34 research outputs found
State Support for Clean Energy Deployment. Lessons Learned for Potential Future Policy
Proposed federal clean energy initiatives and climate legislation have suggested significant increases to federal funding for clean energy deployment and investment. Many states and utilities have over a decade of experience and spend billions of public dollars every year to support EE/RE deployment through programs that reduce the cost of technologies, provide financing for EE/RE projects, offer technical assistance, and educate market participants. Meanwhile, constraints on public expenditures at all levels of government continue to call upon such programs to demonstrate their value. This report reviews the results of these programs and the specific financial incentives and financing tools used to encourage clean energy investment. Lessons from such programs could be used to inform the future application of EE/RE incentives and financing tools. These lessons learned apply to use of distributed resources and the historical focus of these EE/RE programs
Dirac quasiparticles in the mixed state
Energies and wave functions are calculated for d-wave quasiparticles in the
mixed state using the formalism of Franz and Tesanovic for the low-lying energy
levels. The accuracy of the plane-wave expansion is explored by comparing
approximate to exact results for a simplified one-dimensional problem, and the
convergence of the plane- wave expansion to the two-dimensional case is
studied. The results are used to calculate the low-energy tunneling density of
states and the low-temperature specific heat, and these theoretical results are
compared to semiclassical treatments and to the available data. Implications
for the muon spin resonance measurements of vortex core size are also
discussed.Comment: 13 pages, 15 figures, RevTeX. References corrected. A factor of 2 in
the results has been corrected, and the conclusions have been update
Supercurrent in Nodal Superconductors
In recent years, a number of nodal superconductors have been identified;
d-wave superconductors in high T_c cuprates, CeCoIn, 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
BonFIRE: A multi-cloud test facility for internet of services experimentation
BonFIRE offers a Future Internet, multi-site, cloud testbed, targeted at the Internet of Services community, that supports large scale testing of applications, services and systems over multiple, geographically distributed, heterogeneous cloud testbeds. The aim of BonFIRE is to provide an infrastructure that gives experimenters the ability to control and monitor the execution of their experiments to a degree that is not found in traditional cloud facilities. The BonFIRE architecture has been designed to support key functionalities such as: resource management; monitoring of virtual and physical infrastructure metrics; elasticity; single document experiment descriptions; and scheduling. As for January 2012 BonFIRE release 2 is operational, supporting seven pilot experiments. Future releases will enhance the offering, including the interconnecting with networking facilities to provide access to routers, switches and bandwidth-on-demand systems. BonFIRE will be open for general use late 2012
On the ubiquity of trivial torsion on elliptic curves
The purpose of this paper is to give a "down--to--earth" proof of the
well--known fact that a randomly chosen elliptic curve over the rationals is
most likely to have trivial torsion
Quasiparticle thermal Hall angle and magnetoconductance in YBa_2Cu_3O_x
We present a way to extract the quasiparticle (qp) thermal conductivity
Kappa_e and mean-free-path in YBa_2Cu_3O_x, using the thermal Hall effect and
the magnetoconductance of Kappa_e. The results are very consistent with heat
capacity experiments. Moreover, we find a simple relation between the thermal
Hall angle Theta_Q and the H-dependence of Kappa_e, as well as numerical
equality between Theta_Q and the electrical Hall angle. The findings also
reveal an anomalously anisotropic scattering process in the normal state.Comment: 4 pages in Tex, 5 figures in EPS; replaced on 5/12/99, minor change
Magnetic Field Dependence of Electronic Specific Heat in Pr_{1.85} Ce_{0.15} CuO_4
The specific heat of electron-doped Pr_{1.85} Ce_{0.15} CuO_4 single crystals
is reported for the temperature range 2 - 10 K and magnetic field range 0 - 10
T. A non-linear magnetic field dependence is observed for the field range 0 - 2
T. Our data supports a model with lines of nodes in the gap function of these
superconductors. Theoretical calculations of the electronic specific heat for
dirty d-wave, clean d-wave, and s-wave symmetries are compared to our data.Comment: 10 pages Latex and 4 eps figures, submitted to Phys. Rev.
Theory of Scanning Tunneling Spectroscopy of Magnetic-Field-Induced Discrete Nodal States in a D-Wave Superconductor
In the presence of an external magnetic field, the low lying elementary
excitations of a d-wave superconductor have quantized energy and their momenta
are locked near the node direction. It is argued that these discrete states can
most likely be detected by a local probe, such as a scanning tunneling
microscope. The low temperature local tunneling conductance on the Wigner-Seitz
cell boundaries of the vortex lattice is predicted to show peaks spaced as . The peak is anomalous, and it is present only
if the superconducting order parameter changes sign at certain points on the
Fermi surface. Away from the cell boundary, where the superfluid velocity is
nonzero, each peak splits, in general, into four peaks, corresponding to the
number of nodes in the order parameter.Comment: RevTeX 3.0, 4 pages, 3 figures (included
Heat Conduction in -(BEDT-TTF)Cu(NCS)
The first study of thermal conductivity, , in a quasi-two-dimensional
organic superconductor of the -(BEDT-TTF)X family reveals features
analogous to those already observed in the cuprates. The onset of
superconductivity is associated with a sudden increase in which can be
suppressed by the application of a moderate magnetic field. At low
temperatures, a finite linear term - due to a residual electronic contribution-
was resolved. The magnitude of this term is close to what is predicted by the
theory of transport in unconventional superconductors.Comment: 5 pages, 4 figures include
Anisotropy of magnetothermal conductivity in Sr2RuO4
The dependence of in-plane and interplane thermal conductivities of Sr2RuO4
on temperature, as well as magnetic field strength and orientation, is
reported. We found no notable anisotropy in the thermal conductivity for the
magnetic field rotation parallel to the conducting plane in the whole range of
experimental temperatures and fields, except in the vicinity of the upper
critical field Hc2, where the anisotropy of the Hc2 itself plays a dominant
role. This finding imposes strong constraints on the possible models of
superconductivity in Sr2RuO4 and supports the existence of a superconducting
gap with a line of nodes running orthogonal to the Fermi surface cylinder.Comment: published in Phys. Rev. Lett. 4pages, 4 eps figures, LaTe