Nonlinear response and scaling law in the vortex state of d-wave superconductors

We study the field dependence of the quasi-particle density of states, the thermodynamics and the transport properties in the vortex state of d-wave superconductors when a magnetic field is applied perpendicular to the conducting plane, specially for the low field and the low temperature compared to the upper critical field and transition temperature, respectively, $H/H_{c2} \ll 1$ and $T/T_c \ll 1$. Both the superfluid density and the spin susceptibility exhibit the characteristic $\sqrt{H}$-field dependence, while the nuclear spin lattice relaxation rate T$_1^{-1}$ and the thermal conductivity are linear in field $H$. With increasing temperature, these quantities exhibit the scaling behavior in $T/\sqrt{H}$. The present theory applies to 2D $f$-wave superconductor as well; a possible candidate of the superconductivity in Sr$_2$RuO$_4$.Comment: 11 pages, 4 figure

Low-lying excitations around a single vortex in a d-wave superconductor

A full quantum-mechanical treatment of the Bogoliubov-de Gennes equation for a single vortex in a d-wave superconductor is presented. First, we find low-energy states extended in four diagonal directions, which have no counterpart in a vortex of s-wave superconductors. The four-fold symmetry is due to 'quantum effect', which is enhanced when $p_{F}\xi$ is small. Second, for $p_{F}\xi \sim 1$, a peak with a large energy gap $E_{0}\sim \Delta$ is found in the density of states, which is due to the formation of the lowest bound states.Comment: 7pages, Revte

Half quantum vortex in superfluid 3^3He-A phase in parallel plate geometry

The half quantum vortex(HQV) in condensate has been studied, since it was predicted by Salomaa and Volovik in superfluid $^3$He-A phase. However, an experimental evidence for its existence has not been reported so far. Motivated by a recent experimental report by Yamashita et al\cite{yamashita}, we study the HQVs in superfluid $^3$He confined between two parallel plates with a gap D $\sim$ 10 $\mu$m in the presence of a magnetic field H $\sim$ 26 mT perpendicular to the parallel plates. We find that the bound HQVs are more stable than the singular vortices and free pairs of HQVs, when the rotation perpendicular to the parallel plates is below the critical speed, $\Omega_c \sim$ 2 rad/s. The bound pair of HQVs accompanies the tilting of ${\hat d}$-vector out of the plane, which leads to an additional absorption in NMR spectra. Our study appears to describe the temperature and rotation dependence of the observed satellite NMR signal, which supports the existence of the HQVs in $^3$He.Comment: 5 pages, 5 figure

Temperature-stable Gunn-diode oscillator

Oscillator consisting of Gunn diode embedded in coaxial circuit has excellent temperature stability and low fabrication costs as compared with automatic-frequency-control crystal oscillators

Bridging k- and q- Space in the Cuprates: Comparing ARPES and STM Results

A critical comparison is made between the ARPES-derived spectral function and STM studies of Friedel-like oscillations in Bi_2Sr_2CaCu_2O_{8+delta} (Bi2212). The data can be made approximately consistent, provided that (a) the elastic scattering seen in ARPES is predominantly small-angle scattering and (b) the `peak' feature seen in ARPES is really a dispersive `bright spot', smeared into a line by limited energy resolution; these are the `bright spots' which control the quasiparticle interferences. However, there is no indication of bilayer splitting in the STM data.Comment: 6 eps figures, revte

Possible f-wave superconductivity in Sr2_2RuO4_4?

Until recently it has been believed that the superconductivity in Sr$_2$RuO$_4$ is described by p-wave pairing. However, both the recent specific heat and the magnetic penetration depth measurements on the purest single crystals of Sr$_2$RuO$_4$ appear to be explained more consistently in terms of f-wave superconductivity. In order to further this hypothesis, we study theoretically the thermodynamics and thermal conductivity of f-wave superconductors in a planar magnetic field. We find the simple expressions for these quantities when $H \ll H_{c2}$ and $T \ll T_{c}$, which should be readily accessible experimentally.Comment: 6 pages, 2 figure

The relationship of the physical fitness of high school boys participating in a five and two period weekly programs in physical education

Thesis (Ed.M.)--Boston University, 1949. This item was digitized by the Internet Archive

Supercurrent in Nodal Superconductors

In recent years, a number of nodal superconductors have been identified; d-wave superconductors in high T_c cuprates, CeCoIn$_5$, and \kappa-(ET)_2Cu(NCS)_2, 2D f-wave superconductor in Sr_2RuO_4 and hybrid s+g-wave superconductor in YNi_2B_2C. In this work we conduct a theoretical study of nodal superconductors in the presence of supercurrent. For simplicity, we limit ourselves to d-wave and 2D f-wave superconductors. We compute the quasiparticle density of states and the temperature dependence of the depairing critical current in nodal superconductors, both of which are accessible experimentally.Comment: revtex4, 6 pages, 7 figures; fixed typos, updated references, trimmed introductio

Phytoplankton Community and Algal Toxicity at a Recurring Bloom in Sullivan Bay, Kabetogama Lake, Minnesota, USA

Kabetogama Lake in Voyageurs National Park, Minnesota, USA suffers from recurring late summer algal blooms that often contain toxin-producing cyanobacteria. Previous research identified the toxin microcystin in blooms, but we wanted to better understand how the algal and cyanobacterial community changed throughout an open water season and how changes in community structure were related to toxin production. Therefore, we sampled one recurring bloom location throughout the entire open water season. The uniqueness of this study is the absence of urban and agricultural nutrient sources, the remote location, and the collection of samples before any visible blooms were present. Through quantitative polymerase chain reaction (qPCR), we discovered that toxin-forming cyanobacteria were present before visible blooms and toxins not previously detected in this region (anatoxin-a and saxitoxin) were present, indicating that sampling for additional toxins and sampling earlier in the season may be necessary to assess ecosystems and human health risk