Anti-de Sitter Solutions Research Articles

Uniqueness of the extremal Schwarzschild de Sitter spacetime

We prove that any analytic vacuum spacetime with a positive cosmological constant in four and higher dimensions, that contains a static extremal Killing horizon with a maximally symmetric compact cross-section, must be locally isometric to either the extremal Schwarzschild de Sitter solution or its near-horizon geometry (the Nariai solution). In four-dimensions, this implies these solutions are the only analytic vacuum spacetimes that contain a static extremal horizon with compact cross-sections (up to identifications). We also consider the analogous uniqueness problem for the four-dimensional extremal hyperbolic Schwarzschild anti-de Sitter solution and show that it reduces to a spectral problem for the laplacian on compact hyperbolic surfaces, if a cohomological obstruction to the uniqueness of infinitesimal transverse deformations of the horizon is absent.

Reissner–Nordström black holes in quintic quasi-topological gravity

This paper investigates charged black holes within the framework of quintic quasi-topological gravity, focusing on their thermodynamics, conserved quantities, and stability. We construct numerical solutions and explore their thermodynamic properties, supplemented by the study of analytically solvable special cases. By verifying the first law of thermodynamics, we validate our approach and compare our findings to those of Einstein gravity. The physical properties of the solutions are examined across anti-de Sitter, de Sitter, and flat spacetime backgrounds. Our analysis reveals that anti-de Sitter solutions demonstrate thermal stability, while de Sitter and flat solutions lack this property. Finally, we discuss the implications of our results and propose potential avenues for future research in this field.

Extensions of a scale-separated AdS4 solution and their mass spectrum

We consider two extensions of the so-called DGKT solution, a 4d scale-separated anti-de Sitter (AdS) solution obtained as a compactification on a 6d torus orbifold. Each extension consists in a specific large n expansion beyond the DGKT solution, where n is the unbounded F4-flux parameter. One of the extensions considered generalizes the known warped, partially backreacted solution. We analyse the two extensions in 10d massive type IIA supergravity as well as in a 4d effective theory, using a general warped compactification formalism, including axions. On top of known corrections to DGKT, we mainly get new ones from F4; other fluxes are very constrained by flux quantization. In each extension, one would expect corresponding corrections to the mass spectrum, before reaching contributions from α′-corrections. But the mass spectrum turns out to be robust, and conformal dimensions remain unchanged.

Rotating black strings beyond Maxwell's electrodynamics

In this paper, we investigate the asymptotically Anti-de Sitter solutions of rotating black strings coupled to Born-Infeld and Modified Maxwell non-linear electrodynamics in the context of Einsteinian, Einsteinian cubic and Einsteinian quartic gravity. By studying the near-horizon behavior of solutions, we find the mass parameter, surface gravity and accordingly the Hawking temperature. We also compute the entropy, mass, angular momentum, electric charge, and the electrostatic potential of solutions to show that, in the context of above theories and in the presence of two mentioned non-linear electrodynamics, the first law of thermodynamics for rotating black strings is also exactly hold. We also investigate extremality, thermal stability and phase transition of solutions.

Gauss-Bonnet solution with a cloud of strings in de Sitter and anti-de Sitter space* *Supported by the National Natural Science Foundation of China (12275087) and the Fundamental Research Funds for the Central Universities.

In this study, we investigate exact spherically symmetric Gauss-Bonnet black hole solutions surrounded by a cloud of string fluid with the cosmological constant in dimensions. Both charged and uncharged cases are considered. We focus on the de Sitter solutions in the main text and provide the anti-de Sitter solutions in the appendix. We analyze the features of event horizons and thermodynamic properties of the black hole solutions. The mass, Hawking temperature, thermal stability, and phase transitions are discussed. Moreover, the equation of state and critical phenomena associated with these solutions are explored.

