model for a static anisotropic plasma with multiple anomalous $U(1)$ currents. In the case of two charges, one axial and one vector, the CME formally appears as a first-order transport coefficient in the vector current. We compute this transport coefficient and show its dependence on ${v}_{2}$. We also determine the CME coefficient from first-order corrections to the dual anti-de Sitter background using the fluid-gravity duality. For small anisotropies, we find numerical agreement with the hydrodynamic result.

Critical gravity with a scalar field in four dimensions

We consider the critical gravity theory with a scalar field in four dimensions. We find that this theory has the solution corresponding to the de Sitter (dS), anti-de Sitter (AdS), and Minkowski background depending on whether the action includes the cosmological term or not. The Minkowski background is the solution which cannot be obtained in the model without a scalar field. At the critical point, we show that the Abbott-Deser (AD) mass of the Schwarzschild-de Sitter (SdS) black hole and the energy for the massless graviton vanish, whose situation is not changed from the model without a scalar field.

Serendipitous discoveries in nonlocal gravity theory

We present a class of generally covariant nonlocal gravity models which have a flat-space general relativistic (GR) limit and also possess a stable de Sitter (dS) or Anti-de Sitter (AdS) background with an arbitrary value of its cosmological constant. The nonlocal action of the theory is formulated in the Euclidean signature spacetime and is understood as an approximation to the quantum effective action (generating functional of one-particle irreducible diagrams) originating from fundamental quantum gravity theory. Using the known relation between the Schwinger-Keldysh technique for quantum expectation values and the Euclidean quantum field theory we derive from this action the {\em causal} effective equations of motion for mean value of the metric field in the physical Lorentzian-signature spacetime. Thus we show that the (A)dS background of the theory carries as free propagating modes massless gravitons having two polarizations identical to those of the Einstein theory with a cosmological term. The on-shell action of the theory is vanishing both for the flat-space and (A)dS backgrounds which play the role of stable vacua underlying respectively the ultraviolet and infrared phases of the theory. We also obtain linearized gravitational potentials of compact matter sources and show that in the infrared (A)dS phase their effective gravitational coupling $G_{\rm eff}$ can be essentially different from the Newton gravitational constant $G_N$ of the short-distance GR phase. When $G_{\rm eff}\gg G_N$ the (A)dS phase can be regarded as a strongly coupled infrared modification of Einstein theory not only describing the dark energy mechanism of cosmic acceleration but also simulating the dark matter phenomenon by enhanced gravitational attraction at long distances.

Unitarity of Weyl-invariant new massive gravity and generation of graviton mass via symmetry breaking

We give a detailed analysis of the particle spectrum and the perturbative unitarity of the recently introduced Weyl-invariant version of the new massive gravity in 2+1 dimensions. By computing the action up to second order in the fluctuations of the metric, the gauge and the scalar fields around the anti-de Sitter (AdS) and flat vacua, we find that the theory describes unitary (tachyon and ghost-free) massive spin-2, massive (or massless) spin-1 and massless spin-0 excitations for certain ranges of the dimensionless parameters. The theory is not unitary in de Sitter space. Scale invariance is either broken spontaneously (in AdS background) or radiatively (in flat background) and hence the masses of the particles are generated either spontaneously or at the second loop order.

NONSTATIC CHARGED BTZ-LIKE BLACK HOLES IN N+1 DIMENSIONS

We find an exact nonstatic charged BTZ-like solutions, in (N+1)-dimensional Einstein gravity in the presence of negative cosmological constant and a nonlinear Maxwell field defined by a power s of the Maxwell invariant, which describes the gravitational collapse of charged null fluid in an anti-de Sitter background. Considering the situation that a charged null fluid injects into the initially an anti-de Sitter spacetime, we show that a black hole form rather than a naked singularity, irrespective of spacetime dimensions, from gravitational collapse in accordance with cosmic censorship conjecture. The structure and locations of the apparent horizons of the black holes are also determined. It is interesting to see that, in the static limit and when N = 2, one can retrieve 2+1 BTZ black hole solutions.

Dark energy and dark matter from nonlocal ghost-free gravity theory

We suggest a class of generally covariant ghost-free nonlocal gravity models generating de Sitter or anti-de Sitter background with an arbitrary value of the effective cosmological constant and featuring a mechanism of dark matter simulation. These models interpolate between the general relativistic phase on a flat spacetime background and their strongly coupled infrared (anti-)de Sitter phase with two propagating massless graviton modes.

