Measuring fine molecular structures with luminescence signal from an alternating current scanning tunneling microscope

In scanning tunneling microscopy induced luminescence (STML), the photon counting is measured to reflect the single-molecule properties, e.g., the first molecular excited state. The energy of the first excited state is typically determined by a rising position of the photon counting as a function of the bias voltage between the tip and the substrate. It remains a challenge to determine the precise rise position of the current due to the possible experimental noise. In this work, we propose an alternating current version of STML to resolve the fine structures in the photon counting measurement. The measured photon counting and the current at the long-time limit show a sinusoidal oscillation. The zero-frequency component of the current shows knee points at the precise voltage as the fraction of the detuning between the molecular gap and the DC component of bias voltage. We propose to measure the energy level with discontinuity of the first derivative of such zero-frequency component. The current method will extend the application of STML in terms of measuring molecular properties

Entropic uncertainty relations for Markovian and non-Markovian processes under a structured bosonic reservoir

The uncertainty relation is a fundamental limit in quantum mechanics and is of great importance to quantum information processing as it relates to quantum precision measurement. Due to interactions with the surrounding environment, a quantum system will unavoidably suffer from decoherence. Here, we investigate the dynamic behaviors of the entropic uncertainty relation of an atom-cavity interacting system under a bosonic reservoir during the crossover between Markovian and non-Markovian regimes. Specifically, we explore the dynamic behavior of the entropic uncertainty relation for a pair of incompatible observables under the reservoir-induced atomic decay effect both with and without quantum memory. We find that the uncertainty dramatically depends on both the atom-cavity and the cavity-reservoir interactions, as well as the correlation time, $\tau$, of the structured reservoir. Furthermore, we verify that the uncertainty is anti-correlated with the purity of the state of the observed qubit-system. We also propose a remarkably simple and efficient way to reduce the uncertainty by utilizing quantum weak measurement reversal. Therefore our work offers a new insight into the uncertainty dynamics for multi-component measurements within an open system, and is thus important for quantum precision measurements.Comment: 17 pages, 9 figures, to appear in Scientific Report

Higher-order QCD corrections to Υ\Upsilon decay into double charmonia

In this work, we study the exclusive decay of $\Upsilon$ into $J/\psi$ in association with $\eta_c$ ($\chi_{c0,1,2}$). The decay widths for different helicity configurations are evaluated up to QCD next-to-leading order within the nonrelativistic QCD framework. We find that the QCD corrections notably mitigate the renormalization scale dependence of the decay widths for all the processes. The branching fraction of $\Upsilon\rightarrow J/\psi+\chi_{c1}$ is obtained as $3.73^{+5.10+0.10}_{-2.06-1.19}\times 10^{-6}$, which agrees well with the Belle measurement, i.e., ${\rm Br}(\Upsilon\rightarrow J/\psi+\chi_{c1})=(3.90\pm1.21\pm0.23)\times10^{-6}$. For the other processes, our results of the branching fractions are compatible with the upper limits given by the Belle experiments, except for $\Upsilon(2S)\to J/\psi +\chi_{c1}$, where some tension exists between theory and experiment. Having the polarized decay widths, we study the $J/\psi$ polarization, which turn out to be independent of any nonperturbative parameters. Further, according to our calculation, it is promising to measure all the processes at Super B factory thanks to the high luminosity.Comment: 13 pages, 2 figures, 3 tables, to match the version accepted for publication in PR

catena-Poly[[diaqua­calcium(II)]-bis­(μ-quinoline-3-carboxyl­ato)]

In the title complex, [Ca(C10H6NO2)2(H2O)2]n, the CaII ion is eight-coordinated by six carboxyl­ate O atoms from four separate quinoline-3-carboxyl­ate ligands, two of which are bidentate chelate and two bridging, and two water mol­ecules in a distorted square-anti­prismatic geometry. The bridging groups form a polymeric chain substructure extending along the c axis, the chains being connected by coordinated-water O—H⋯N and O—H⋯Ocarboxyl­ate hydrogen bonds into a three-dimensional framework structure

Cross-cultural validation of the educational needs assessment tool into Chinese for use in severe knee osteoarthritis

© 2018 Zhao et al. Background: Patient education is an integral part of the management of osteoarthritis. The educational needs assessment tool (ENAT) was developed in the UK to help direct needs-based patient education in rheumatic diseases. Aim: The aim of the study was to adapt and validate the ENAT into Chinese, for use in severe knee osteoarthritis (KOA). Methods: This cross-cultural validation study took two phases: 1) adaptation of the ENAT into Chinese (CENAT) and 2) validation of the CENAT. The Construct validity was determined using factor analysis and criterion-related validity by comparing data from CENAT with data from different self-efficacy scales: patient–physician interactions scale (PEPPI-10), self-efficacy for rehabilitation outcome scale (SER), and the self-efficacy for exercise scale (SEE). Results: The sample comprised 196 patients, with mean age 63.6±8.7 years, disease duration was 11.5 years, and 57.1% were female. The CENAT was found to have high internal consistency. The CENAT had weak correlations with the Chinese versions of PEPPI r=0.40, SER r=0.40, and SEE r=0.39. There were no correlations with age r=−0.03 or disease duration r=−0.11. Conclusion: The ENAT translated well into Chinese and has evidence of validity in KOA. Future studies will further inform its usefulness in clinics, community, and online settings