Quantum spill out in few-nanometer metal gaps: Effect on gap plasmons and reflectance from ultrasharp groove arrays

Plasmons in ultranarrow metal gaps are highly sensitive to the electron density profile at the metal surfaces. Using a fully quantum mechanical approach, we study the effects of electron spill-out on gap plasmons and reflectance from ultrasharp metal grooves. We demonstrate that the mode index of ultranarrow gap plasmons converges to the bulk refractive index in the limit of vanishing gap and, thereby, rectify the unphysical divergence found in classical models. Surprisingly, spill-out also significantly increases the plasmonic absorption for few-nanometer gaps and lowers the reflectance from arrays of ultrasharp metal grooves. These findings are explained in terms of enhanced gap plasmon absorption taking place inside the gap 1-2 {\AA} from the walls and delocalization near the groove bottom. Reflectance calculations taking spill-out into account are shown to be in much better agreement with measurements compared with classical models

Quantum spill-out in nanometer-thin gold slabs: Effect on plasmon mode index and plasmonic absorption

A quantum mechanical approach and local response theory are applied to study plasmons propagating in nanometer-thin gold slabs sandwiched between different dielectrics. The metal slab supports two different kinds of modes, classified as long-range and short-range plasmons. Quantum spill-out is found to significantly increase the imaginary part of their mode indices, and, surprisingly, even for slabs wide enough to approach bulk the increase is 20%. This is explained in terms of enhanced plasmonic absorption, which mainly takes place at narrow peaks located near the slab surface

Chinese Enterprise Reform as a Market Process

The reform of China's enterprise system increasingly reflects the outcome of China's emerging property rights market. We distinguish between a centrally-directed reform strategy, with characteristics similar to those of a Pigouvian tax, and a market-driven reform process, which captures the essential features of a Coasian approach to social cost. The Coase Theorem postulates that eliminating transaction costs and attaching well specified property rights to public goods that generate externalities will allow uncoordinated economic agents to negotiate institutional arrangements that produce socially efficient allocation of resources. Extending Coase's reasoning to the case of socialist transition ' we argue that reforms that expand competition, move toward well-specified assignment of ownership rights to public enterprises, and reduce transaction costs will motivate the "ultimate" owners, including officials of national and sub-national government agencies, to reconfigure their assets or to combine their assets with those of other jurisdictions and/or private investors to create more efficient ownership arrangements. We review the extent to which China's reforms have established the conditions for an effective market in ownership rights to industrial property. We tabulate progress from 1 980 to present along the three major analytic dimensions inherent in Coase's analysis: competition, property rights, and transaction costs. We conclude that the sheer size and diversity of China's industrial economy will motivate a continuation of decentralized reform initiatives. To support this Coasian reform process, central and provincial governments need to expand initiatives to clarify property rights, particularly the right of alienation, reduce impediments to competition, and facilitate the reduction of transaction costs.http://deepblue.lib.umich.edu/bitstream/2027.42/39466/3/wp76.pd

Confined hidden vector dark matter

We argue that the lightest vector bound states of a confining hidden sector communicating with the Standard Model through the Higgs portal are stable and are viable candidates of dark matter. The model is based on an SU(2) gauge group with a scalar field in its fundamental representation and the stability of the lightest vector bound state results from the existence of a custodial symmetry. As the relic density depends essentially on the scale of confinement in the hidden sector, Lambda_HS, agreement with WMAP abundance requires Lambda_HS in the 20-120 TeV range.Comment: 6 page

Riemannian curvature measures

A famous theorem of Weyl states that if $M$ is a compact submanifold of euclidean space, then the volumes of small tubes about $M$ are given by a polynomial in the radius $r$, with coefficients that are expressible as integrals of certain scalar invariants of the curvature tensor of $M$ with respect to the induced metric. It is natural to interpret this phenomenon in terms of curvature measures and smooth valuations, in the sense of Alesker, canonically associated to the Riemannian structure of $M$. This perspective yields a fundamental new structure in Riemannian geometry, in the form of a certain abstract module over the polynomial algebra $\mathbb R[t]$ that reflects the behavior of Alesker multiplication. This module encodes a key piece of the array of kinematic formulas of any Riemannian manifold on which a group of isometries acts transitively on the sphere bundle. We illustrate this principle in precise terms in the case where $M$ is a complex space form.Comment: Corrected version, to appear in GAF

Diffusion coefficients for multi-step persistent random walks on lattices

We calculate the diffusion coefficients of persistent random walks on lattices, where the direction of a walker at a given step depends on the memory of a certain number of previous steps. In particular, we describe a simple method which enables us to obtain explicit expressions for the diffusion coefficients of walks with two-step memory on different classes of one-, two- and higher-dimensional lattices.Comment: 27 pages, 2 figure

The Allocation of Advertising and Research Dollars in the Florida Orange Juice Industry

This study considers the allocation of Florida citrus‐grower money between advertising and research programs to maximize grower revenue net of program costs. The allocation depends on the impact of advertising on demand and the impacts of research on the cost of production and supply. A number of studies have estimated the impact of advertising on OJ demand, but little is known about the impact of research. Research on citrus greening, a disease that has no known cure, is examined in the present study. There are no past studies to reliably gauge the impact of this research. The approach taken here is to ask if a given amount of research dollars is needed to reduce average production costs by certain amount, then what should be spent on advertising based on past estimates of the elasticity of demand with respect to advertising. The optimal ratio of advertising to research dollars increases with the advertising elasticity and declines with the amount of research money needed to reduce average costs. The results of this study provide a range for this ratio based on different advertising elasticities and amounts of research dollars needed to reduce production costs. The approach provides an indication of the importance of advertising given expectations on the research needed to successfully fight this diseaseorange juice, returns to research, advertising, Agribusiness, Food Security and Poverty,

THE IMPACT OF THE REDUCTION IN THE AUSTRALIAN ORANGE-JUICE TARIFF

After substantial reduction in the Australian orange juice tariff, citrus growers in that country shifted their efforts away from Valencia orange production towards Navel oranges intended for the fresh market. Australia has been successful in penetrating the world market for fresh oranges. Given the large size of the orange industry in Florida, however, it is unlikely that Florida growers could follow the same model if the U.S. orange juice were substantially reduced or eliminated.oranges, tariffs, Australia, International Relations/Trade,

A triangular thin shell finite element: Linear analysis

The formulation of the linear stiffness matrix for a doubly-curved triangular thin shell element, using a modified potential energy principle, is described. The strain energy component of the potential energy is expressed in terms of displacements and displacement gradients by use of consistent Koiter strain-displacement equations. The element inplane and normal displacement fields are approximated by complete cubic polynomials. The interelement displacement admissibility conditions are met in the global representation by imposition of constraint conditions on the interelement boundaries; the constraints represent the modification of the potential energy. Errors due to the nonzero strains under rigid body motion are shown to be of small importance for practical grid refinements through performance of extensive comparison analyses