Dynamical formation and evolution of (2+1)-dimensional charged black holes

In this paper, we investigate the dynamical formation and evolution of (2 + 1)-dimensional charged black holes. We numerically study dynamical collapses of charged matter fields in an anti-de Sitter background and note the formation of black holes using the double-null formalism. Moreover, we include renormalized energy–momentum tensors assuming the S-wave approximation to determine thermodynamical back-reactions to the internal structures. If there are no semi-classical effects, the amount of charge determines the causal structures. If the charge is sufficiently small, the causal structure has a space-like singularity. However, as the charge increases, an inner Cauchy horizon appears. If we have sufficient charge, we see a space-like outer horizon and a time-like inner horizon, and if we give excessive charge, black hole horizons disappear. We have some circumstantial evidence that weak cosmic censorship is still satisfied, even for such excessive charge cases. Also, we confirm that there is mass inflation along the inner horizon, although the properties are quite different from those of four-dimensional cases. Semi-classical back-reactions will not affect the outer horizon, but they will affect the inner horizon. Near the center, there is a place where negative energy is concentrated. Thus, charged black holes in three dimensions have two types of curvature singularities in general: via mass inflation and via a concentration of negative energy. Finally, we classify possible causal structures.

Oscillating instanton solutions in curved space

We investigate oscillating instanton solutions of a self-gravitating scalar field between degenerate vacua. We show that there exist O(4)-symmetric oscillating solutions in a de Sitter background. The geometry of this solution is finite and preserves the $Z_{2}$ symmetry. The nontrivial solution corresponding to tunneling is possible only if the effect of gravity is taken into account. We present numerical solutions of this instanton, including the phase diagram of solutions in terms of the parameters of the present work and the variation of energy densities. Our solutions can be interpreted as solutions describing an instanton-induced domain wall or braneworld-like object rather than a kink-induced domain wall or braneworld. The oscillating instanton solutions have a thick wall and the solutions can be interpreted as a mechanism providing nucleation of the thick wall for topological inflation. We remark that $Z_{2}$ invariant solutions also exist in a flat and anti-de Sitter background, though the physical significance is not clear.

The Konishi multiplet at strong coupling

We introduce a method to compute from first principles the anomalous dimension of short operators in N=4 super Yang-Mills theory at strong coupling, where they are described in terms of superstring vertex operators in an anti-de Sitter background. We focus on the Konishi multiplet, dual to the first massive level of the superstring, and compute the one-loop correction to its anomalous dimension at strong coupling, using the pure spinor formalism for the superstring.

Three-dimensional $ \mathcal{N} = 2 $ (AdS) supergravity and associated supercurrents

Long ago, Achucarro and Townsend discovered that in three dimensions (3D) N-extended anti-de Sitter (AdS) supergravity exists in several incarnations, which were called the (p,q) AdS supergravity theories with non-negative integers p>=q such that N=p+q. Using the superspace approach to 3D N-extended supergravity developed in arXiv:1101.4013, we present three superfield formulations for N=2 supergravity that allow for well defined cosmological terms and supersymmetric AdS solutions. The conformal compensators corresponding to these theories are respectively: (i) a chiral scalar multiplet: (ii) a vector multiplet; and (iii) an improved complex linear multiplet. The theories corresponding to (i) and (iii) are shown to provide two dually equivalent realizations of the (1,1) AdS supergravity, while (ii) describes the (2,0) AdS supergravity. We associate with each supergravity formulation, with and without a cosmological term, a consistent supercurrent multiplet. The supercurrents in the (1,1) and (2,0) AdS backgrounds are derived for the first time. We elaborate on rigid supersymmetric theories in (1,1) and (2,0) AdS superspaces.

Gravitational cubic interactions for a simple mixed-symmetry gauge field in AdS and flat backgrounds

Cubic interactions between the simplest mixed-symmetry gauge field and gravity are constructed in anti-de Sitter (AdS) and flat backgrounds. Non-Abelian cubic interactions are obtained in AdS following various perturbative methods including the Fradkin–Vasiliev construction, with and without Stückelberg fields. The action that features the maximal number of Stückelberg fields can be considered in the flat limit without loss of physical degrees of freedom. The resulting interactions in flat space are compared with a classification of vertices obtained via the antifield cohomological perturbative method. It is shown that the gauge algebra becomes Abelian in the flat limit, in contrast to what happens for totally symmetric gauge fields in AdS.