Conformal renormalization of scalar-tensor theories

We study a conformally coupled scalar-tensor theory with a quartic potential possessing local conformal symmetry up to a boundary term. We show that requiring the restoration of the full local conformal symmetry fixes the counterterms that render the on-shell action finite. The building block of the resulting action is a conformally covariant tensor which is constructed out of the metric and the scalar field and it has the same conformal weight as the Weyl tensor. This allows us to obtain the counterterms for the scalar-tensor sector in a closed form. The finiteness of the conformally complete version of the action is suggestive on the validity of the conformal renormalization prescription. We extend this theory by adding the conformal gravity action and also the Einstein-AdS action written in MacDowell-Mansouri form. Even though the latter breaks the conformal symmetry, we find that the action is still renormalized provided a suitable falloff of the scalar field when considering asymptotically locally anti-de Sitter solutions. Black hole solutions in these theories are studied, for which the Hawking temperature and the partition function to first order in the saddle-point approximation are calculated, providing a concrete example of this renormalization scheme.

Negative scalar potentials and the swampland: an Anti-Trans-Planckian Censorship Conjecture

In this paper, we derive a characterisation of negative scalar potentials, V < 0, in d-dimensional effective theories of quantum gravity. This is achieved thanks to an Anti-Trans-Planckian Censorship Conjecture (ATCC), inspired by a refined version of the TCC. The ATCC relies on the fact that in a contracting universe, modes that become sub-Planckian in length violate the validity of the effective theory. In the asymptotics of field space, we deduce that −V′/V ≥ c0 when V′ ≥ 0. The rate {c}_0=2/sqrt{left(d-1right)left(d-2right)} is successfully tested in several string compactifications for d ≥ 4. In addition, a new asymptotic condition, V′′/V ≥ {c}_0^2 , is derived. By extrapolation to anti-de Sitter solutions of radius l, we infer the existence of a scalar whose mass should obey m2l2 ≲ −2. This property is verified in many supersymmetric examples.

Holographic Characterisation of Locally Anti-de Sitter Spacetimes

It is shown that an (n+1)-dimensional asymptotically anti-de Sitter solution of the Einstein-vacuum equations is locally isometric to pure anti-de Sitter spacetime near a region of the conformal boundary if and only if the boundary metric is conformally flat and (for n ne 4) the boundary stress–energy tensor vanishes, subject to (i) sufficient (finite) regularity in the metric and (ii) the satisfaction of a conformally invariant geometric criterion on the boundary region. A key tool in the proof is the Carleman estimate of Chatzikaleas and Shao (Commun Math Phys, 2022)—a generalisation of previous work by the author with McGill and Shao in (Class Quant Gravity 38(5), 2020)—which is applied to prove a unique continuation result for the Weyl curvature at the conformal boundary given vanishing to sufficiently high order over the boundary region.

Charged rotating black strings in Einsteinian quartic gravity

We find an analytic asymptotically anti-de Sitter solution for charged rotating black strings in Einsteinian quartic gravity. By studying the near-horizon behavior of the solutions, we independently extract their thermodynamic properties, analytically. As a consistency check, we show that the first law of thermodynamics for rotating black strings holds exactly in both charged and uncharged cases.

Testing dynamical torsion effects on the charged black hole’s shadow, deflection angle and greybody with M87* and Sgr. A* from EHT

Poincaré Gauge’s theory of gravity is the most noteworthy alternative extension of general relativity that has a correspondence between spin and spacetime geometry. In this paper, we use Reissner–Nordstrom–de Sitter and anti-de Sitter solutions, where torsion τ is added as an independent field, to analyze the weak deflection angles αˆ of massive and null particles in finite distance regime. We then apply αˆ to determine the Einstein ring formation in M87* and Sgr. A* and determine that relative to Earth’s location from these black holes, massive torsion effects can provide considerable deviation, while the cosmological constant’s effect remains negligible. Furthermore, we also explore how the torsion parameter affects the shadow radius perceived by both static and co-moving (with cosmic expansion) observers in a Universe dominated by dark energy, matter, and radiation. Our findings indicate that torsion and cosmological constant parameters affect the shadow radius differently between observers in static and co-moving states. We also show how the torsion parameter affects the luminosity of the photonsphere by studying the shadow with infalling accretion. The calculation of the quasinormal modes, greybody bounds, and high-energy absorption cross-section are also affected by the torsion parameter considerably.

