Scaling Relations in the Vortex State of Nodal Superconductors

In contrast to multigap superconductors (e.g. MgB$_{2}$), the low-temperature properties of nodal superconductors are dominated by nodal excitations. Here we extend for a variety of nodal superocnductors the earlier work by Simon and Lee and K\"ubert and Hirschfeld. The scaling relations seen in the thermodynamics and the thermal conductivity will provide an unequivocal test of nodal superconductivity.Comment: 9 pages, 3 figure

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

Tomography of a spin qubit in a double quantum dot

We investigate a range of methods to perform tomography in a solid-state qubit device, for which a priori initialization and measurement of the qubit is restricted to a single basis of the Bloch sphere. We explore and compare several methods to acquire precise descriptions of additional states and measurements, quantifying both stochastic and systematic errors, ultimately leading to a tomographically-complete set that can be subsequently used in process tomography. We focus in detail on the example of a spin qubit formed by the singlet-triplet subspace of two electron spins in a GaAs double quantum dot, although our approach is quite general.Comment: 10 pages, 5 figures, comments welcome; v2 published versio

ECONOMIC EFFECTS OF COPPER-NICKEL DEVELOPMENT IN NORTHEAST MINNESOTA

Computer simulations of industry gross output, employment and earnings changes associated with alternative copper-nickel development scenarios are presented in this report. The direct and indirect economic effects of seven development scenarios are projected for a mining impact Study Area in St. Louis County, Minnesota.Community/Rural/Urban Development, Resource /Energy Economics and Policy,

BCS theory of nodal superconductors

This course has a dual purpose. First we review the successes of the weak-coupling BCS theory in describing new classes of superconductors discovered since 1979. They include the heavy-fermion superconductors, high-Tc cuprate superconductors, organic superconductors, Sr2RuO4, etc. Second, we present the quasiclassical approximation introduced by Volovik, which we extend to describe the thermodynamics and the thermal conductivity of the vortex state in nodal superconductors. This approach provides the most powerful tool to identify the symmetry of the energy gap function Delta(k) in these new superconductors.Comment: 31 pages, 33 figure