Nucleon-nucleon resonances at intermediate energies using a complex energy formalism

We apply our method of complex scaling, valid for a general class of potentials, in a search for nucleon-nucleon S-matrix poles up to 2 GeV laboratory kinetic energy. We find that the realistic potentials JISP16, constructed from inverse scattering, and chiral field theory potentials N$^3$LO and N$^2$LO$_{opt}$ support resonances in energy regions well above their fit regions. In some cases these resonances have widths that are narrow when compared with the real part of the S-matrix pole.Comment: 7 pages, 5 figures, 2 Table

Spin-injection Hall effect in a planar photovoltaic cell

Successful incorporation of the spin degree of freedom in semiconductor technology requires the development of a new paradigm allowing for a scalable, non-destructive electrical detection of the spin-polarization of injected charge carriers as they propagate along the semiconducting channel. In this paper we report the observation of a spin-injection Hall effect (SIHE) which exploits the quantum-relativistic nature of spin-charge transport and which meets all these key requirements on the spin detection. The two-dimensional electron-hole gas photo-voltaic cell we designed to observe the SIHE allows us to develop a quantitative microscopic theory of the phenomenon and to demonstrate its direct application in optoelectronics. We report an experimental realization of a non-magnetic spin-photovoltaic effect via the SIHE, rendering our device an electrical polarimeter which directly converts the degree of circular polarization of light to a voltage signal.Comment: 14 pages, 4 figure

Holographic Renormalization of general dilaton-axion gravity

We consider a very general dilaton-axion system coupled to Einstein-Hilbert gravity in arbitrary dimension and we carry out holographic renormalization for any dimension up to and including five dimensions. This is achieved by developing a new systematic algorithm for iteratively solving the radial Hamilton-Jacobi equation in a derivative expansion. The boundary term derived is valid not only for asymptotically AdS backgrounds, but also for more general asymptotics, including non-conformal branes and Improved Holographic QCD. In the second half of the paper, we apply the general result to Improved Holographic QCD with arbitrary dilaton potential. In particular, we derive the generalized Fefferman-Graham asymptotic expansions and provide a proof of the holographic Ward identities.Comment: 42 pages. v2: two references added. Version published in JHEP. v3: fixed minor typos in eqs. (1.6), (2.3), (3.20), (A.3), (B.8), (B.12) and (B.22

"A Path to Community Development, The Community Reinvestment Act, Lending Discrimination, and the Role of Community Development Banks"

The establishment of a system of federally regulated, for-profit, community development banks (CDBs) would help to fill the financial gap in areas inadequately served by traditional banks, requirements of the Community Reinvestment Act (CRA) notwithstanding. These organizations would be charged with delivering credit, payment, and savings opportunities and providing basic financing to households and small businesses in underserved areas. Such a system would not substitute for the CRA, but rather act as a supplement to current regulation. Proposed exemptions from CRA compliance for depository institutions that invest in the equity of a CDB would weaken the existing law by diluting the investment of the depository institution in its own particular community. Such proposals (under which "investment" has been defined to be as little as one-quarter of one percent of total assets) are not consistent with the spirit of the CRA and would negate the beneficial dialogue that takes place between the institution and the community in which it operates.

First-order transition in small-world networks

The small-world transition is a first-order transition at zero density $p$ of shortcuts, whereby the normalized shortest-path distance undergoes a discontinuity in the thermodynamic limit. On finite systems the apparent transition is shifted by $\Delta p \sim L^{-d}$. Equivalently a ``persistence size'' $L^* \sim p^{-1/d}$ can be defined in connection with finite-size effects. Assuming $L^* \sim p^{-\tau}$, simple rescaling arguments imply that $\tau=1/d$. We confirm this result by extensive numerical simulation in one to four dimensions, and argue that $\tau=1/d$ implies that this transition is first-order.Comment: 4 pages, 3 figures, To appear in Europhysics Letter

"An Alternative in Small Business Finance, Community-Based Factoring Companies and Small Business Lending"

According to Papadimitriou, Phillips, and Wray, at a time when small businesses are suffering from a credit crunch, "niche" financial institutions are filling the void left by more traditional sources of financing, such as commercial banks. The authors argue that the most important of these niche players are community-based factor companies, which are rapidly expanding from their client base in apparel and textiles to finance a range of firms in everything from electronics to health care. The purchase of accounts receivable by factors enhances the balance sheets of their clients, making it easier for the clients to obtain bank financing. Also, because factors are more interested in the creditworthiness of a client's customers than of the client itself, they are willing to extend loans in excess of collateral to rapidly growing businesses. Because factors are becoming an increasingly important source of financing for small and start-up businesses, the authors propose that factors be encouraged to play a broader role in financing firms in distressed communities by (1) making some factors eligible for funding and assistance under legislation regulating community development financial institutions and (2) by allowing investments by banks in factors to count toward compliance under the Community Reinvestment Act.