Hunds Rule Theory for Heavy Fermion Superconductors

In this paper, a generalization of standard spin fluctuation theory is considered which takes into account orbital degeneracy effects which are critical for describing f electrons. This theory leads to an instability for a superconducting pair state which obeys Hunds rules. Such a state has L=5, S=1, and J=4. The degeneracy of this state is broken by crystalline effects, and realistic calculations for $UPt_3$ find a resultant pair state with $\Gamma_6^-$ symmetry, consistent with current experimental constraints.Comment: revised manuscript, 15 pages (Plain TeX with macros), plus 1 postscript figur

Copper Tellurium Oxides - A Playground for Magnetism

A variety of copper tellurium oxide minerals are known, and many of them exhibit either unusual forms of magnetism, or potentially novel spin liquid behavior. Here, I review a number of the more interesting materials with a focus on their crystalline symmetry and, if known, the nature of their magnetism. Many of these exist (so far) in mineral form only, and most have yet to have their magnetic properties studied. This means a largely unexplored space of materials awaits our exploration.Comment: Contribution to a dedicated issue of the Journal of Magnetism and Magnetic Materials in memory of Art Freema

A strong coupling critique of spin fluctuation driven charge order in underdoped cuprates

Charge order has emerged as a generic feature of doped cuprates, leading to important questions about its origin and its relation to superconductivity. Recent experiments on two classes of hole doped cuprates indicate a novel d-wave symmetry for the order. These were motivated by earlier spin fluctuation theoretical studies based on an expansion about hot spots in the Brillouin zone that indicated such order would be competitive with d-wave superconductivity. Here, we reexamine this problem by solving strong coupling equations in the full Brillouin zone. Our results find that bond-oriented order, as seen experimentally, is strongly suppressed, indicating that the charge order must have a different origin.Comment: 5 pages, 4 figures plus Supplemental material

Bidirectional Reflectance Modeling of Non-homogeneous Plant Canopies

The objective of this research is to develop a 3-dimensional radiative transfer model for predicting the bidirectional reflectance distribution function (BRDF) for heterogeneous vegetation canopies. The model (named BIGAR) considers the angular distribution of leaves, leaf area index, the location and size of individual subcanopies such as widely spaced rows or trees, spectral and directional properties of leaves, multiple scattering, solar position and sky condition, and characteristics of the soil. The model relates canopy biophysical attributes to down-looking radiation measurements for nadir and off-nadir viewing angles. Therefore, inversion of this model, which is difficult but practical should provide surface biophysical pattern; a fundamental goal of remote sensing. Such a model also will help to evaluate atmospheric limitations to satellite remote sensing by providing a good surface boundary condition for many different kinds of canopies. Furthermore, this model can relate estimates of nadir reflectance, which is approximated by most satellites, to hemispherical reflectance, which is necessary in the energy budget of vegetated surfaces

Infrared Absorption Associated with Strong Hydrogen Bonds

Several investigators have proposed that there exists a more or less unique relation between the O-O distance in O-H-O hydrogen bonds and the shift of O-H vibrational frequency. [1-5] However, the meager intensities of some bands which have been ascribed to this vibration (notably in nickel dimethyl-glyoxime and potassium dihydrogen phosphate) have made us a little skeptical of the correlation inthe case of very short, and possibly symmetrical, hydrogen bonds

Analysis of Policy Issues Relating to Public Investment in Private Freight Infrastructure, MTI Report 99-03

The Norman Y. Mineta International Institute for Surface Transportation Policy Studies (IISTPS) at San José State University conducted this study to review the issues and implications involved in the investment of public funds in private freight infrastructure. After thorough legal research, the project team reached the following conclusions: LEGAL ANALYSIS: The California legislature has the legal power to invest public funds in privately-owned freight infrastructure projects State Highway funds, excepting gas tax revenues, may be used for investment in freight infrastructure projects. Gas tax revenues are restricted to highway use by current interpretations of the California Constitution. A challenge to this interpretation is not recommended. Gas tax revenues may be invested in roadway segments of freight infrastructure projects. RECOMMENDATIONS An analytical system of guidelines should be developed to score and evaluate any proposed freight infrastructure project. Economic development must be included in these scoring guidelines. Public agencies should maintain political contacts in order to control the political short-circuits of the planning process. The California Department of Transportation should develop a Freight Improvement Priority System for the purpose of prioritizing all freight improvement projects

Secular Effects of Tidal Damping in Compact Planetary Systems

We describe the long-term evolution of compact systems of terrestrial planets, using a set of simulations that match the statistical properties of the observed exoplanet distribution. The evolution is driven by tidal dissipation in the planetary interiors, but the systems evolve as a whole due to secular gravitational interactions. We find that, for Earth-like dissipation levels, planetary orbits can be circularised out to periods of order 100 days, an order of magnitude larger than is possible for single planets. The resulting distribution of eccentricities is a qualitative match to that inferred from transit timing variations, with a minority of non-zero eccentricities maintained by particular secular configurations. The coupling of the tidal and secular processes enhance the inward migration of the innermost planets in these systems, and can drive them to short orbital periods. Resonant interactions of both the mean motion and secular variety are observed, although the interactions are not strong enough to drive systemic instability in most cases. However, we demonstrate that these systems can easily be driven unstable if coupled to giant planets on longer period orbits.Comment: 17 pages, 22 figures, 2 tables, submitted to Monthly Notices of the Royal Astronomical Societ