We perform a systematic search for anti-de Sitter vacua of maximal supergravity with N > 2 residual supersymmetries. We find that maximal supergravity admits two 1-parameter classes of N = 3 and N = 4 vacua, respectively. They are embedded, for the different values of an angular parameter, in the ω-rotated SO(8) (N = 3) and SO(1, 7) (N = 4 and 3) gauged models. All vacua disappear in the ω → 0 limit. We determine the mass spectra and the AdS-supermultiplet structure. These appear to be the first and only N > 2 supersymmetric AdS vacua in maximal supergravity, aside from the N = 8 vacua of the SO(8)-gauged models. We also prove on general grounds that no such vacua can exist for 4 < N < 8.

We provide the detailed calculation of a general form for Maxwell and London equations that takes into account gravitational corrections in linear approximation. We determine the possible alteration of a static gravitational field in a superconductor making use of the time-dependent Ginzburg-Landau equations, providing also an analytic solution in the weak field condition. Finally, we compare the behavior of a high-T c superconductor with a classical low-T c superconductor, analyzing the values of the parameters that can enhance the reduction of the gravitational field.

We consider non-extremal, stationary, axion-dilaton solutions to ungauged symmetric supergravity models, obtained by Harrison transformations of the non-extremal Kerr solution. We define a general algebraic procedure, which can be viewed as an Inönü-Wigner contraction of the Noether-charge matrix associated with the effective D = 3 sigma-model description of the solution, yielding, through different singular limits, the known BPS and non-BPS extremal black holes (which include the underrotating non-BPS one). The non-extremal black hole can thus be thought of as "interpolating" among these limit-solutions. The algebraic procedure that we define generalizes the known Rasheed-Larsen limit which yielded, in the Kaluza-Klein theory, the first instance of under-rotating extremal solution.As an example of our general result, we discuss in detail the non-extremal solution in the T 3 -model, with either q 0 , p 1 or p 0 , q 1 charges switched on, and its singular limits. Such solutions, computed in D = 3 through the solution-generating technique, is completely described in terms of D = 4 fields, which include the fully integrated vector fields.The study of stationary black holes in superstring/supergravity theories is a branch of research which has witnessed important progresses in the last two decades or so [1]. Initially, special attention was devoted to BPS and in general extremal solutions by virtue of their universal near-horizon behavior, due to the attractor phenomenon [2]. Multicenter extremal solutions in D = 4 have also been extensively studied in recent years [3,4,5,6].Our knowledge of non-extremal, stationary solutions is more restricted, due to the less constrained form of the space-time metric. The known examples are typically obtained through the so called solution-generating techniques [7]. The idea underlying this approach is that stationary solutions to D = 4 supergravity are also solutions to an Euclidean theory in three dimensions, formally obtained by compactifying the D = 4 parent model along the time-direction [8] and dualizing all the vector fields into scalars. The resulting D = 3 theory is a sigma-model coupled to gravity and has the desirable feature of having a larger global symmetry group than the original four-dimensional model. The extra symmetries can be used to generate new four-dimensional solutions from known ones. These symmetries, for instance, include the Harrison transformations which can generate electric and magnetic charges when acting on a neutral solution like the Schwarzschild or the Kerr black hole. The relevant physical properties of stationary black holes in four dimensions are thus conveniently described by the orbits of such solutions with respect to the action of the D = 3 global symmetry group G (3) .It is a commonly accepted statement in the black-hole literature that extremal solutions in supergravity can be obtained as limits of non-extremal ones. In the extremal limit a certain extremality parameter, related to the Hawking temperature of the black hole, is sent to ze...

In this article we study a family of four-dimensional, $$ \mathcal{N} $$ N = 2 supergravity theories that interpolates between all the single dilaton truncations of the SO(8) gauged $$ \mathcal{N} $$ N = 8 supergravity. In this infinitely many theories characterized by two real numbers — the interpolation parameter and the dyonic “angle” of the gauging — we construct non-extremal electrically or magnetically charged black hole solutions and their supersymmetric limits. All the supersymmetric black holes have non-singular horizons with spherical, hyperbolic or planar topology. Some of these supersymmetric and non-extremal black holes are new examples in the $$ \mathcal{N} $$ N = 8 theory that do not belong to the STU model. We compute the asymptotic charges, thermodynamics and boundary conditions of these black holes and show that all of them, except one, introduce a triple trace deformation in the dual theory.