Atomic layer deposition of titanium nitride for quantum circuits

Superconducting thin films with high intrinsic kinetic inductance are of great importance for photon detectors, achieving strong coupling in hybrid systems, and protected qubits. We report on the performance of titanium nitride resonators, patterned on thin films (9-110 nm) grown by atomic layer deposition, with sheet inductances of up to 234 pH/square. For films thicker than 14 nm, quality factors measured in the quantum regime range from 0.4 to 1.0 million and are likely limited by dielectric two-level systems. Additionally, we show characteristic impedances up to 28 kOhm, with no significant degradation of the internal quality factor as the impedance increases. These high impedances correspond to an increased single photon coupling strength of 24 times compared to a 50 Ohm resonator, transformative for hybrid quantum systems and quantum sensing.Comment: 10 pages, 8 figures including supplemental material

CO and C_2 Absorption Toward W40 IRS 1a

The H II region W40 harbors a small group of young, hot stars behind roughly 9 magnitudes of visual extinction. We have detected gaseous carbon monoxide (CO) and diatomic carbon (C_2) in absorption toward the star W40 IRS 1a. The 2-0 R0, R1, and R2 lines of 12CO at 2.3 micron were measured using the CSHELL on the NASA IR Telescope Facility (with upper limits placed on R3, R4, and R5) yielding an N_CO of (1.1 +/- 0.2) x 10^18 cm^-2. Excitation analysis indicates T_kin > 7 K. The Phillips system of C_2 transitions near 8775 Ang. was measured using the Kitt Peak 4-m telescope and echelle spectrometer. Radiative pumping models indicate a total C_2 column density of (7.0 +/- 0.4) x 10^14 cm^-2, two excitation temperatures (39 and 126 K), and a total gas density of n ~ 250 cm^-3. The CO ice band at 4.7 micron was not detected, placing an upper limit on the CO depletion of delta < 1 %. We postulate that the sightline has multiple translucent components and is associated with the W40 molecular cloud. Our data for W40 IRS 1a, coupled with other sightlines, shows that the ratio of CO/C_2 increases from diffuse through translucent environs. Finally, we show that the hydrogen to dust ratio seems to remain constant from diffuse to dense environments, while the CO to dust ratio apparently does not.Comment: To appear in The Astrophysical Journal 17 pages total, 5 figures Also available at http://casa.colorado.edu/~shuping/research/w40/w40.htm

Single-qubit optical quantum fingerprinting

We analyze and demonstrate the feasibility and superiority of linear optical single-qubit fingerprinting over its classical counterpart. For one-qubit fingerprinting of two-bit messages, we prepare `tetrahedral' qubit states experimentally and show that they meet the requirements for quantum fingerprinting to exceed the classical capability. We prove that shared entanglement permits 100% reliable quantum fingerprinting, which will outperform classical fingerprinting even with arbitrary amounts of shared randomness.Comment: 4 pages, one figur

Occultation Mapping of the Central Engine in the Active Galaxy MCG -6-30-15

The colossal power output of active galactic nuclei (AGN) is believed to be fueled by the accretion of matter onto a supermassive black hole. This central accreting region of AGN has hitherto been spatially unresolved and its structure therefore unknown. Here we propose that a previously reported `deep minimum' in the X-ray intensity of the AGN MCG-6-30-15, was due to a unique X-ray occultation event and that it probes structure of the central engine on scales < 1e14 cm, or 1.4e-7 arcseconds. The data are consistent with a bright central source surrounded by a less intense ring, which we identify with the inner edge of an accretion disk. These may be the first direct measurements of the spatial structure and geometry of the accreting black-hole system in an active galaxy.If the ring of X-ray emission is identified with the inner edge of an accretion disk, upper limits on the BH mass can be derived. Our occultation interpretation is controversial in the sense that X-ray variability in AGNs is normally attributed to intrinsic physical changes in the X-ray emission region, such as disk or coronal instabilities.Comment: 15 pages, 2 Figures. Latex with separate postscript figure files. Accepted for publication in ApJ Letter

