Efficient orthogonal control of tunnel couplings in a quantum dot array

Electrostatically-defined semiconductor quantum dot arrays offer a promising platform for quantum computation and quantum simulation. However, crosstalk of gate voltages to dot potentials and inter-dot tunnel couplings complicates the tuning of the device parameters. To date, crosstalk to the dot potentials is routinely and efficiently compensated using so-called virtual gates, which are specific linear combinations of physical gate voltages. However, due to exponential dependence of tunnel couplings on gate voltages, crosstalk to the tunnel barriers is currently compensated through a slow iterative process. In this work, we show that the crosstalk on tunnel barriers can be efficiently characterized and compensated for, using the fact that the same exponential dependence applies to all gates. We demonstrate efficient calibration of crosstalk in a quadruple quantum dot array and define a set of virtual barrier gates, with which we show orthogonal control of all inter-dot tunnel couplings. Our method marks a key step forward in the scalability of the tuning process of large-scale quantum dot arrays.Comment: 8 pages, 7 figure

Applying Complexity Theory to Solve Hospitality Contrarian Case Conundrums: Illuminating Happy-Low and Unhappy-High Performing Frontline Service Employees

Purpose: This paper aims to advance a configural asymmetric theory of the complex antecedents to hospitality employee happiness-at-work and managers’ assessments of employees’ quality of work performance. The study transcends variable and case-level analyses to go beyond prior statistical findings of small-to-medium effect sizes of happiness–performance relationships; the study here identifies antecedent paths involving high-versus-low happy employees associating with high-versus-low managers’ assessments of these employees’ performances. Design/methodology/approach: The study merges data from surveys of employees (n = 247) and surveys completed by their managers (n = 43) and by using qualitative comparative analysis via the software program, fsQCA.com. The study analyzes data from Janfusan Fancyworld, the largest (in revenues and number of employees) tourism business group in Taiwan; Janfusan Fancyworld includes tourist hotels, amusement parks, restaurants and additional firms in related service sectors. Findings: The findings support the four tenets of configural analysis and theory construction: recognize equifinality of different solutions for the same outcome, test for asymmetric solutions, test for causal asymmetric outcomes for very high versus very low happiness and work performance and embrace complexity.Research limitations/implications: Additional research in other firms and additional countries is necessary to confirm the usefulness of examining algorithms for predicting very high (low) happiness and very high (low) quality of work performance. The implications are substantial that configural theory and research will resolve perplexing happiness–performance conundrums. Practical implications: The study provides useful case-level algorithms involving employees’ demographic characteristics and their assessments of work facet-specifics which are useful for explaining very high happiness-at-work and high quality of work performance (as assessed by managers) – as well as algorithms explaining very low happiness and very low quality of work performance. Originality/value: The study is the first to propose and test the tenets of configural theory in the context of hospitality frontline service employees’ happiness-at-work and managers’ assessments of these employees’ quality of work performances

Unraveling the Infrared Transient VVV-WIT-06: The Case for the Origin as a Classical Nova

Indexación: Scopus.E.Y.H. acknowledges the support provided by the National Science Foundation under Grant No. AST-1613472 and by the Florida Space Grant Consortium. L.G. acknowledges support from the FINCA visitor programme. The research work at the Physical Research Laboratory is funded by the Department of Space, Government of India. Facility: Magellan: Baade(FIRE).The enigmatic near-infrared transient VVV-WIT-06 underwent a large-amplitude eruption of unclear origin in 2013 July. Based on its light curve properties and late-time post-outburst spectra, various possibilities have been proposed in the literature for the origin of the object, namely a Type I supernova, a classical nova (CN), or a violent stellar merger event. We show that, of these possibilities, an origin in a CN outburst convincingly explains the observed properties of VVV-WIT-06. We estimate that the absolute K-band magnitude of the nova at maximum was M k = -8.2 ±0.5, its distance d = 13.35 ±2.18 kpc, and the extinction A v = 15.0 ±0.55 mag. © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-4357/aae5d

