The MAJORANA 76Ge neutrino less double-beta decay project: A brief update

At present, MAJORANA is a research and development (R&D) project to investigate the feasibility and cost of constructing and operating a one ton decay experiment with ~1000 kg of Ge detectors fabricated from germanium enriched to 86% in . The study will include three separate cryostats with various types of detectors: un-segmented, un-segmented point-contact, minimally segmented, and highly segmented. One cryostat will contain at least 30 kg of enriched (preferably point-contact) detectors. The performance of the cryostats and detectors as well as background levels will be investigated. The goal of the demonstrator project is to reach a discovery sensitivity of ~ 1026 y.Comment: 3 pages, no figure

Polarization of interacting bosons with spin

We demonstrate rigorously that in the absence of explicit spin-dependent forces one of the ground states of interacting bosons with spin is always fully polarized -- however complicated the many-body interaction potential might be. Depending on the particle spin, the polarized ground state will generally be degenerate with other states, but one can specify the exact degeneracy. For T>0 the magnetization and susceptibility necessarily exceed that of a pure paramagnet. These results are relevant to recent experiments exploring the relation between triplet superconductivity and ferromagnetism, and the Bose-Einstein condensation of atoms with spin. They eliminate the possibility, raised in some theoretical speculations, that the ground state or positive temperature state might be antiferromagnetic.Comment: v4: as published in PR

On the density-potential mapping in time-dependent density functional theory

The key questions of uniqueness and existence in time-dependent density functional theory are usually formulated only for potentials and densities that are analytic in time. Simple examples, standard in quantum mechanics, lead however to non-analyticities. We reformulate these questions in terms of a non-linear Schr\"odinger equation with a potential that depends non-locally on the wavefunction.Comment: 8 pages, 2 figure

New Wrinkles on an Old Model: Correlation Between Liquid Drop Parameters and Curvature Term

The relationship between the volume and surface energy coefficients in the liquid drop A^{-1/3} expansion of nuclear masses is discussed. The volume and surface coefficients in the liquid drop expansion share the same physical origin and their physical connection is used to extend the expansion with a curvature term. A possible generalization of the Wigner term is also suggested. This connection between coefficients is used to fit the experimental nuclear masses. The excellent fit obtained with a smaller number of parameters validates the assumed physical connection.Comment: 6 pages, 2 figure

Correlation equalities and upper bounds for the transverse Ising model

Starting from an exact formal identity for the two-state transverse Ising model and using correlation inequalities rigorous upper bounds for the critical temperature and the critical transverse field are obtained which improve effective results.Comment: 8 pages, 1 figur

In-Shoe Pressure Distribution During Ergometer Rowing In Novice And Experienced Rowers

Distribution of foot pressure during rowing has been minimally investigated. Foot pressure distribution is most likely altered with experience ca using an increase in stability and thus efficiency duirng the rowing stroke. This study evaluated in-shoe pressure distribution differences between novice and experienced collegiate rowers during rowing on the Concept II ergometer. In shoe pressure was measured in ten subjects, five novice and five experienced, while rowing at a stroke rate of 32-34 strokes per minute. The subjects wore the same model shoe with a Tekscan in-shoe pressure measurement system placed inside each shoe, only the dominant foot was studied. Data were sampled at a rate of 100 Hz. The following variables at the shoe-foot interface were investigated during the drive and the recovery of the stroke: peak forefoot pressure, peak rearfoot pressure, and displacement of the mediolateral and longitudinal center of pressure (COP). Peak pressures were investigated to discover how the pressure is distributed during the stroke. Comparison of the COP was used to indicate the stabililty of the foot during the drive phase. The experienced rowers had a high proportion of the total in-shoe pressure in the forefoot during the drive. Generally there was less pressure exerted on the recovery phase in the experienced subjects. These subjects also had a less variable mediolateral COP and an increase in the longitudinal COP plot. To apply force correctly during the drive it seems to be necessary to place a high proportion of the pressure in the forefoot. The trend toward decreased pressure on the recovery in the experienced rowers may reflect an increased efficiency due to experience. The decrease in the mediolateral COP deviation would appear to be related to increased stability. The longitudinal COP plot showed that with experience the plantar surface in contact with the shoe during the drive increases

Competing spin transfer and dissipation at Co/Cu(001) interfaces on femtosecond timescales

By combining interface-sensitive non-linear magneto-optical experiments with femtosecond time resolution and ab-initio time-dependent density functional theory, we show that optically excited spin dynamics at Co/Cu(001) interfaces proceeds via spin-dependent charge transfer and backtransfer between Co and Cu. This ultrafast spin transfer competes with dissipation of spin angular momentum mediated by spin-orbit coupling already on sub 100 fs timescales. We thereby identify the fundamental microscopic processes during laser-induced spin transfer at a model interface for technologically relevant ferromagnetic heterostructures.Comment: 5 pages, 4 figure

Experiment K-6-01. Distribution and biochemistry of mineral and matrix in the femurs of rats

Previous analyses of the composition of mineral and matrix in the bone of young rats following space flight has revealed deficits in calcium, phosphorus, and osteocalcin, a non-collagenous protein, without an associated decrease in collagen. To characterize the location and nature of this mineralization defect in a weight bearing long bone, the femur, researchers attempted to relate the spatial distribution of mineral in situ in the proximal, central and distal thirds of the femoral diaphysis to the biochemical composition of bone from the same area. Biochemical analyses revealed lower concentrations of calcium, phosphorus and osteocalcin but not collagen only in the central third of the diaphysis of the flight animals (F) compared to synchronous controls (S). Collagen concentration was reduced only in the proximal third of the diaphysis, where all 3 crosslinks, expressed as nM/mol collagen were higher in F than S. A new technique, x ray microtomography, with a resolution of 26 microns, was used to obtain semi-quantitative data on mineral distribution in reconstructed sections of wet whole bone. To improve the resolution of the mineral density distribution, images of the surfaces of cut sections were analyzed by backscattered electrons in a scanning electron microscope (BSE). There was good agreement between the results of the two stereochemical techniques which revealed distinct patterns of mineralization in transverse and longitudinal directions of the diaphysis. The novel methodology developed for this flight experiment shows considerable promise in elucidating the biochemical nature of what appear to be regional alterations in the mineralization of long bones of animals exposed to spaceflight