Transport, optical and electronic properties of the half metal CrO2

The electronic structure of CrO_2 is critically discussed in terms of the relation of existing experimental data and well converged LSDA and GGA calculations of the electronic structure and transport properties of this half metal magnet, with a particular emphasis on optical properties. We find only moderate manifestations of many body effects. Renormalization of the density of states is not large and is in the typical for transition metals range. We find substantial deviations from Drude behavior in the far-infrared optical conductivity. These appear because of the unusually low energy of interband optical transitions. The calculated mass renormalization is found to be rather sensitive to the exchange-correlation functional used and varies from 10% (LSDA) to 90% (GGA), using the latest specific heat data. We also find that dressing of the electrons by spin fluctuations, because of their high energy, renormalizes the interband optical transition at as high as 4 eV by about 20%. Although we find no clear indications of strong correlations of the Hubbard type, strong electron-magnon scattering related to the half metallic band structure is present and this leads to a nontrivial temperature dependence of the resistivity and some renormalization of the electron spectra.Comment: 9 Revtex 2 column pages, including 8 postscript figures. Two more figures are included in the submission that are not embedded in the paper, representing DOS and bandstructure of the paramagnetic CrO

Quantum Corrections to the Reissner-Nordstrom and Kerr-Newman Metrics: Spin 1

A previous evaluation of one-photon loop corrections to the energy-momentum tensor has been extended to particles with unit spin and speculations are presented concerning general properties of such forms.Comment: 21 pages, 1 Figur

Growth and texture of Spark Plasma Sintered Al2O3 ceramics: a combined analysis of X-rays and Electron Back Scatter Diffraction

Textured alumina ceramics were obtained by Spark Plasma Sintering (SPS) of undoped commercial a-Al2O3 powders. Various parameters (density, grain growth, grain size distribution) of the alumina ceramics, sintered at two typical temperatures 1400{\deg}C and 1700{\deg}C, are investigated. Quantitative textural and structural analysis, carried out using a combination of Electron Back Scattering Diffraction (EBSD) and X-ray diffraction (XRD), are represented in the form of mapping, and pole figures. The mechanical properties of these textured alumina ceramics include high elastic modulus and hardness value with high anisotropic nature, opening the door for a large range of applicationsComment: 16 pages, 6 figures, submitted to J. Appl. Phy

Bioinformatics advances in saliva diagnostics

There is a need recognized by the National Institute of Dental & Craniofacial Research and the National Cancer Institute to advance basic, translational and clinical saliva research. The goal of the Salivaomics Knowledge Base (SKB) is to create a data management system and web resource constructed to support human salivaomics research. To maximize the utility of the SKB for retrieval, integration and analysis of data, we have developed the Saliva Ontology and SDxMart. This article reviews the informatics advances in saliva diagnostics made possible by the Saliva Ontology and SDxMart

Confirmation of the Planetary Microlensing Signal and Star and Planet Mass Determinations for Event OGLE-2005-BLG-169

We present Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations of the source and lens stars for planetary microlensing event OGLE-2005-BLG-169, which confirm the relative proper motion prediction due to the planetary light curve signal observed for this event. This (and the companion Keck result) provide the first confirmation of a planetary microlensing signal, for which the deviation was only 2%. The follow-up observations determine the flux of the planetary host star in multiple passbands and remove light curve model ambiguity caused by sparse sampling of part of the light curve. This leads to a precise determination of the properties of the OGLE-2005-BLG-169Lb planetary system. Combining the constraints from the microlensing light curve with the photometry and astrometry of the HST/WFC3 data, we find star and planet masses of M_* = 0.69+- 0.02 M_solar and m_p = 14.1 +- 0.9 M_earth. The planetary microlens system is located toward the Galactic bulge at a distance of D_L = 4.1 +- 0.4 kpc, and the projected star-planet separation is a_perp = 3.5 +- 0.3 AU, corresponding to a semi-major axis of a = 4.0 (+2.2 -0.6) AU.Comment: 21 pages, including 5 figures, published in Ap

Universal continuous-variable quantum computation: Requirement of optical nonlinearity for photon counting

Although universal continuous-variable quantum computation cannot be achieved via linear optics (including squeezing), homodyne detection and feed-forward, inclusion of ideal photon counting measurements overcomes this obstacle. These measurements are sometimes described by arrays of beam splitters to distribute the photons across several modes. We show that such a scheme cannot be used to implement ideal photon counting and that such measurements necessarily involve nonlinear evolution. However, this requirement of nonlinearity can be moved "off-line," thereby permitting universal continuous-variable quantum computation with linear optics.Comment: 6 pages, no figures, replaced with published versio