Stationary Lifshitz black holes of R^2-corrected gravity theory

In this short note, I present a generalization of a set of static D-dimensional (D >= 3) Lifshitz black holes, which are solutions of the gravitational model obtained by amending the cosmological Einstein theory with the addition of only the curvature-scalar-squared term and that are described by two parameters, to a more general class of exact, analytic solutions that involves an additional parameter which now renders them stationary. In the special D=3 and the dynamical exponent z=1 case, the parameters can be adjusted so that the solution becomes identical to the celebrated BTZ black hole metric.Comment: 7 pages, no figures; ver. 2: added 5 new references (accepted by PRD as a Brief Report

Supersymmetric Strings and Waves in D=3, N=2 Matter Coupled Gauged Supergravities

We construct new 1/2 supersymmetric solutions in D=3, N=2, matter coupled, U(1) gauged supergravities and study some of their properties. In the most general case they represent a string superposed with gravitational and Chern-Simons electromagnetic waves. The waves are attached to the string and the solution satisfies an electromagnetic self-duality relation. When the sigma model is non-compact it interpolates between an asymptotically Kaigorodov space and a naked singularity. For the compact sigma model there is a regular horizon with the Kaigorodov geometry and asymptotically it is either Minkowskian or a pp-wave. When the sigma manifold is flat our solutions describe either AdS_3 or Kaigorodov space or a pp-wave in AdS_3.Comment: 19 pages, 1 figure, v2:a reference added, minor improvement

Kundt solutions of Minimal Massive 3D Gravity

We construct Kundt solutions of Minimal Massive Gravity theory and show that, similar to Topologically Massive Gravity (TMG), most of them are constant scalar invariant (CSI) spacetimes, that correspond to deformations of round and warped (A)dS. We also find an explicit non-CSI Kundt solution at the merger point. Finally, we give their algebraic classification with respect to the traceless Ricci tensor (Segre classification) and show that their Segre-types match with the types of their counterparts in TMG.Comment: 18 pages, no figures; ver. 2: a new (explicit, exact) non-CSI solution has been added, main text improved and references updated 20 pages, no figures; ver. 3: version accepted for publication in Physical Review

Shock-Free Wave Propagation in Gauge Theories

We present the shock-free wave propagation requirements for massless fields. First, we briefly argue how the "completely exceptional" approach, originally developed to study the characteristics of hyperbolic systems in 1+1 dimensions, can be generalized to higher dimensions and used to describe propagation without emerging shocks, with characteristic flow remaining parallel along the waves. We then study the resulting requirements for scalar, vector, vector-scalar and gravity models and characterize physically acceptable actions in each case.Comment: 30 pages, LaTeX, no figure

Hamiltonian Electric/Magnetic Duality and Lorentz Invariance

In (3+1) Hamiltonian form, the conditions for the electric/magnetic invariance of generic self-interacting gauge vector actions and the definition of the duality generator are obvious. Instead, (3+1) actions are not intrinsically Lorentz invariant. Imposing the Dirac-Schwinger stress tensor commutator requirement to enforce the latter yields a differential constraint on the Hamiltonian which translates into the usual Lagrangian form of the duality invariance condition obeyed by Maxwell and Born-Infeld theories. We also discuss covariance properties of some analogous scalar models.Comment: 7 pages, LaTeX, no figure

Negative Mass Solitons in Gravity

We first reconstruct the conserved (Abbott-Deser) charges in the spin connection formalism of gravity for asymptotically (Anti)-de Sitter spaces, and then compute the masses of the AdS soliton and the recently found Eguchi-Hanson solitons in generic odd dimensions, unlike the previous result obtained for only five dimensions. These solutions have negative masses compared to the global AdS or AdS/Z_p spacetimes. As a separate note, we also compute the masses of the recent even dimensional Taub-NUT-Reissner-Nordstrom metrics.Comment: 12 pages, RevTEX4; typos fixed; v3: version to appear in PRD, references adde

On the thermodynamics of Lifshitz black holes

We apply the recently extended conserved Killing charge definition of Abbott-Deser-Tekin formalism to compute, for the first time, the energies of analytic Lifshitz black holes in higher dimensions. We then calculate the temperature and the entropy of this large family of solutions, and study and discuss the first law of black hole thermodynamics. Along the way we also identify the possible critical points of the relevant quadratic curvature gravity theories. Separately, we also apply the generalized Killing charge definition to compute the energy and the angular momentum of the warped AdS_3 black hole solution of the three-dimensional New Massive Gravity theory.Comment: 16 pages, no figures, 1 table; ver 2: 2 new references added; ver 3: revision of the discussion on the obtained results, new references added, version accepted for publication in Physical Review