Energy Measurements and Preparation of Canonical Phase States of a Nano-Mechanical Resonator

We show that a continuous quantum non-demolition measurement of the energy of a nanomechanical resonator can be achieved by monitoring the resonator with a quantum point contact via a Cooper-pair box. This technique can further be used to prepare highly non-classical states of two resonators, such as canonical phase-reference states, and so-called "noon" states.Comment: 4 pages, revtex 4, 3 eps figures. v2: improvements to presentatio

The Impact of Interstate Highways on Land Use Conversion

Between 1945 and 2007, the United States lost 19.3 % of its agricultural land. Over the same time period, the construction of the 42,500 mile interstate highway system lowered transportation costs and opened large tracts of land for development. This paper assesses the impact of the interstate highway system on agricultural land loss in Georgia and uses the empirical estimates to simulate agricultural land loss resulting from the construction of additional interstate highways. Using a historical data set of agricultural land and interstate highway mileage, empirical estimates indicate that each additional mile of interstate highway reduces agricultural land by 468 acres. The impact of interstate highways is heterogeneous across initial level of county development. Urban counties convert 70 % more land than the full sample estimates. Simulation results show that additions to the interstate system create further loss of agricultural land. The results imply that future conservation programs need to consider how to mitigate the impact of the interstate highway system

Atom Probe Tomography Characterization of Thin Copper Layers on Aluminum Deposited by Galvanic Displacement

″Ultrathin″ metallization layers on the order of nanometers in thickness are increasingly used in semiconductor interconnects and other nanostructures. Aqueous deposition methods are attractive methods to produce such layers due to their low cost, but formation of ultrathin layers has proven challenging, particularly on oxide-coated substrates. This work focused on the formation of thin copper layers on aluminum, by galvanic displacement from alkaline aqueous solutions. Analysis by atom probe tomography (APT) showed that continuous copper films of approximately 1 nm thickness were formed, apparently the first demonstration of deposition of ultrathin metal layers on oxidized substrates from aqueous solutions. The APT reconstructions indicate that deposited copper replaced a portion of the surface oxide film on aluminum. The results are consistent with mechanisms in which surface hydride species on aluminum mediate deposition, either by directly reducing cupric ions or by inducing electronic conduction in the oxide, thus enabling cupric ion reduction by Al metal

Drive ‘Til You Qualify: Credit Quality and Household Location

A deeper understanding of the credit-sorting process is essential when considering the extent to which home foreclosures are driven by price contagion or an underlying spatial pattern of mortgage quality. Adapting household location theory, we find that credit constrained households follow “drive-\u27til-you-qualify” behavior leading to rising credit quality with distance from the CBD while unconstrained households exhibit declining credit quality. Individual level mortgage loan-to-income data for the 100 largest MSAs show credit constrained behavior either throughout the urban area or concentrated in the suburbs. Meta analysis of the credit sorting estimates identify MSA characteristics associated with each pattern