Massive Dirac fermions and spin physics in an ultrathin film of topological insulator

We study transport and optical properties of the surface states which lie in the bulk energy gap of a thin-film topological insulator. When the film thickness is comparable with the surface state decay length into the bulk, the tunneling between the top and bottom surfaces opens an energy gap and form two degenerate massive Dirac hyperbolas. Spin dependent physics emerges in the surface bands which are vastly different from the bulk behavior. These include the surface spin Hall effects, spin dependent orbital magnetic moment, and spin dependent optical transition selection rule which allows optical spin injection. We show a topological quantum phase transition where the Chern number of the surface bands changes when varying the thickness of the thin film.Comment: 7 pages, 5 figure

SiGeSn laser diodes and method of fabricating same

Description and specifications of a new and distinct cultivar of blackberry plant named ‘APF-404T’ which originated from seed produced by a hand-pollinated cross of Arkansas selections ‘APF-185T’ (a non-patented, unreleased breeding selection) x ‘A-2444T’ (a non-patented, unreleased breeding selection) is provided. This new cultivar of blackberry plant can be distinguished by its thornless canes, primocane-fruiting tendency, and large, sweet fruit. The plants have consistently good plant health and produce fruit suitable for home gardens

Pion condensation in dense QCD, the dilute Bose gas, and speedy Goldstone bosons

We consider pion condensation in cold and dense QCD using chiral perturbation theory ($\chi$PT). Thermodynamic quantities are calculated at next-to-leading order in the low-energy expansion. In the nonrelatistivtic limit, we recover the classic result by Lee and Yang for the energy density of a dilute Bose gas with an $s$-wave scattering length that includes loop corrections from $\chi$PT. In the chiral limit, we calculate the thermodynamic functions to next-to-leading order in the low-energy expansion. We use Son's prescription to write down an effective field theory for the massless Goldstone boson that results from the spontaneous breakdown of the global internal symmetry $U(1)_{I_3}$ at finite isospin density $n_I$. In the ultrarelativistic limit, the phonons propagate with the speed of light up to renormalization effects. The damping rate of the phonons behaves as $p^5$ for small momenta in agreement with Beliaev's old result for a weakly interacting Bose gas.Comment: 11 pages, one figure. V2: few typos fixed and added reference

SiGeSn laser diodes and method of fabricating same

Description and specifications of a new and distinct cultivar of blackberry plant named ‘APF-404T’ which originated from seed produced by a hand-pollinated cross of Arkansas selections ‘APF-185T’ (a non-patented, unreleased breeding selection) x ‘A-2444T’ (a non-patented, unreleased breeding selection) is provided. This new cultivar of blackberry plant can be distinguished by its thornless canes, primocane-fruiting tendency, and large, sweet fruit. The plants have consistently good plant health and produce fruit suitable for home gardens