Quantification and Characterization of Leakage Errors

We present a general framework for the quantification and characterization of leakage errors that result when a quantum system is encoded in the subspace of a larger system. To do this we introduce new metrics for quantifying the coherent and incoherent properties of the resulting errors, and we illustrate this framework with several examples relevant to superconducting qubits. In particular, we propose two quantities: the leakage and seepage rates, which together with average gate fidelity allow for characterizing the average performance of quantum gates in the presence of leakage and show how the randomized benchmarking protocol can be modified to enable the robust estimation of all three quantities for a Clifford gate set.Comment: 14 pages, 6 figures, and appendice

Can Money Change Who We Are? Estimating the Effects of Unearned Income on Measures of Incentive-Enhancing Personality Traits

The importance of noncognitive childhood skills in predicting higher wages is well documented in economics. This paper studies the reverse. Using surveys of lottery winners, we analyze the effects of unearned income on the Big Five personality traits. After correcting for potential endogeneity problems from prize sizes, we find that unearned income improves traits that predict pro-social and cooperative behaviors, preferences for social contact, empathy, and gregariousness, and reduces individuals' tendency toward negative emotional states: known in economics literature as incentive-enhancing personality traits. Our results support the possibility of scope for later interventions to improve the personality traits of adults.noncognitive skills, personality traits, lottery winners, instrumental variables, unearned income

Lipid Coated Gold Nanoparticle Cores: Synthesis and Characterization

Including environmental, industrial, and biomedical sciences, applications of gold nanoparticles are on the forefront of research in many areas. By altering the surface treatment of spherical gold nanoparticle cores, particularly those smaller than 100 nm (nanometers), one can influence their potential use in a number of ways. Lipid coated nanoparticles with specifically selected surface ligands can be used for multiple biomedical functions, including medical imaging, for use as colorimetric and plasmonic sensors within the body, and as cell or organelle specific targets for therapeutic drug delivery or cancer treatment. Here, spherical gold nanoparticles ranging in size from 8-40 nm (avg. diameter 23-48 nm) have been synthesized and coated with poly(allylamine hydrochloride) (PAH) and a mixed lipid solution of 1:1 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (POPS) and lysophosphatidylcholine (LPC), two of the four major types of lipids found in the human body. Characterization was performed using a NanoSight LM10HS particle sizer, and shows a gradual increase in size after each step in the coating process for nanoparticle cores ranging in size from 16-27 nm. The thickness of these purified and lipid coated nanoparticles was consistently 2-3 times that of the PAH coated sample it was layered onto, suggesting a successful, multi-layered coat that ranges in size based on the PAH coated core size. UV-Vis spectroscopy shows a slight red shift, indicating an increase in size and change in refractive index, which supports the presence of lipid coating on the PAH coated gold nanoparticle cores

Improved Log(gf) Values for Lines of Ti I and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937 (Accurate Transition Probabilities for Ti I)

New atomic transition probability measurements for 948 lines of Ti I are reported. Branching fractions from Fourier transform spectra and from spectra recorded using a 3 m echelle spectrometer are combined with published radiative lifetimes from laser-induced fluorescence measurements to determine these transition probabilities. Generally good agreement is found in comparisons to the NIST Atomic Spectra Database. The new Ti I data are applied to re-determine the Ti abundance in the photospheres of the Sun and metal-poor star HD 84937 using many lines covering a range of wavelength and excitation potential to explore possible non-local thermal equilibrium effects. The variation of relative Ti/Fe abundance with metallicity in metal-poor stars observed in earlier studies is supported in this study.NSF AST-1211055, AST-0908978, AST-1211585NSF REU grant AST-1004881ESO Science Archive Facility 073.D-0024, 266.D-5655NASA NAS 5-26555Astronom

Characterizing quantum dynamics with initial system-environment correlations

We fully characterize the reduced dynamics of an open quantum system initially correlated with its environment. Using a photonic qubit coupled to a simulated environment we tomographically reconstruct a superchannel---a generalised channel that treats preparation procedures as inputs---from measurement of the system alone, despite its coupling to the environment. We introduce novel quantitative measures for determining the strength of initial correlations, and to allow an experiment to be optimised in regards to its environment.Comment: 10 pages, 15 figure

Cavity cooling of an ensemble spin system

We describe how sideband cooling techniques may be applied to large spin ensembles in magnetic resonance. Using the Tavis-Cummings model in the presence of a Rabi drive, we solve a Markovian master equation describing the joint spin-cavity dynamics to derive cooling rates as a function of ensemble size. Our calculations indicate that the coupled angular momentum subspaces of a spin ensemble containing roughly $10^{11}$ electron spins may be polarized in a time many orders of magnitude shorter than the typical thermal relaxation time. The described techniques should permit efficient removal of entropy for spin-based quantum information processors and fast polarization of spin samples. The proposed application of a standard technique in quantum optics to magnetic resonance also serves to reinforce the connection between the two fields, which has recently begun to be explored in further detail due to the development of hybrid designs for manufacturing noise-resilient quantum devices.Comment: 14 pages + 5 figure

Can money change who we are? estimating the effects of unearned income on measures of incentive-enhancing personality

The importance of noncognitive childhood skills in predicting higher wages is well documented in economics. This paper studies the reverse. Using surveys of lottery winners, we analyze the effects of unearned income on the Big Five personality traits. After correcting for potential endogeneity problems from prize sizes, we find that unearned income improves traits that predict pro-social and cooperative behaviors, preferences for social contact, empathy, and gregariousness, and reduces individuals' tendency toward negative emotional states: known in economics literature as incentive-enhancing personality traits. Our results support the possibility of scope for later interventions to improve the personality traits of adults