53,880 research outputs found
New classes of bi-axially symmetric solutions to four-dimensional Vasiliev higher spin gravity
Indexación: Web of Science; Scopus; Scielo.We present new infinite-dimensional spaces of bi-axially symmetric asymptotically anti-de Sitter solutions to four-dimensional Vasiliev higher spin gravity, obtained by modifications of the Ansatz used in arXiv: 1107.1217, which gave rise to a Type-D solution space. The current Ansatz is based on internal semigroup algebras (without identity) generated by exponentials formed out of the bi-axial symmetry generators. After having switched on the vacuum gauge function, the resulting generalized Weyl tensor is given by a sum of generalized Petrov type-D tensors that are Kerr-like or 2-brane-like in the asymptotic AdS(4) region, and the twistor space connection is smooth in twistor space over finite regions of spacetime. We provide evidence for that the linearized twistor space connection can be brought to Vasiliev gauge.https://link.springer.com/article/10.1007%2FJHEP01%282017%2904
Pickering emulsions stabilized by hydrophilic nanoparticles: in situ surface modification by oil
We propose a novel route for the stabilization of oil-in-water Pickering emulsions using inherently hydrophilic nanoparticles. In the case of dialkyl adipate oils, in situ hydrophobisation of the particles by dissolved oil molecules in the aqueous phase enables stable emulsions to be formed. Emulsion stability is enhanced upon decreasing the chain length of the oil due to its increased solubility in the precursor aqueous phase. The oil thus acts like a surfactant in this respect in which hydrogen bonds form between the carbonyl group of the ester oil and the hydroxyl group on particle surfaces. The particles chosen include both fumed and precipitated anionic silica and cationic zirconia. Complementary experiments including relevant oil–water–solid contact angles and infra-red analysis of dried particles after contact with oil support the proposed mechanism
Rational material design of mixed-valent high T superconductors
We design, from first principles calculations, a novel family of thallium
halide-based compounds as candidates for new high temperature superconductors,
whose superconductivity is mediated by the recently proposed mechanism of
non-local correlation-enhanced strong electron-phonon coupling. Two prototype
compounds namely CsTlF and CsTlCl are studied with various hole doping
levels and volumes. The critical superconducting temperature T are
predicted to be about 30 K and 20 K with 0.35/f.u. hole doping and
require only modest pressures (10 and 2 GPa), respectively. Our
procedure of designing this class of superconductors is quite general and can
be used to search for other "other high temperature superconductors".Comment: 6- ages, EPL 101, 27002 (2013
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