Geometries with Killing Spinors and Supersymmetric AdS Solutions

The seven and nine dimensional geometries associated with certain classes of supersymmetric $AdS_3$ and $AdS_2$ solutions of type IIB and D=11 supergravity, respectively, have many similarities with Sasaki-Einstein geometry. We further elucidate their properties and also generalise them to higher odd dimensions by introducing a new class of complex geometries in $2n+2$ dimensions, specified by a Riemannian metric, a scalar field and a closed three-form, which admit a particular kind of Killing spinor. In particular, for $n\ge 3$, we show that when the geometry in $2n+2$ dimensions is a cone we obtain a class of geometries in $2n+1$ dimensions, specified by a Riemannian metric, a scalar field and a closed two-form, which includes the seven and nine-dimensional geometries mentioned above when $n=3,4$, respectively. We also consider various ansatz for the geometries and construct infinite classes of explicit examples for all $n$.Comment: 28 page

Experimental fitting to the bipolaronic model of the normal-state resistance of Bi_2Sr_2CaCu_2O_8 single crystals

Normal-state resistance data from Bi_2Sr_2CaCu_2O_8 single crystals were fitted to the (bi)polaronic conduction model, $R=R_0 (T+\sigma_b T^2)/(1+bT)$, with satisfactory agreement over a wide temperature range. The fluctuating conduction region is found to be much narrower than that in the usual sense, as is the case for a charged Bose-gas. We estimate the effective (bi)polaron mass to be ~ 4m_e.Comment: 2 pages + 2 postscript figures. Submitted to M2S-HTSC-VI(Houston) Conferenc

Marginal Deformations of Field Theories with AdS_4 Duals

We generate new AdS_4 solutions of D=11 supergravity starting from AdS_4 x X_7 solutions where X_7 has U(1)^3 isometry. We consider examples where X_7 is weak G_2, Sasaki-Einstein or tri-Sasakian, corresponding to d=3 SCFTs with N=1,2 or 3 supersymmetry, respectively, and where the deformed solutions preserve N=1,2 or 1 supersymmetry, respectively. For the special cases when X_7 is M(3,2), Q(1,1,1) or N(1,1)_I we identify the exactly marginal deformation in the dual field theory. We also show that the volume of supersymmetric 5-cycles of N(1,1)_I agrees with the conformal dimension predicted by the baryons of the dual field theory.Comment: 28 pages, 2 figures; v2. typos correcte

Highly selective detection of Hg2+ and MeHgI by di-pyridin-2-yl-[4-(2-pyridin-4-yl-vinyl)-phenyl]-amine and its zinc coordination polymer

©2016 the Partner Organisations. Solvothermal reaction of Zn(NO3)2·6H2O with di-pyridin-2-yl-[4-(2-pyridin-4-yl-vinyl)-phenyl]-amine (ppvppa) and 1,4-naphthalenedicarboxylic acid (1,4-H2NDC) in H2O and MeCN at 150 °C yielded a two-dimensional (2D) coordination Zn(ii) polymer [Zn(ppvppa)(1,4-NDC)]n (1). Compound 1 was characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction and thermogravimetric analysis. Compound 1 consists of dimeric [Zn2(ppvppa)2] units linked by 1,4-NDC bridges to generate a 2D honeycomb network. Either compound 1 or ppvppa alone can detect Hg2+ or MeHgI selectively and with good sensitivity. Upon addition of Hg2+ ions to a MeCN solution of ppvppa, marked changes in the UV-vis and fluorescence spectra are observed, associated with colour changes, which are easily identified by the naked eye. The pyridinyl rings of ppvppa are coordinated to the Hg2+ ion. This motif in the presence of NO3- ions forms a binuclear complex [Hg2(ppvppa)2(NO3)4] (2), which has been characterized as the solvate [Hg2(ppvppa)2(NO3)4]·H2O·4MeCN (2·H2O·4MeCN) by single-crystal X-ray diffraction studies. In aqueous solution, compound 1 emits pale orange light at ambient temperature and the addition of Hg2+ or MeHgI induces an change of fluorescence color from pale orange to blue. Compound 1 is a promising candidate as a sensitive naked-eye indicator for Hg2+ or MeHgI in water under a UV lamp. Introduction to the international collaboration Prof. Lang and Prof. Brammer met with each other in Nanjing, China when Prof. Brammer taught lectures at Nanjing Tech University last November. Prof. Lang's research involves metal sulfide cluster chemistry, design and development of new coordination complex-based catalysts, bioinorganic chemistry related to mimicking metal sites of enzymes and proteins, and so on. Prof. Brammer's research interest covers supramolecular chemistry and crystal engineering, in particular host-guest chemistry and catalysis in metal-organic frameworks, reactions in molecular solids and fundamentals of intermolecular interactions. Both professors recognised their many mutual research interests and decided to initiate an international collaborative project in the area of coordination polymers. Both will visit the partner's lab in China and UK in the near future and expand this project to a higher level

The Coupled Cluster Method in Hamiltonian Lattice Field Theory

The coupled cluster or exp S form of the eigenvalue problem for lattice Hamiltonian QCD (without quarks) is investigated. A new construction prescription is given for the calculation of the relevant coupled cluster matrix elements with respect to an orthogonal and independent loop space basis. The method avoids the explicit introduction of gauge group coupling coefficients by mapping the eigenvalue problem onto a suitable set of character functions, which allows a simplified procedure. Using appropriate group theoretical methods, we show that it is possible to set up the eigenvalue problem for eigenstates having arbitrary lattice momentum and lattice angular momentum.Comment: LaTeX, no figur

