KKbar molecules with momentum-dependent interactions

It is shown that the momentum-dependent kaon-antikaon interactions generated via vector meson exchange from the standard SU_V(3) x SU_A(3) interaction Lagrangian lead to a non-local potential in coordinate space that can be incorporated without approximation into a non-relativistic version of the Bethe-Salpeter wave equation containing a radial-dependent effective kaon mass appearing in a fully symmetrized kinetic energy operator, in addition to a local potential. Estimates of the mass and decay widths of f_0(980) and a_0(980), considered as KKbar molecules of isospin 0 and 1, as well as for K^+K^- atomic bound states (kaonium) are presented, and compared with previous studies of a similar nature. It is argued that without a better knowledge of hadronic form factors it is not possible to distinguish between the molecular versus elementary particle models for the structure of the light scalar mesons.Comment: 14 pages, 2 tables, 5 figures. Added subsection on s-channel exchange, additional remarks on the possible effect of gluon exchange, and 1 additional figur

Multi-qubit gate with trapped ions for microwave and laser-based implementation

A proposal for a phase gate and a Mølmer–Sørensen gate in the dressed state basis is presented. In order to perform the multi-qubit interaction, a strong magnetic field gradient is required to couple the phonon-bus to the qubit states. The gate is performed using resonant microwave driving fields together with either a radio-frequency (RF) driving field, or additional detuned microwave driving fields. The gate is robust to ambient magnetic field fluctuations due to an applied resonant microwave driving field. Furthermore, the gate is robust to fluctuations in the microwave Rabi frequency and is decoupled from phonon dephasing due to a resonant RF or a detuned microwave driving field. This makes this new gate an attractive candidate for the implementation of high-fidelity microwave based multi-qubit gates. The proposal can also be realized in laser-based set-ups

A unification in the theory of linearization of second order nonlinear ordinary differential equations

In this letter, we introduce a new generalized linearizing transformation (GLT) for second order nonlinear ordinary differential equations (SNODEs). The well known invertible point (IPT) and non-point transformations (NPT) can be derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be linearized through NPT and IPT can be linearized by this GLT. We also illustrate how to construct GLTs and to identify the form of the linearizable equations and propose a procedure to derive the general solution from this GLT for the SNODEs. We demonstrate the theory with two examples which are of contemporary interest.Comment: 8 page

A digitally printed optoelectronic nose for the selective trace detection of nitroaromatic explosive vapours using fluorescence quenching

We report on a fluorescent optoelectronic nose for the trace detection of nitroaromatic explosive vapours. The sensor arrays, fabricated by aerosol-jet printing, consist of six different commercially available polymers as transducers. We assess the within-batch reproducibility of the printing process and we report that the sensor polymers show efficient fluorescence quenching capabilities with detection limits of a few parts-per-billion in air. We further demonstrate the nose\u27s ability to discriminate between several nitroaromatics including nitrobenzene, 1,3-dinitrobenzene and 2,4-dinitrotoluene at three different concentrations using linear discriminant analysis. Our approach enables the realization of highly integrated optical sensor arrays in optoelectronic noses for the sensitive and selective detection of nitroaromatic explosive trace vapours using a potentially low-cost digital printing technique suitable for high-volume fabrication

Geometry of General Hypersurfaces in Spacetime: Junction Conditions

We study imbedded hypersurfaces in spacetime whose causal character is allowed to change from point to point. Inherited geometrical structures on these hypersurfaces are defined by two methods: first, the standard rigged connection induced by a rigging vector (a vector not tangent to the hypersurface anywhere); and a second, more physically adapted, where each observer in spacetime induces a new type of connection that we call the rigged metric connection. The generalisation of the Gauss and Codazzi equations are also given. With the above machinery, we attack the problem of matching two spacetimes across a general hypersurface. It is seen that the preliminary junction conditions allowing for the correct definition of Einstein's equations in the distributional sense reduce to the requirement that the first fundamental form of the hypersurface be continuous. The Bianchi identities are then proven to hold in the distributional sense. Next, we find the proper junction conditions which forbid the appearance of singular parts in the curvature. Finally, we derive the physical implications of the junction conditions: only six independent discontinuities of the Riemann tensor are allowed. These are six matter discontinuities at non-null points of the hypersurface. For null points, the existence of two arbitrary discontinuities of the Weyl tensor (together with four in the matter tensor) are also allowed.Comment: Latex, no figure

Primary Oral Tuberculosis as an Indicator of HIV Infection

We present a case of primary oral tuberculosis that led to the diagnosis of HIV infection. Our patient had clinically nonspecific ulcers on the labial mucosa and on the ventral surface of the tongue which were diagnosed as being tuberculous only on histological examination. This raised the suspicion of HIV infection that was subsequently confirmed by blood tests. The oral lesions resolved after 4 weeks of antituberculosis treatment. Some aspects of the pathogenesis of HIV-tuberculosis coinfection are discussed

Polarization-Sensitive Photodetectors Based on Directionally Oriented Organic Bulk-Heterojunctions

Polarized spectroscopic photodetection enables numerous applications in diverse areas such as sensing, industrial quality control, and visible light communications. Although organic photodetectors (OPDs) can offer a cost-effective alternative to silicon-based technology—particularly when flexibility and large-area arrays are desired—polarized OPDs are only beginning to receive due research interest. Instead of resorting to external polarization optics, this report presents polarized OPDs based on directionally oriented blends of poly(3-hexylthiophene) (P3HT) and benchmark polymer or nonfullerene acceptors fabricated using a versatile solution-based method. Furthermore, a novel postprocessing scheme based on backfilling and plasma etching is advanced to ameliorate high dark-currents that are otherwise inherent to fibrillar active layers. The resulting polarized P3HT:N2200 OPDs exhibit a broad enhancement across all principal figures of merit compared to reference isotropic devices, including peak responsivities of 70 mA W$^{-1}$ and up to a threefold increase in 3 dB bandwidth to 0.75 MHz under parallel-polarized illumination. Polarization ratios of up to 3.5 are obtained across a spectral range that is determined by the specific donor–acceptor combinations. Finally, as a proof-of-concept demonstration, polarized OPDs are used for photoelasticity analysis of rubber films under tensile deformation, highlighting their potential for existing and emerging applications in advanced optical sensing

Fabrication and evaluation of a nickel shim for large-area hot embossing of plant surface structures

Petal textures exhibit outstanding broadband and omnidirectional light harvesting properties on solar cells [1,2] + by choice of low surface energy materials their self-cleaning properties can be harnessed [3]. A hot embossing routine via robust nickel embossing tools has been developed for a large area fabrication of such textures