Nuclear Magnetic Relaxation Rate in a Noncentrosymmetric Superconductor

For a noncentrosymmetric superconductor such as CePt3Si, we consider a Cooper pairing model with a two-component order parameter composed of spin-singlet and spin-triplet pairing components. We demonstrate that such a model on a qualitative level accounts for experimentally observed features of the temperature dependence of the nuclear spin-lattice relaxation rate 1/T1, namely a peak just below Tc and a line-node gap behavior at low temperatures.Comment: 4 page

Detecção de Potyvirus em bucha (Luffa cylindrica (L.) Roem.) no estado do Pará.

A bucha (Luffa cyllindrica (L.) Roem.) é uma trepadeira da família das cucurbitáceas cultivada especialmente pelas fibras do fruto seco, que tem vários usos principalmente como esfregão de banho. Folhas de plantas apresentando mosaico amarelo no município de Baião foram coletadas levadas para proceder a diagnose no laboratório de fitopatologia da Embrapa Amazônia Oriental. Para a identificação do vírus foi realizado o teste sorológico PTA-ELISA onde se testou a amostra da bucha contra os antissoros específicos para Cucumber mosaic virus (CMV), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV) e Squash mosaic virus (SMV). Extrato da folha da bucha com mosaico reagiu positivamente com o antissoro do ZYMV indicando se tratar de potyvirus. Assim, a comprovação de que o mosaico da bucha é causado por potyvirus foi feita via RT-PCR utilizando primers específico para o gênero. Além da sorologia foi realizada a purificação parcial do vírus, extração de RNA viral seguido do RT-PCR onde utilizou o par de primers universal (WCIEN e PV1) para espécies virais do gênero Potyvirus. Após eletroforese para análise do produto da RT-PCR observou-se a presença do fragmento de DNA do tamanho esperado de aproximadamente 800 pb confirmando a presença de potyvirus. Plantas de bucha infectadas podem servir de fonte de inóculo para outras plantas cultivadas como abóbora e pepin

Identificação de Cucumber mosaic virus em pimenta no estado do Pará.

A pimenta (Capsicum chinense e C. frutescens) é bastante cultivada no estado do Pará, mas algumas doenças podem limitar sua produção. É comum observar plantas com sintomas de viroses. Assim, este trabalho tem o objetivo de identificar os vírus que ocorrem em plantios de pimenta. Foram coletadas amostras de plantios no município de Santa Izabel e em Belém. Para isso, foi realizada a inoculação em plantas indicadoras, extração de acido nucleico, os testes de RT-PCR e sequenciamento nucleotídico. Foram analisadas quatro amostras provenientes de Santa Izabel e duas de Belém. Os isolados virais foram transmitidos mecanicamente para plantas indicadoras de vírus Nicotiana tabacco cv. TNN e N. tabacum cv. Turkish que apresentaram mosaico foliar. A partir de folhas infectadas de fumo foi feita a extração do ácido nucléico total. Posteriormente, foi feito o teste de RT-PCR, utilizando os pares de primers CMV-CPR e CMV-CPF para detecção de Cucumber mosaic virus ? CMV e PV1 e WCIEN para espécies do gênero Potyvirus. As amostras foram positivas para o CMV, pois amplificaram o gene da capa proteica de aproximadamente 700pb. O produto PCR de dois isolados (Belém e Santa Izabel) foram sequenciados e analisados utilizando os programas Blast e ClustalW. Os dois isolados apresentaram identidade de aminoácido de 98% quando comparados com acessos disponíveis no GenBank. Este foi o primeiro relato de Cucumber mosaic virus no estado do Pará. Até o momento foi identificado apenas o CMV em pimentais no Pará, sendo este considerado um dos principais vírus relatados no Brasil no gênero Capsicum sp

Positions of Point-Nodes in Borocarbide Superconductor YNi2B2C

To determine the superconducting gap function of YNi2B2C, we calculate the local density of states (LDOS) around a single vortex core with the use of Eilenberger theory and the band structure calculated by local density approximation assuming various gap structures with point-nodes at different positions. We also calculate the angular-dependent heat capacity in the vortex state on the basis of the Doppler-Shift method. Comparing our results with the STM/STS experiment, the angular-dependent heat capacity and thermal conductivity, we propose the gap-structure of YNi2B2C, which has the point-nodes and gap minima along . Our gap-structure is consistent with all results of angular-resolved experiments.Comment: 7 pages, 5 figure

Surface and vortex structures in noncentrosymmetric superconductors under applied magnetic fields

We investigate how the macroscopic spatial structure of broken inversion symmetry manifests in noncentrosymmetric superconductors, by the microscopic broken inversion symmetry of the crystal structure. Based on the time-dependent Ginzburg-Landau theory including the Pauli paramagnetic effect and the Rashba interaction, we demonstrate that the centrosymmetric structures of the internal field and the screening current are broken macroscopically. The flow structure of paramagnetic supercurrent spontaneously induce the flux flow without applying external currents.Comment: 5 pages, 8 figures. accepted in Phys. Rev.