Automated consistent truncations and stability of flux compactifications

Classical flux compactifications contribute to a well-controlled corner of the string landscape, therefore providing an important testing ground for a variety of conjectures. We focus here on type II supergravity compactifications on 6d group manifolds towards 4d maximally symmetric spacetimes. We develop a code where the truncation to left-invariant scalars and the dimensional reduction to a 4d theory are automated, for any possible configuration of Op-planes and Dp-branes. We then prove that any such truncation is consistent. We further compute the mass spectrum and analyse the stability of many de Sitter, Minkowski or anti-de Sitter solutions, as well as their consistency with swampland conjectures.

An infinity of black holes

In general relativity (without matter), there is typically a one parameter family of static, maximally symmetric black hole solutions labeled by their mass. We show that there are situations with many more black holes. We study asymptotically anti-de Sitter solutions in six and seven dimensions having a conformal boundary which is a product of spheres cross time. We show that the number of families of static, maximally symmetric black holes depends on the ratio, λ, of the radii of the boundary spheres. As λ approaches a critical value, λ c , the number of such families becomes infinite. In each family, we can take the size of the black hole to zero, obtaining an infinite number of static, maximally symmetric non-black hole solutions. We discuss several applications of these results, including Hawking–Page phase transitions and the phase diagram of dual field theories on a product of spheres, new positive energy conjectures, and more.

Kaluza-Klein fermion mass matrices from exceptional field theory and mathcal{N} = 1 spectra

Using Exceptional Field Theory, we determine the infinite-dimensional mass matrices for the gravitino and spin-1/2 Kaluza-Klein perturbations above a class of anti-de Sitter solutions of M-theory and massive type IIA string theory with topologically-spherical internal spaces. We then use these mass matrices to compute the spectrum of Kaluza-Klein fermions about some solutions in this class with internal symmetry groups containing SU(3). Combining these results with previously known bosonic sectors of the spectra, we give the complete spectrum about some mathcal{N} = 1 and some non-supersymmetric solutions in this class. The complete spectra are shown to enjoy certain generic features.

Riemannian manifolds dual to static spacetimes

We establish a one-to-one correspondence between static spacetimes and Riemannian manifolds that maps causal geodesics to geodesics, as suggested by L. C. Epstein. We then explore constant curvature spacetimes - such as the de Sitter and the anti-de Sitter universes - and find that they map to constant curvature Riemannian manifolds, namely the Euclidean space, the sphere and the hyperbolic space. By imposing the conditions required to map to the sphere, we obtain the spherically symmetric metrics for which there is radial oscillatory motion with a period independent of the amplitude. We then consider the case of a perfect fluid and an Einstein cluster and determine the pressure and density profiles required to find this type of motion. Finally, we give examples of surfaces corresponding to certain types of motion for metrics that do not exhibit constant curvature, such as the Schwarzschild, Schwarzschild de Sitter and Schwarzschild anti-de Sitter solutions, and even for a simplified model of a wormhole.

Boundary conditions and vacuum fluctuations in {mathrm {AdS}}_4

Initial conditions given on a spacelike, static slice of a non-globally hyperbolic spacetime may not define the fates of classical and quantum fields uniquely. Such lack of global hyperbolicity is a well-known property of the anti-de Sitter solution and led many authors to question how is it possible to develop a quantum field theory on this spacetime. Wald and Ishibashi took a step towards the healing of that causal issue when considering the propagation of scalar fields on AdS. They proposed a systematic procedure to obtain a physically consistent dynamical evolution. Their prescription relies on determining the self-adjoint extensions of the spatial component of the differential wave operator. Such a requirement leads to the imposition of a specific set of boundary conditions at infinity. We employ their scheme in the particular case of the four-dimensional AdS spacetime and compute the expectation values of the field squared and the energy-momentum tensor, which will then bear the effects of those boundary conditions. We are not aware of any laws of nature constraining us to prescribe the same boundary conditions to all modes of the wave equation. Thus, we formulate a physical setup in which one of those modes satisfy a Robin boundary condition, while all others satisfy the Dirichlet condition. Due to our unusual settings, the resulting contributions to the fluctuations of the expectation values will not respect AdS invariance. As a consequence, a back-reaction procedure would yield a non-maximally symmetric spacetime. Furthermore, we verify the violation of weak energy condition as a direct consequence of our prescription for dynamics.