New Einstein-Sasaki and Einstein Spaces from Kerr-de Sitter

In this paper, which is an elaboration of our results in hep-th/0504225, we construct new Einstein-Sasaki spaces L^{p,q,r_1,...,r_{n-1}} in all odd dimensions D=2n+1\ge 5. They arise by taking certain BPS limits of the Euclideanised Kerr-de Sitter metrics. This yields local Einstein-Sasaki metrics of cohomogeneity n, with toric U(1)^{n+1} principal orbits, and n real non-trivial parameters. By studying the structure of the degenerate orbits we show that for appropriate choices of the parameters, characterised by the (n+1) coprime integers (p,q,r_1,...,r_{n-1}), the local metrics extend smoothly onto complete and non-singular compact Einstein-Sasaki manifolds L^{p,q,r_1,...,r_{n-1}}. We also construct new complete and non-singular compact Einstein spaces \Lambda^{p,q,r_1,...,r_n} in D=2n+1 that are not Sasakian, by choosing parameters appropriately in the Euclideanised Kerr-de Sitter metrics when no BPS limit is taken.Comment: latex, 26 page

1/4-BPS M-theory bubbles with SO(3) x SO(4) symmetry

In this paper we generalize the work of Lin, Lunin and Maldacena on the classification of 1/2-BPS M-theory solutions to a specific class of 1/4-BPS configurations. We are interested in the solutions of 11 dimensional supergravity with $SO(3)\times SO(4)$ symmetry, and it is shown that such solutions are constructed over a one-parameter familiy of 4 dimensional almost Calabi-Yau spaces. Through analytic continuations we can obtain M-theory solutions having $AdS_2\times S^3$ or $AdS_3\times S^2$ factors. It is shown that our result is equivalent to the $AdS$ solutions which have been recently reported as the near-horizon geometry of M2 or M5-branes wrapped on 2 or 4-cycles in Calabi-Yau threefolds. We also discuss the hierarchy of M-theory bubbles with different number of supersymmetries.Comment: 22 pages, JHEP3.cls; v2. revised version. showed that our results agree with previous works hep-th/0605146 and hep-th/061219

Sequestered Dark Matter

We show that hidden-sector dark matter is a generic feature of the type IIB string theory landscape and that its lifetime may allow for a discovery through the observation of very energetic gamma-rays produced in the decay. Throats or, equivalently, conformally sequestered hidden sectors are common in flux compactifications and the energy deposited in these sectors can be calculated if the reheating temperature of the standard model sector is known. Assuming that throats with various warp factors are available in the compact manifold, we determine which throats maximize the late-time abundance of sequestered dark matter. For such throats, this abundance agrees with cosmological data if the standard model reheating temperature was 10^10 - 10^11 GeV. In two distinct scenarios, the mass of dark matter particles, i.e. the IR scale of the throat, is either around 10^5 GeV or around 10^10 GeV. The lifetime and the decay channels of our dark matter candidates depend crucially on the fact that the Klebanov-Strassler throat is supersymmetric. Furthermore, the details of supersymmetry breaking both in the throat and in the visible sector play an essential role. We identify a number of scenarios where this type of dark matter can be discovered via gamma-ray observations.Comment: 36 pages, 3 figures; v2: references added, v3: introduction extended and typos correcte

Coupling of thermal and mass diffusion in regular binary thermal lattice-gases

We have constructed a regular binary thermal lattice-gas in which the thermal diffusion and mass diffusion are coupled and form two nonpropagating diffusive modes. The power spectrum is shown to be similar in structure as for the one in real fluids, in which the central peak becomes a combination of coupled entropy and concentration contributions. Our theoretical findings for the power spectra are confirmed by computer simulations performed on this model.Comment: 5 pages including 3 figures in RevTex

Superlattice Patterns in Surface Waves

We report novel superlattice wave patterns at the interface of a fluid layer driven vertically. These patterns are described most naturally in terms of two interacting hexagonal sublattices. Two frequency forcing at very large aspect ratio is utilized in this work. A superlattice pattern ("superlattice-I") consisting of two hexagonal lattices oriented at a relative angle of 22^o is obtained with a 6:7 ratio of forcing frequencies. Several theoretical approaches that may be useful in understanding this pattern have been proposed. In another example, the waves are fully described by two superimposed hexagonal lattices with a wavelength ratio of sqrt(3), oriented at a relative angle of 30^o. The time dependence of this "superlattice-II" wave pattern is unusual. The instantaneous patterns reveal a time-periodic stripe modulation that breaks the 6-fold symmetry at any instant, but the stripes are absent in the time average. The instantaneous patterns are not simply amplitude modulations of the primary standing wave. A transition from the superlattice-II state to a 12-fold quasi-crystalline pattern is observed by changing the relative phase of the two forcing frequencies. Phase diagrams of the observed patterns (including superlattices, quasicrystalline patterns, ordinary hexagons, and squares) are obtained as a function of the amplitudes and relative phases of the driving accelerations.Comment: 15 pages, 14 figures (gif), to appear in Physica