Ginzburg-Landau Equations for Coexistent States of Superconductivity and Antiferromagnetism in t-J model

Ginzburg-Landau (GL) equations for the coexistent state of superconductivity and antiferromagnetism are derived microscopically from the t-J model with extended transfer integrals. GL equations and the GL free energy, which are obtained based on the slave-boson mean-field approximation, reflect the electronic structure of the microscopic model, especially the evolution of the Fermi surface due to the change of the doping rate. Thus they are suitable for studying the material dependence of the coexistent states in high-$T_C$ cuprate superconductors.Comment: 12 page

Shallow and diffuse spin-orbit potential for proton elastic scattering from neutron-rich helium isotopes at 71 MeV/nucleon

Vector analyzing powers for proton elastic scattering from 8He at 71 MeV/nucleon have been measured using a solid polarized proton target operated in a low magnetic field of 0.1 T. The spin-orbit potential obtained from a phenomenological optical model analysis is found to be significantly shallower and more diffuse than the global systematics of stable nuclei, which is an indication that the spin-orbit potential is modified for scattering involving neutron-rich nuclei. A close similarity between the matter radius and the root-mean-square radius of the spin-orbit potential is also identified.Comment: 6 pages, 4 figures, accepted for publication in Physical Review C Rapid Communicatio

Precision measurement of vector and tensor analyzing powers in elastic deuteron-proton scattering

High precision vector and tensor analyzing powers of elastic deuteron-proton d+p scattering have been measured at intermediate energies to investigate effects of three-nucleon forces (3NF). Angular distribution in the range of 70-120 degree in the center-of mass frame for incident-deuteron energies of 130 and 180 MeV were obtained using the RIKEN facility. The beam polarization was unambiguously determined by measuring the 12C(d,alpha)10B(2+) reaction at 0 degree. Results of the measurements are compared with state-of-the-art three-nucleon calculations. The present modeling of nucleon-nucleon forces and its extension to the three-nucleon system is not sufficient to describe the high precision data consistently and requires, therefore, further investigation

Geometrically Frustrated Crystals: Elastic Theory and Dislocations

Elastic theory of ring-(or cylinder-)shaped crystals is constructed and the generation of edge dislocations due to geometrical frustration caused by the bending is studied. The analogy to superconducting (or superfluid) vortex state is pointed out and the phase diagram of the ring-crystal, which depends on radius and thickness, is discussed.Comment: 4 pages, 3 figure

Phase diagram and critical properties of the frustrated Kondo necklace model in a magnetic field

The critical properties of the frustrated Kondo necklace model with a half saturation magnetization ($m=1/2$) have been studied by means of an exact-diagonalization method. It is shown from bosonization technique that the model can be effectively expressed as a quantum sine-Gordom model. Thus it may show three (dimer plateau, N{\'e}el plateau and Tomonaga-Luttinger liquid) phases due to competitions among the Ising anisotropy $\Delta$, and the nearest- and next-nearest-neighbor exchange interactions $J_1$ and $J_2$. The boundary lines on the $\Delta-J_2/J_1$ phase diagram separating the three phases are determined by the method of level spectroscopy based on the conformal field theory.Comment: 5 pages, 5 figure

Effect of spin-orbit impurity scattering in the superconducting state of t-J model

We study the effect of magnetic impurities in the d_{x^2-y^2}-wave superconducting (SC) state of the two dimensional t-J model.The spin-orbit and the spin-exchange interactions are examined by treating the impurity as a classical spin. The Bogoliubov de Gennes equation derived within a slave-boson mean-field approximation is solved numerically at T = 0. The spin-exchange scattering induces spin-triplet p-wave SC order parameters near the impurity, while a SC state with broken time-reversal symmetry and a spontaneous current appears in the presence of the spin-orbit interaction. When both interactions coexist, it turns out that a state which carries a spontaneous spin current occurs.Comment: 4 pages, 7 figure