Thick branes in higher-dimensional f(R) gravity

We study the thick brane model within [Formula: see text] the modified gravity in [Formula: see text]-dimensional spacetimes with [Formula: see text]. The system under consideration consists of two branes orthogonal to each other: the four-dimensional Lorentzian brane and [Formula: see text]-dimensional Euclidean one. It is numerically shown that, for a given [Formula: see text], regular vacuum asymptotically anti-de Sitter solutions exist only in the range [Formula: see text]. Depending on the values of [Formula: see text] and boundary conditions imposed on the Lorentzian brane, the solutions can pass or not pass through a fixed point located on the Lorentzian brane, and also be [Formula: see text]-symmetric or nonsymmetric. In the large-[Formula: see text] limit, we find the approximate analytic solutions. It is also shown that a test scalar field is trapped on the Lorentzian brane at any [Formula: see text].

Cylindrically symmetric static n-dimensional (un)charged (anti-)de Sitter black holes in generic f(T) gravity

Given a generic function f(T) we construct in closed forms cylindrically symmetric static n-dimensional uncharged and charged de Sitter and anti-de Sitter solutions (including black holes, wormholes and possibly other regular solutions) in f(T) gravity. Applications to some known models are considered.

Gravitational corner conditions in holography

Contrary to popular belief, asymptotically anti-de Sitter solutions of gravitational theories cannot be obtained by taking initial data (satisfying the constraints) on a spacelike surface, and choosing an arbitrary conformal metric on the timelike boundary at infinity. There are an infinite number of corner conditions that also must be satisfied where the initial data surface hits the boundary. These are well known to mathematical relativists, but to make them more widely known we give a simple explanation of why these conditions exist and discuss some of their consequences. An example is given which illustrates their power. Some implications for holography are also mentioned.

Wrapped brane solutions in romans F(4) gauged supergravity

We explore the spectrum of lower-dimensional anti-de Sitter (AdS) solutions in F(4) gauged supergravity in six dimensions. The ansatz employed corresponds to D4-branes partially wrapped on various supersymmetric cycles in special holonomy manifolds. Re-visiting and extending previous results, we study the cases of two, three, and four-dimensional supersymmetric cycles within Calabi-Yau threefold, fourfold, G2, and Spin(7) holonomy manifolds. We also report on non-supersymmetric AdS vacua, and check their stability in the consistently truncated lower-dimensional effective action, using the Breitenlohner-Freedman bound. We also analyze the IR behavior and discuss the admissibility of singular flows.

Two-dimensional fluids and their holographic duals

We describe the dynamics of two-dimensional relativistic and Carrollian fluids. These are mapped holographically to three-dimensional locally anti-de Sitter and locally Minkowski spacetimes, respectively. To this end, we use Eddington–Finkelstein coordinates, and grant general curved two-dimensional geometries as hosts for hydrodynamics. This requires to handle the conformal anomaly, and the expressions obtained for the reconstructed bulk metrics incorporate non-conformal-fluid data. We also analyze the freedom of choosing arbitrarily the hydrodynamic frame for the description of relativistic fluids, and propose an invariant entropy current compatible with classical and extended irreversible thermodynamics. This local freedom breaks down in the dual gravitational picture, and fluid/gravity correspondence turns out to be sensitive to dissipation processes: the fluid heat current is a necessary ingredient for reconstructing all Bañados asymptotically anti-de Sitter solutions. The same feature emerges for Carrollian fluids, which enjoy a residual frame invariance, and their Barnich–Troessaert locally Minkowski duals. These statements are proven by computing the algebra of surface conserved charges in the fluid-reconstructed bulk three-dimensional spacetimes.