Chromogranin A in uremia: Progressive retention of immunoreactive fragments

Chromogranin A in uremia: Progressive retention of immunoreactive fragments. Chromogranin A is a soluble protein that is stored and released with catecholamines from their secretory vesicles. Its measurement is a probe of exocytotic sympathoadrenal activity, and in plasma it may also be a useful tool in the diagnosis of peptide producing endocrine neoplasms. Because we have found that chromogranin A is elevated in secondary (uremic) hyperparathyroidism, we systematically investigated the influence of renal dysfunction and its attendant hyperparathyroidism on chromogranin A in several subject groups: normal controls (serum creatinine≤1.2 mg/dl), nonazotemic renal transplant recipients, nonazotemic subjects with glomerular disease (serum creatinine between 1.2 and 2 mg/dl), mid-range renal disease subjects (serum creatinine between 2 and 7.5 mg/dl), and end-stage renal disease subjects (serum creatinine <7.5 mg/dl). Plasma chromogranin A rose with deterioration of renal function, and the rise was independent of etiologic diagnosis, blood pressure, or indices of sympathoadrenal activity or hyperparathyroidism. Size fractionation of uremic plasma by gel filtration, and immunoextraction by region-specific anti-chromo-granin A (anti-N-terminal, anti-C-terminal, and antimid-molecule) antibodies suggested that chromogranin A immunoreactivity circulates in uremia as lower molecular weight fragments of the parent chromogranin A molecule, with mid-molecule fragments the major constituent. This immunoreactivity is only minimally removed by peritoneal dialysis and is not at all hemodialyzable. The uremia-dose-dependent accumulation of chromogranin A immunoreactive fragments in renal failure suggests that the kidney is a major site of disposition or removal of the immunoreactivity. Furthermore, lack of detectable chromogranin A immunoreactivity in normal subjects' urine suggests that the immunoreactivity is destroyed as it is removed by the kidney. We conclude that plasma chromogranin A increases in proportion to degree of renal insufficiency and that renal function must therefore be controlled when using plasma chromogranin A in the investigation of amine or peptide hormone storage and release

Analysis of some localized boundary-domain integral equations for transmission problems with variable coefficients

This is the post-print version of the Article. The official published version can be found at the links below - Copyright @ 2011 Birkhäuser Boston.Some segregated systems of direct localized boundary-domain integral equations (LBDIEs) associated with several transmission problems for scalar PDEs with variable coefficients are formulated and analyzed for a bounded domain composed of two subdomains with a coefficient jump over the interface. The main results established in the paper are the LBDIE equivalence to the original transmission problems and the invertibility of the corresponding localized boundary-domain integral operators in corresponding Sobolev spaces function spaces.This research was supported by the EPSRC grant EP/H020497/1: ”Mathematical analysis of Localized Boundary-Domain Integral Equations for Variable-Coefficient Boundary Value Problems” and partly by the Georgian Technical University grant in the case of the third author

Polymers grafted to porous membranes

We study a single flexible chain molecule grafted to a membrane which has pores of size slightly larger than the monomer size. On both sides of the membrane there is the same solvent. When this solvent is good, i.e. when the polymer is described by a self avoiding walk, it can fairly easily penetrate the membrane, so that the average number of membrane crossings tends, for chain length $N\to\infty$, to a positive constant. The average numbers of monomers on either side of the membrane diverges in this limit, although their ratio becomes infinite. For a poor solvent, in contrast, the entire polymer is located, for large $N$, on one side of the membrane. For good and for theta solvents (ideal polymers) we find scaling laws, whose exponents can in the latter case be easily understood from the behaviour of random walks.Comment: 4 pages, 6 figure

Szeg\"o kernel asymptotics and Morse inequalities on CR manifolds

We consider an abstract compact orientable Cauchy-Riemann manifold endowed with a Cauchy-Riemann complex line bundle. We assume that the manifold satisfies condition Y(q) everywhere. In this paper we obtain a scaling upper-bound for the Szeg\"o kernel on (0, q)-forms with values in the high tensor powers of the line bundle. This gives after integration weak Morse inequalities, analogues of the holomorphic Morse inequalities of Demailly. By a refined spectral analysis we obtain also strong Morse inequalities which we apply to the embedding of some convex-concave manifolds.Comment: 40 pages, the constants in Theorems 1.1-1.8 have been modified by a multiplicative constant 1/2 ; v.2 is a final updat