g-on Mean Field Theory of the t-J Model

Implication of our recent proposal [J. Phys. Soc. Jpn. 65 (1996) 687] to treat large-amplitude gauge-field fluctuations around the slave-boson mean-field theory for the t-J model has been explored in detail. By attaching gauge flux to spinons and holons and then treating them as free g-on's which respect the time-reversal symmetry, the optimum exclusion (g) and exchange (\a) statistics have been determined in the plane of doping rate and temperature. Two different relations between \a and g have been investigated, namely g=|\a| (Case1) and g=|\a|(2-|\a|) (Case2). The results indicate that slave fermion is favored at low doping while slave boson at high doping. For two dimension, in Case1 intermediate statistics are found in between, while in Case2 no intermediate statistics are found. The consequences of varying the dimensionality and strength of J have been studied also. The latter has no qualitative effect for both cases, while the former has a profound effect in Case1.Comment: 18 pages, 11 figures two of them are figure 8; submitted to Phys. Rev. B; notes and citations are added, as seen in page 17; E-mails: [email protected], [email protected]

A new initiative for the development of new diagnostic tests for human African trypanosomiasis

Human African trypanosomiasis is a threat to millions of people living in sub-Saharan countries and is fatal unless treated. At present, the serological and parasitological tests used in the field for diagnosis of sleeping sickness have low specificity and sensitivity. There is clearly an urgent need for accurate tools for both diagnosis and staging of the disease. The Foundation for Innovative New Diagnostics and the World Health Organization have announced that they will collaborate to develop and evaluate new diagnostic tests for human African trypanosomiasis

Spectroscopy of 32Ne and the Island of Inversion

We report on the first spectroscopic study of the N=22 nucleus 32Ne at the newly completed RIKEN Radioactive Ion Beam Factory. A single gamma-ray line with an energy of 722(9) keV was observed in both inelastic scattering of a 226 MeV/u 32Ne beam on a Carbon target and proton removal from 33Na at 245 MeV/u. This transition is assigned to the de-excitation of the first J^pi = 2+ state in 32Ne to the 0+ ground state. Interpreted through comparison with state-of-the-art shell model calculations, the low excitation energy demonstrates that the Island of Inversion extends to at least N=22 for the Ne isotopes.Comment: Accepted for publication in Phys. Rev. Lett. 11 pages, 3 figure

Development of a LAMP assay for detection of Leishmania infantum infection in dogs using conjunctival swab samples

Background: Leishmania infantum infections in dogs play a crucial role in the transmission of pathogens causing visceral leishmaniasis to humans in the Gansu province, northwest China. To be able to control zoonotic transmission of the parasite to humans, a non-invasive loop-mediated isothermal amplification (LAMP) assay to specifically detect L. infantum infections in dogs was developed. Methods: The primers used in the LAMP assay were designed to target kinetoplast DNA minicircle sequences of the L. infantum isolate MCAN/CN/90/SC and tested using DNA isolated from promastigotes of different Leishmania species. The LAMP assay was evaluated with conjunctional swab samples obtained from 111 and 33 dogs living in an endemic and a non-endemic region of zoonotic visceral leishmaniasis in the Gansu province, respectively. The LAMP assay was also compared with conventional PCR, ELISA and microscopy using conjunctional swab, serum and bone marrow samples from the dogs, respectively. Results: The LAMP assay detected 1 fg of L. infantum DNA purified from cultured promastigotes which was 10-fold more sensitive than a conventional PCR test using Leishmania genus-specific primers. No cross reaction was observed with DNA isolated from promastigotes of L. donovani, L. major, L. tropica, and L. braziliensis, and the L. infantum reference strain MHOM/TN/80/IPT1. The L. infantum-positive rates obtained for field-collected samples were 61.3%, 58.6%, 40.5% and 10.8% by LAMP, PCR, ELISA and microscopy, respectively. As only one out of the 33 samples from control dogs from the non-endemic region of zoonotic visceral leishmaniasis was positive by the LAMP assay and the PCR test, the observed true negative rate (specificity) was 97% for both methods. Conclusion: This study has shown that the non-invasive, conjunctional swab-based LAMP assay developed was more sensitive in the detection of leishmaniasis in dogs than PCR, ELISA and microscopy. The findings indicate that the LAMP assay is a sensitive and specific method for the field surveillance of domestic dogs, particularly of asymptomatic canines, in ZVL-endemic areas in western China