Symmetries and collective excitations in large superconducting circuits

The intriguing appeal of circuits lies in their modularity and ease of fabrication. Based on a toolbox of simple building blocks, circuits present a powerful framework for achieving new functionality by combining circuit elements into larger networks. It is an open question to what degree modularity also holds for quantum circuits -- circuits made of superconducting material, in which electric voltages and currents are governed by the laws of quantum physics. If realizable, quantum coherence in larger circuit networks has great potential for advances in quantum information processing including topological protection from decoherence. Here, we present theory suitable for quantitative modeling of such large circuits and discuss its application to the fluxonium device. Our approach makes use of approximate symmetries exhibited by the circuit, and enables us to obtain new predictions for the energy spectrum of the fluxonium device which can be tested with current experimental technology

Quasars in the MAMBO blank field survey

Our MAMBO 1.2 mm blank field imaging survey of ~0.75 sqd has uncovered four unusually bright sources, with flux densities between 10 and 90 mJy, all located in the Abell 2125 field. The three brightest are flat spectrum radio sources with bright optical and X-ray counterparts. Their mm and radio flux densities are variable on timescales of months. Their X-ray luminosities classify them as quasars. The faintest of the four mm bright sources appears to be a bright, radio-quiet starburst at z~3, similar to the sources seen at lower flux densities in the MAMBO and SCUBA surveys. It may also host a mildly obscured AGN of quasar-like X-ray luminosity. The three non-thermal mm sources imply an areal density of flat spectrum radio sources higher by at least 7 compared with that expected from an extrapolation of the lower frequency radio number counts.Comment: 8 pages, 7 figures. Accepted for publication by A&

SU(3) Clebsch-Gordan Coefficients for Baryon-Meson Coupling at Arbitrary N_c

We present explicit formulae for the SU(3) Clebsch-Gordan coefficients that are relevant for the couplings of large N_c baryons to mesons. In particular, we compute the Clebsch-Gordan series for the coupling of the octet (associated with mesons, and remains the correct representation at large N_c) to the large N_c analogs of the baryon octet and decuplet representations.Comment: 8 pages, no figures, ReVTe

Asymptotic solvers for ordinary differential equations with multiple frequencies

We construct asymptotic expansions for ordinary differential equations with highly oscillatory forcing terms, focusing on the case of multiple, non-commensurate frequencies. We derive an asymptotic expansion in inverse powers of the oscillatory parameter and use its truncation as an exceedingly effective means to discretize the differential equation in question. Numerical examples illustrate the effectiveness of the method

Size-tuneable nanometric MRI contrast agents for the imaging of molecular weight dependent transport processes

Purpose: To evaluate size-tuneable nanomeric glycol-chitosan-DTPA-Gd conjugates as MRI contrast agents for the imaging of molecular weight (MW) dependent transport processes. Material & Methods: Glycol chitosans (GC) – DTPA conjugates of precisely controlled MWs were synthesised and evaluated in mice against Gd-DTPA using times series of high-resolution MRI images of trunk, head, and xenograft flank tumours. All animal studies were approved by the local ethics committee and the UK authorities. Results: GC-DTPA modification ratio was one DTPA per 3.9 – 5.13 of GC monomers. GC-DTAPGd provided overall superior contrast compared to Gd-DTPA with the duration of the enhancement depending on MW (≥ 1h for 40kD). Kidneys showed early enhancement also in the renal pelvis suggesting renal elimination. Imaging of the head with GC-DTPA-Gd allowed detailed anatomical identification of specific blood vessels in particular with the high MW agent. Sequential high-resolution isotropic imaging of established A431 xenograft flank tumours with DTPA-Gd and GC-DTPA-Gd demonstrated that the initial delivery of the contrast agents was well correlated with blood supply. Subsequent tissue transport was primarily by diffusion and was limited by molecular weight. The data also highlight the role of heterogeneity in CA distribution that was again more prominent for the high MW agent. Conclusion: GC-DTPA-Gd with identical physical chemical properties but precisely controlled MW allow isotropic high-resolution three-dimensional imaging of molecular weight dependent transport processes which could potentially lead to clinical biomarkers for molecular weight dependent drug transport and support selection of suitable tumour models for pre-clinical development

Systematic computation of crystal field multiplets for X-ray core spectroscopies

We present a new approach to computing multiplets for core spectroscopies, whereby the crystal field is constructed explicitly from the positions and charges of surrounding atoms. The simplicity of the input allows the consideration of crystal fields of any symmetry, and in particular facilitates the study of spectroscopic effects arising from low symmetry environments. The interplay between polarization directions and crystal field can also be conveniently investigated. The determination of the multiplets proceeds from a Dirac density functional atomic calculation, followed by the exact diagonalization of the Coulomb, spin-orbit and crystal field interactions for the electrons in the open shells. The eigenstates are then used to simulate X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering spectra. In examples ranging from high symmetry down to low symmetry environment, comparisons with experiments are done with unadjusted model parameters as well as with semi-empirically optimized ones. Furthermore, predictions for the RIXS of low-temperature MnO and for Dy in a molecular complex are proposed.Comment: Accepted for publication in Phys. Rev.

The MPCP Longitudinal Educational Growth Study Third Year Report

This is the third-year report in a five-year evaluation of the Milwaukee Parental Choice Program (MPCP). The MPCP, which began in 1990, provides government-funded vouchers for low-income children to attend private schools in the City of Milwaukee. The maximum voucher amount in 2008-09 was $6,607, and approximately 20,000 children used a voucher to attend either secular or religious private schools. The MPCP is the oldest and largest urban school voucher program in the United States. This evaluation was authorized by Wisconsin Act 125 enacted in 2005

Software Holography: Interferometric Data Analysis for the Challenges of Next Generation Observatories

Next generation radio observatories such as the MWA, LWA, LOFAR, CARMA and SKA provide a number of challenges for interferometric data analysis. These challenges include heterogeneous arrays, direction-dependent instrumental gain, and refractive and scintillating atmospheric conditions. From the analysis perspective, this means that calibration solutions can not be described using a single complex gain per antenna. In this paper we use the optimal map-making formalism developed for CMB analyses to extend traditional interferometric radio analysis techniques--removing the assumption of a single complex gain per antenna and allowing more complete descriptions of the instrumental and atmospheric conditions. Due to the similarity with holographic mapping of radio antenna surfaces, we call this extended analysis approach software holography. The resulting analysis algorithms are computationally efficient, unbiased, and optimally sensitive. We show how software holography can be used to solve some of the challenges of next generation observations, and how more familiar analysis techniques can be derived as limiting cases.Comment: in revie