Symmetry of superconducting states with two orbitals on a tetragonal lattice: application to LaO1−xFxFeAsLaO_{1-x}F_{x}FeAs

We use group theory to classify the superconducting states of systems with two orbitals on a tetragonal lattice. The orbital part of the superconducting gap function can be either symmetric or anti-symmetric. For the orbital symmetric state, the parity is even for spin singlet and odd for spin triplet; for the orbital anti-symmetric state, the parity is odd for spin singlet and even for spin triplet. The gap basis functions are obtained with the use of the group chain scheme by taking into account the spin-orbit coupling. In the weak pairing limit, the orbital anti-symmetric state is only stable for the degenerate orbitals. Possible application to iron-based superconductivity is discussed.Comment: published versio

Risk assessment of the transfer of imazethapyr herbicide resistance from Clearfield rice to red rice

Potential outcrossing between Clearfield rice and red rice will have a direct impact on the management and long-term usefulness of imazethapyr technology for rice weed control. The principal objective of this research was to determine the rate and agronomic consequences for outcrossing between Clearfield rice and red rice in south Louisiana. Collection and analysis of red rice samples across two years and 24 commercial locations indicated that red rice infestation after imazethapyr application differed substantially at different Clearfield locations. Straw hull and awnless red rice was the principal biotype observed for both years. Red rice populations possessed extensive variation for agronomic traits such as plant height, panicle length, tillers/plant, seeds/plant, seed set and grain weight. Outcrossing occurred from all Clearfield rice varieties (¡®CL121¡¯, ¡®CL141¡¯ and ¡®CL161¡¯) to red rice. An average outcrossing frequency of 0.163% was observed in red rice samples collected in 2002 with a range of 0.017% to 0.583%. A four-fold increase in outcrossing frequency of 0.679% was found in red rice samples collected in 2003 with two locations exhibiting outcrossing \u3e 1%. Outcrossing frequency did not correlate with any agronomic trait from the red rice samples across two years. Imazethapyr resistance was generally controlled by a single dominant gene, except in some F2 populations where significant deviations from expected resistant/susceptible ratios were detected. Similar results were observed in F2 populations for segregation of pubescent/glabrous leaves. F1 hybrids between Clearfield rice and red rice in general did not show increased fitness in flowering characteristics over Clearfield rice, as most hybrids did not flower or produce seeds in the field. However, increased fitness in F1 hybrids, derived from red rice samples collected in 2002, was detected over Clearfield rice for plant height, tillers/plant, and panicles/plant. Enhanced fitness in F1 hybrids from red rice samples collected in 2003 over Clearfield rice was exhibited for plant height, panicle length, spikelets/panicle, and panicles/plant. Results from this study indicate that outcrossing between Clearfield and red rice will occur rapidly at rates that warrant early-season field scouting and a rotation scheme for Clearfield rice to prolong usefulness of the imazethapyr technology

Software for Wearable Devices: Challenges and Opportunities

Wearable devices are a new form of mobile computer system that provides exclusive and user-personalized services. Wearable devices bring new issues and challenges to computer science and technology. This paper summarizes the development process and the categories of wearable devices. In addition, we present new key issues arising in aspects of wearable devices, including operating systems, database management system, network communication protocol, application development platform, privacy and security, energy consumption, human-computer interaction, software engineering, and big data.Comment: 6 pages, 1 figure, for Compsac 201

NMR evidence of strong-correlated superconductivity in LiFeAs: tuning toward an SDW ordering

In this letter, we reported the results of NMR study on LiFeAs single crystals. We find a strong evidence of the low temperature spin fluctuations; by changing sample preparation conditions, the system can be tuned toward an spin-density-wave (SDW) quantum-critical point. The detection of an interstitial Li(2) ion, possibly locating in the tetrahedral hole, suggests that the off-stoichiometry and/or lattice defect can probably account for the absence of the SDW ordering in LiFeAs. These facts show that LiFeAs is a strongly correlated system and the superconductivity is likely originated from the SDW fluctuations.Comment: 5 pages, s figure

In-plane noncollinear exchange coupling mediated by helical edge states in Quantum Spin Hall system

We study the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction mediated by helical edge states in quantum spin hall system. The helical edge states induce an in-plane noncollinear exchange coupling between two local spins, in contrast to the isotropic coupling induced in normal metal. The angle between the two local spins in the ground state depends on the Fermi level. This property may be used to control the angle of spins by tuning the electric gate.Comment: 4 pages, 1 figur

Global phase diagram of three-dimensional extended Boson Hubbard model - a continuous time Quantum Monte Carlo study

We present the global phase diagram of the extended boson Hubbard model on a simple cubic lattice by quantum Monte Carlo simulation with worm update algorithm. Four kinds of phases are supported by this model, including superfluid, supersolid, Mott, and charge density wave (CDW) states, which are identified in the phase diagram of chemical potential $\mu$ versus nearest neighbor interaction V . By changing the chemical potential, a continuous transition is found from the Mott phase to a superfluid phase without breaking the translational symmetry. For an insulating CDW state, adding particles to it gives rise to a continuous transition to a supersolid phase, while removing particles usually leads to a first-order one to either supersolid or superfluid phase. By tuning the nearest neighbor interaction, one can realize the transition between two insulating phases, Mott and CDW with the same particle density, which turns out to be of the first-order. We also demonstrate that a supersolid phase with average particle density less than 1/2 can exist in a small region of $\mu$ - V phase diagram