218 research outputs found

    Characteristic length of a Holographic Superconductor with dd-wave gap

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    After the discovery of the ss-wave and pp-wave holographic superconductors, holographic models of dd-wave superconductor have also been constructed recently. We study analytically the perturbation of the dual gravity theory to calculate the superconducting coherence length ξ\xi of the dd-wave holographic superconductor near the superconducting phase transition point. The superconducting coherence length ξ\xi divergents as (1T/Tc)1/2(1-T/T_c)^{-1/2} near the critical temperature TcT_c. We also obtain the magnetic penetration depth λ(TcT)1/2\lambda\propto(T_c-T)^{-1/2} by adding a small external homogeneous magnetic field. The results agree with the ss-wave and pp-wave models, which are also the same as the Ginzburg-Landau theory.Comment: last version, 10 pages, accepted by PR

    d-wave Holographic Superconductor Vortex Lattice and Non-Abelian Holographic Superconductor Droplet

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    A d-wave holographic superconductor is studied under a constant magnetic field by perturbation method, we obtain both droplet and triangular vortex lattice solution. The results are the same as the s-wave holographic superconductor. The non-Abelian holographic superconductor with p+ipp+ip-wave background is also studied under magnetic field, unlike the d-wave and s-wave models, we find that the non-Abelian model has only droplet solution.Comment: Version2, 12 pages,2 figures. Accepted by PR

    Supercurrent in p-wave Holographic Superconductor

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    The p-wave and p+ipp+ip-wave holographic superconductors with fixed DC supercurrent are studied by introducing a non-vanishing vector potential. We find that close to the critical temperature TcT_c of zero current, the numerical results of both the p wave model and the p+ipp+ip model are the same as those of Ginzburg-Landau (G-L) theory, for example, the critical current jc(TcT)3/2j_c \sim (T_c-T)^{3/2} and the phase transition in the presence of a DC current is a first order transition. Besides the similar results between both models, the p+ipp+ip superconductor shows isotropic behavior for the supercurrent, while the p-wave superconductor shows anisotropic behavior for the supercurrent.Comment: Version 4. 18 pages, 9figures. New results of the anisotropic behavior for the supercurrent in p-wave model added. Accepted by PR

    A STUDY ON THE EXTRACTION PROCESS OF ACTIVE INGREDIENTS FROM AKEBIA STEM AND AN ANALYSIS OF THEIR ANTI-GASTRIC CANCER ACTIVITY

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    The study investigated the extraction process of active ingredients from akebia stem and an analysis of their anti-gastric cancer activity. Three different extraction methods were used to obtain extracts, namely the decoction method (group A), reflux extraction method (group B), and maceration method (group C), of which reflux extraction method and maceration method used ethanol as the extraction solvent, while decoction method used distilled water for extraction. The differences in anti-gastric cancer activity of the three extracts were compared. MTT assay was used to test and compare the inhibitory effects of extracts obtained in A, B, and C groups on gastric cancer cells. The results showed that the dry extract obtained by heat reflux extraction with “water-ethanol” ratio of 1:2, extractant volume of 70 ml, with ethanol as extraction solvent presented the best inhibitory activity on gastric cancer SGC-7901 cells in this study. Its inhibitory effect did not change over time, and was directly proportional to the concentration

    Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

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    Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30MM_{\odot} for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
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