arXiv subjects

Harold Erbin

Publications and source records attributed to Harold Erbin.

43 records · Page 3Linked to original sources

arXiv2016

Deciphering and generalizing Demianski-Janis-Newman algorithm

In the case of vanishing cosmological constant, Demiański has shown that the Janis-Newman algorithm can be generalized in order to include a NUT charge and another parameter $c$, in addition to the angular momentum. Moreover it was proved that only a NUT charge can be added for non-vanishing cosmological constant. However despite the fact that the form of the coordinate transformations was obtained, it was not explained how to perform the complexification on the metric function, and the procedure does not follow directly from the usual Janis-Newman rules. The goal of our paper is threefold: explain the hidden assumptions of Demiański's analysis, generalize the computations to topological horizons (spherical and hyperbolic) and to charged solutions, and explain how to perform the complexification of the function. In particular we present a new solution which is an extension of the Demiański metric to hyperbolic horizons. These different results open the door to applications in (gauged) supergravity since they allow for a systematic application of the Demiański-Janis-Newman algorithm.

gr-qc↗

arXiv2015

Five-dimensional Janis-Newman algorithm

The Janis-Newman algorithm has been shown to be successful in finding new sta- tionary solutions of four-dimensional gravity. Attempts for a generalization to higher dimensions have already been found for the restricted cases with only one angular mo- mentum. In this paper we propose an extension of this algorithm to five dimensions with two angular momenta - using the prescription of G. Giampieri - through two specific examples, that are the Myers-Perry and BMPV black holes. We also discuss possible enlargements of our prescriptions to other dimensions and maximal number of angular momenta, and show how dimensions higher than six appear to be much more challenging to treat within this framework. Nonetheless this general algorithm provides a unification of the formulation in d = 3, 4, 5 of the Janis-Newman algorithm, from which which expose several examples including the BTZ black hole.

gr-qc↗

arXiv2015

Supergravity, complex parameters and the Janis-Newman algorithm

The Demiański-Janis-Newman algorithm is an original solution generating technique. For a long time it has been limited to producing rotating solutions, restricting to the case of a metric and real scalar fields, despite the fact that Demiański extended it to include more parameters such as a NUT charge. Recently two independent prescriptions have been given for extending the algorithm to gauge fields and thus electrically charged configurations. In this paper we aim to end setting up the algorithm by providing a missing but important piece, which is how the transformation is applied to complex scalar fields. We illustrate our proposal through several examples taken from N=2 supergravity, including the stationary BPS solutions from Behrndt et al. and Sen's axion-dilaton rotating black hole. Moreover we discuss solutions that include pairs of complex parameters, such as the mass and the NUT charge, or the electric and magnetic charges, and we explain how to perform the algorithm in this context (with the example of Kerr-Newman-Taub-NUT and dyonic Kerr-Newman black holes). The final formulation of the DJN algorithm can possibly handle solutions with five of the six Plebański-Demiański parameters along with any type of bosonic fields with spin less than two (exemplified with the SWIP solutions). This provides all the necessary tools for applications to general matter-coupled gravity and to (gauged) supergravity.

hep-th↗

arXiv2015

Quarter-BPS Black Holes in AdS$_4$-NUT from $N=2$ Gauged Supergravity

We study $N=2$ gauged supergravity with $U(1)$ gauge group coupled to $n_v$ vector multiplets and find quite general analytic solutions for quarter-BPS black holes with mass, NUT and dyonic Maxwell charges. The solutions we find have running scalar fields and flow in the IR region to a horizon geometry of the form AdS$_2\times Σ_g$.

hep-th↗

arXiv2015

Abelian Hypermultiplet Gaugings and BPS Vacua in N = 2 Supergravity

We analyze the gauging of Abelian isometries on the hypermultiplet scalar manifolds of N = 2 supergravity in four dimensions. This involves a study of symmetric special quaternionic-Kähler manifolds, building on the work of de Wit and Van Proeyen. In particular we compute the general set of Killing prepotentials and associated compensators for these manifolds manifolds. This allows us to glean new insights about AdS 4 vacua which preserve the full N = 2 supersymmetry as well as BPS static black hole horizons.

hep-th↗

arXiv2015

Janis-Newman algorithm: simplifications and gauge field transformation

The Janis-Newman algorithm is an old but very powerful tool to generate rotating solutions from static ones through a set of complex coordinate transformations. Several solutions have been derived in this way, including solutions with gauge fields. However, the transformation of the latter was so far always postulated as an ad hoc result. In this paper we propose a generalization of the procedure, extending it to the transformation of the gauge field. We also present a simplification of the algorithm due to G. Giampieri. We illustrate our prescription on the Kerr-Newman solution.

gr-qc↗

arXiv2012

Coupling of hard dimers to dynamical lattices via random tensors

We study hard dimers on dynamical lattices in arbitrary dimensions using a random tensor model. The set of lattices corresponds to triangulations of the d-sphere and is selected by the large N limit. For small enough dimer activities, the critical behavior of the continuum limit is the one of pure random lattices. We find a negative critical activity where the universality class is changed as dimers become critical, in a very similar way hard dimers exhibit a Yang-Lee singularity on planar dynamical graphs. Critical exponents are calculated exactly. An alternative description as a system of `color-sensitive hard-core dimers' on random branched polymers is provided.

cond-mat.stat-mech↗