Nonuniform Spin Triplet Superconductivity due to Antisymmetric Spin-Orbit Coupling in Noncentrosymmetric Superconductor CePt3_3Si

We show that the nonuniform state (Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state) of the spin triplet superconductivity in noncentrosymmetric systems is stabilized by antisymmetric spin-orbit coupling even if the magnetic field is absent. The transition temperature of the spin triplet superconductivity is reduced by the antisymmetric spin-orbit coupling in general. This pair breaking effect is shown to be similar to the Pauli pair breaking effect due to magnetic field for the spin singlet superconductivity, in which FFLO state is stabilized near the Pauli limit (or Chandrasekhar-Clogston limit) of external magnetic field. Since there are gapless excitations in nonuniform superconducting state, some physical quantities such as specific heat and penetration depth should obey the power low temperature-dependences. We discuss the possibility of the realization of nonuniform state in CePt$_3$Si.Comment: 8 pages, 6 figure

Locally Weyl invariant massless bosonic and fermionic spin-1/2 action in the (Wn(4),g)\bf (W_{n(4)},g) and (U4,g)\bf (U_{4},g) space-times

We search for a real bosonic and fermionic action in four dimensions which both remain invariant under local Weyl transformations in the presence of non-metricity and contortion tensor. In the presence of the non-metricity tensor the investigation is extended to Weyl $(W_n, g)$ space-time while when the torsion is encountered we are restricted to the Riemann-Cartan $(U_4, g)$ space-time. Our results hold for a subgroup of the Weyl-Cartan $(Y_4, g)$ space-time and we also calculate extra contributions to the conformal gravity.Comment: 16 page

Analytical Formulation of the Local Density of States around a Vortex Core in Unconventional Superconductors

On the basis of the quasiclassical theory of superconductivity, we obtain a formula for the local density of states (LDOS) around a vortex core of superconductors with anisotropic pair-potential and Fermi surface in arbitrary directions of magnetic fields. Earlier results on the LDOS of d-wave superconductors and NbSe$_2$ are naturally interpreted within our theory geometrically; the region with high intensity of the LDOS observed in numerical calculations turns out to the enveloping curve of the trajectory of Andreev bound states. We discuss experimental results on YNi$_2$B$_2$C within the quasiclassical theory of superconductivity.Comment: 13 pages, 16 figure

Ds0*(2317) and Ds1(2460) mesons in two-body B-meson decays

We analyze the branching ratios of B to D(*) + Ds0*(Ds1) decays using the factorization hypothesis. The B to D(*) transition form factors are taken from a model-independent analysis done by Caprini, Lellouch and Neubert based on heavy quark spin symmetry and dispersive constraints, including short-distance and power corrections. The leptonic decay constants fDs0* and fDs1 are calculated assuming a molecular structure for the Ds0* and Ds1 mesons. The calculated branching ratios of B-meson two-body decays are compared with experimental data and other theoretical results.Comment: 12 pages, 2 figure

The quantum Chernoff bound as a measure of distinguishability between density matrices: application to qubit and Gaussian states

Hypothesis testing is a fundamental issue in statistical inference and has been a crucial element in the development of information sciences. The Chernoff bound gives the minimal Bayesian error probability when discriminating two hypotheses given a large number of observations. Recently the combined work of Audenaert et al. [Phys. Rev. Lett. 98, 160501] and Nussbaum and Szkola [quant-ph/0607216] has proved the quantum analog of this bound, which applies when the hypotheses correspond to two quantum states. Based on the quantum Chernoff bound, we define a physically meaningful distinguishability measure and its corresponding metric in the space of states; the latter is shown to coincide with the Wigner-Yanase metric. Along the same lines, we define a second, more easily implementable, distinguishability measure based on the error probability of discrimination when the same local measurement is performed on every copy. We study some general properties of these measures, including the probability distribution of density matrices, defined via the volume element induced by the metric, and illustrate their use in the paradigmatic cases of qubits and Gaussian infinite-dimensional states.Comment: 16 page