Bound states and the classical double copy

We extend the perturbative classical double copy to the analysis of bound systems. We first obtain the leading order perturbative gluon radiation field sourced by a system of interacting color charges in arbitrary time dependent orbits, and test its validity by taking relativistic bremsstrahlung and non-relativistic bound state limits. By generalizing the color to kinematic replacement rules recently used in the context of classical bremsstrahlung, we map the gluon emission amplitude to the radiation fields of dilaton gravity sourced by interacting particles in generic (self-consistent) orbits. As an application, we reproduce the leading post-Newtonian radiation fields and energy flux for point masses in non-relativistic orbits from the double copy of gauge theory.Comment: 9 pages, 1 figure, minor revisions to section II

Toward a Less Adversarial Relationship Between \u3cem\u3eChevron\u3c/em\u3e and \u3cem\u3eGardner\u3c/em\u3e

Veterans benefits are a creature of statute. As such, nearly every veterans benefits issue presented to the courts for resolution involves the interpretation of a statute, regulation, or sub-regulatory authority. Although veterans law has been subject to judicial review for over twenty-five years, the courts still have yet to develop a coherent doctrine regarding when to resolve ambiguity in favor of the veteran versus when to defer to the interpretations of the Department of Veterans Affairs. This Article explores three possible approaches to developing a coherent vision of how veteran friendliness and agency deference can coexist and provide more predictability in how to interpret veterans benefits laws

Are All Static Black Hole Solutions Spherically Symmetric?

The static black hole solutions to the Einstein-Maxwell equations are all spherically symmetric, as are many of the recently discovered black hole solutions in theories of gravity coupled to other forms of matter. However, counterexamples demonstrating that static black holes need not be spherically symmetric exist in theories, such as the standard electroweak model, with electrically charged massive vector fields. In such theories, a magnetically charged Reissner-Nordstrom solution with sufficiently small horizon radius is unstable against the development of a nonzero vector field outside the horizon. General arguments show that, for generic values of the magnetic charge, this field cannot be spherically symmetric. Explicit construction of the solution shows that it in fact has no rotational symmetry at all.Comment: 6 pages, plain TeX. Submitted to GRF Essay Competitio

Longitudinal multivariate tensor- and searchlight-based morphometry using permutation testing

Tensor based morphometry [1] was used to detect statistically significant regions of neuroanatomical change over time in a comparison between 36 probable Alzheimer's Disease patients and 20 age- and sexmatched controls. Baseline and twelve-month repeat Magnetic Resonance images underwent tied spatial normalisation [10] and longitudinal high-dimensional warps were then estimated. Analyses involved univariate and multivariate data derived from the longitudinal deformation fields. The most prominent findings were expansion of the fluid spaces, and contraction of the hippocampus and temporal region. Multivariate measures were notably more powerful, and have the potential to identify patterns of morphometric difference that would be overlooked by conventional mass-univariate analysis

Spectral energy distributions of quasars selected in the mid-infrared

We present preliminary results on fitting of SEDs to 142 z>1 quasars selected in the mid-infrared. Our quasar selection finds objects ranging in extinction from highly obscured, type-2 quasars, through more lightly reddened type-1 quasars and normal type-1s. We find a weak tendency for the objects with the highest far-infrared emission to be obscured quasars, but no bulk systematic offset between the far-infrared properties of dusty and normal quasars as might be expected in the most naive evolutionary schemes. The hosts of the type-2 quasars have stellar masses comparable to those of radio galaxies at similar redshifts. Many of the type-1s, and possibly one of the type-2s require a very hot dust component in addition to the normal torus emission.Comment: 4 pages, 2 figures, to appear in the proceedings of The Spectral Energy Distribution of Galaxies, Preston, September 2011, eds R.J. Tuffs & C.C. Popesc

Trapping of Pd, Au, and Cu by implantation-induced nanocavities and dislocations in Si

The gettering of metallic impurities by nanocavities formed in Si is a topic of both scientific importance and technological significance. Metallic precipitates observed in the regions where nanocavities were formed have been considered the result of the metal filling the nanocavities, either as elemental metal or a silicide phase. However, our transmission electron microscopy observations demonstrate that many of these precipitates are concentrated along dislocations, rather than randomly distributed as expected for precipitates formed by the filling of nanocavities. Consequently, the gettering contribution of dislocations in the lattice caused by nanocavity formation must be considered. For Pd, dislocations are the preferred sites for the precipitation of the metal silicide. We compare results of gettering by nanocavities and dislocations for Pd, Au, and Cu to determine which structure is the dominant influence for the formation of precipitates of these metals and/or their silicides

Formation and structural characterization of Ni nanoparticles embedded in SiO₂

Face-centered cubic Ni nanoparticles were formed in SiO₂ by ion implantation and thermal annealing. Small-angle x-ray scattering in conjunction with transmission electron microscopy was used to determine the nanoparticle size as a function of annealing temperature, whereas the local atomic structure was measured with x-ray absorption spectroscopy. The influence of finite-size effects on the nanoparticle structural properties was readily apparent and included a decrease in coordination number and bond length and an increase in structural disorder for decreasing nanoparticle size. Such results are consistent with the non-negligible surface-to-volume ratio characteristic of nanoparticles. In addition, temperature-dependent x-ray absorption spectroscopy measurements showed the mean vibrational frequency (as obtained from the Einstein temperature) decreased with decreasing nanoparticle size. This reduction was attributed to the greater influence of the loosely bound, under-coordinated surface atoms prevailing over the effects of capillary pressure, the former enhancing the low frequency modes of the vibrational density of statesThis work was financially supported by the Australian Synchrotron and the Australian Research Council with access to equipment provided by the Australian Nanofabrication Facility