On the existence of topological dyons and dyonic black holes in anti-de Sitter Einstein-Yang-Mills theories with compact semisimple gauge groups

Here we study the global existence of “hairy” dyonic black hole and dyon solutions to four-dimensional, anti-de Sitter Einstein-Yang-Mills theories for a general simply connected and semisimple gauge group G, for the so-called topologically symmetric systems, concentrating here on the regular case.We generalise here cases in the literature which considered purely magnetic spherically symmetric solutions for a general gauge group and topological dyonic solutions for su(N). We are able to establish the global existence of non-trivial solutions to all such systems, both near existing embedded solutions and as the absolute value of Lambda goes to infinity. In particular, we can identify non-trivial solutions where the gauge field functions have no zeroes, which in the su(N) case proved important to stability. We believe that these are the most general analytically proven solutions in 4D anti-de Sitter Einstein-Yang-Mills systems to date

On the stability of soliton and hairy black hole solutions of SU(N) Einstein-Yang-Mills theory with a negative cosmological constant

We investigate the stability of spherically symmetric, purely magnetic, soliton and black hole solutions of four-dimensional su(N) Einstein-Yang-Mills theory with a negative cosmological constant Λ. These solutions are described by N − 1 magnetic gauge field functions ωj. We consider linear, spherically symmetric, perturbations of these solutions. The perturbations decouple into two sectors, known as the sphaleronic and gravitational sectors. For any N, there are no instabilities in the sphaleronic sector if all the magnetic gauge field functions ωj have no zeros and satisfy a set of N − 1 inequalities. In the gravitational sector, we prove that there are solutions which have no instabilities in a neighbourhood of stable embedded su(2) solutions, provided the magnitude of the cosmological constant |Λ| is sufficiently large. Kewywords : Stability, hairy black hole, soliton, Einstein-Yang-Mills, anti de-Sitte

Topological black holes in su(N) Einstein-Yang-Mills theory with a negative cosmological constant

We investigate the phase space of topological black hole solutions of su(N) Einstein-Yang-Mills theory in anti-de Sitter space with a purely magnetic gauge potential. The gauge field is described by N−1 magnetic gauge field functions ω_j, j=1,…,N−1. For su(2) gauge group, the function ω1 has no zeros. This is no longer the case when we consider a larger gauge group. The phase space of topological black holes is considerably simpler than for the corresponding spherically symmetric black holes, but for N>2 and a flat event horizon, there exist solutions where at least one of the ωj functions has one or more zeros. For most of the solutions, all the ωj functions have no zeros, and at least some of these are linearly stable

Existence of topological hairy dyons and dyonic black holes in anti-de Sitter SU(N) Einstein-Yang-Mills theory

We investigate dyonic black hole and dyon solutions of four-dimensional SU(N) Einstein-Yang-Mills theory with a negative cosmological constant. We derive a set of field equations in this case, and prove the existence of non-trivial solutions to these equations for any integer N, with 2N − 2 gauge degrees of freedom. We do this by showing that solutions exist locally at infinity, and at the event horizon for black holes and the origin for solitons. We then prove that we can patch these solutions together regularly into global solutions that can be integrated arbitrarily far into the asymptotic regime. Our main result is to show that dyonic solutions exist in open sets in the parameter space, and hence that we can find non-trivial dyonic solutions in a number of regimes whose magnetic gauge fields have no zeros, which is likely important to the stability of the solutions. Keywords : Dyons, Black holes, topological, SU(N), EYM, Existenc

Measurements of the Complex Conductivity of NbxSi1-x Alloys on the Insulating Side of the Metal-Insulator Transition

We have conducted temperature and frequency dependent transport measurements in amorphous Nb_x Si_{1-x} samples in the insulating regime. We find a temperature dependent dc conductivity consistent with variable range hopping in a Coulomb glass. The frequency dependent response in the millimeter-wave frequency range can be described by the expression $sigma(omega) \propto (-\imath omega)^alpha$ with the exponent somewhat smaller than one. Our ac results are not consistent with extant theories for the hopping transport.Comment: 4 pages with 3 figures; published version has a different title from original (was: "Electrodynamics in a Coulomb glass"

On the global existence of hairy black holes and solitons in anti-de Sitter Einstein-Yang-Mills theories with compact semisimple gauge groups

We investigate the existence of black hole and soliton solutions to four dimensional, anti-de Sitter (adS), Einstein-Yang-Mills theories with general semisimple connected and simply connected gauge groups, concentrating on the so-called 'regular case'. We here generalise results for the asymptotically flat case, and compare our system with similar results from the well researched adS su(N) system. We find the analysis differs from the asymptotically flat case in some important ways: the biggest difference is that for Λ < 0, solutions are much less constrained as r → ∞, making it possible to prove the existence of global solutions to the field equations in some neighbourhood of existing trivial solutions, and in the limit of |Λ| → ∞. In particular, we can identify non-trivial solutions where the gauge field functions have no zeroes, which in the su(N) case proved important to stability

Translating novel strategies for cardioprotection: the Hatter Workshop Recommendations

Ischemic heart disease (IHD) is the leading cause of death worldwide. Novel cardioprotective strategies are therefore required to improve clinical outcomes in patients with IHD. Although a large number of novel cardioprotective strategies have been discovered in the research laboratory, their translation to the clinical setting has been largely disappointing. The reason for this failure can be attributed to a number of factors including the inadequacy of the animal ischemia–reperfusion injury models used in the preclinical cardioprotection studies and the inappropriate design and execution of the clinical cardioprotection studies. This important issue was the main topic of discussion of the UCL-Hatter Cardiovascular Institute 6th International Cardioprotection Workshop, the outcome of which has been published in this article as the “Hatter Workshop Recommendations”. These have been proposed to provide guidance on the design and execution of both preclinical and clinical cardioprotection studies in order to facilitate the translation of future novel cardioprotective strategies for patient benefit