Imaging coherent transport in graphene (Part II): Probing weak localization

Graphene has opened new avenues of research in quantum transport, with potential applications for coherent electronics. Coherent transport depends sensitively on scattering from microscopic disorder present in graphene samples: electron waves traveling along different paths interfere, changing the total conductance. Weak localization is produced by the coherent backscattering of waves, while universal conductance fluctuations are created by summing over all paths. In this work, we obtain conductance images of weak localization with a liquid-He-cooled scanning probe microscope, by using the tip to create a movable scatterer in a graphene device. This technique allows us to investigate coherent transport with a probe of size comparable to the electron wavelength. Images of magnetoconductance \textit{vs.} tip position map the effects of disorder by moving a single scatterer, revealing how electron interference is modified by the tip perturbation. The weak localization dip in conductivity at B=0 is obtained by averaging magnetoconductance traces at different positions of the tip-created scatterer. The width $\Delta B_{WL}$ of the dip yields an estimate of the electron coherence length $L_\phi$ at fixed charge density. This "scanning scatterer" method provides a new way of investigating coherent transport in graphene by directly perturbing the disorder configuration that creates these interferometric effects.Comment: 18 pages, 7 figure

Determining Off-Site Damages to Non-Residential Property from Leaking Underground Storage Tanks Using Contingent Valuation Analysis

This research evaluates the effect of leaking underground storage tanks (LUSTs) from gas stations on nearby commercial property when the existing data is incomplete or imperfect. While methodologies such as hedonic regression may be preferred for evaluating the effects of LUSTs on property values, the rigorous data requirements of these methodologies often cannot be met. Contingent valuation analysis is one method that enables estimation of losses when the data available is incomplete. A contingent valuation analysis of real estate professionals in South Carolina and Ohio provides estimates of commercial property losses, which ranges from 0-40%, depending on environmental conditions and proximity to the source. This research has developed a methodology for estimating real estate property value losses when data requirements cannot be fulfilled based on the best available data.Environmental contamination; Commercial property; Underground storage tanks; Contingent valuation analysis

Bringing More Competition to Real Estate Brokerage

This paper provides an economic analysis of the residential real estate brokerage industry. We find that the traditional model for residential real estate brokerage services may be dated, and could be improved substantially with some public policy interventions that spur innovation. We believe that there are numerous barriers to entry that are slowing the emergence of new models for serving consumers. Some of these barriers are likely to be anti-competitive. Examples include discrimination against new brokerage models and online brokers who wish to join multiple listing services; state legislation that would require minimum service requirements, effectively preventing "a la carte" offerings; and prohibitions by real estate commissions on providing rebates to customers. In our opinion, none of these practices should be allowed. We offer three broad policy recommendations: First, federal and state antitrust authorities should carefully scrutinize efforts to limit competition in the residential real estate brokerage market. Second, state governments should refrain from adopting laws or rules that inhibit competition in real estate brokerage. Third, Congress should allow the Federal Reserve Board and the Treasury Department to permit banks, which have long been natural potential entrants into this business, to offer residential real estate brokerage services through separately capitalized affiliates. We do not know which business models are likely to succeed in the marketplace for residential real estate services in the future. We do believe, however, that judicious public policy interventions could have a marked impact on improving services and lowering costs for home buyers and sellers. Click Here for a shorter version of this paper, published in The Milken InstituteReview .

Futures Trading in Cheese: How Will it Work?

Livestock Production/Industries, Marketing,

Futures Contracts for Milk: How Will They Work?

Livestock Production/Industries, Marketing,

Federal Order Milk Pricing and the Economic Viability of the Upper Midwest Dairy Industry

Agricultural and Food Policy, Demand and Price Analysis, Livestock Production/Industries,

The Basic Formula Price Futures Contract: A New Dairy Industry Risk Management Tool

Livestock Production/Industries, Marketing, Risk and Uncertainty,

Options Trading in Cheese Futures Contracts: How Will it Work?

Marketing,