Generation and detection of NOON states in superconducting circuits

NOON states, states between two modes of light of the form $|N,0\rangle+e^{i\phi}|0,N\rangle$ allow for super-resolution interformetry. We show how NOON states can be efficiently produced in circuit quntum electrodynamics using superconducting phase qubits and resonators. We propose a protocol where only one interaction between the two modes is required, creating all the necessary entanglement at the start of the procedure. This protocol makes active use of the first three states of the phase qubits. Additionally, we show how to efficiently verify the success of such an experiment, even for large NOON states, using randomly sampled measurements and semidefinite programming techniques.Comment: 15 pages and 3 figure

Reliability and Validity of Ratings of Perceived Exertion in Persons With Multiple Sclerosis

Objective: To test the reliability and validity of using the Borg rating of perceived exertion (RPE) scale (ratings 6e20) in persons with multiple sclerosis (PwMS). Design: Nonrandomized repeated measures. Setting: Research laboratory. Participants: Volunteer sample (N=27) comprised of 16 PwMS (10 women) and 11 age-matched persons without multiple sclerosis (MS) (6 women). Clinical measures included symptomatic fatigue, depression, and MS functional capacity. Interventions: A submaximal cycling test was performed to estimate maximal capacity. Participants then pedaled for 2 minutes at 50% and 60% of predicted maximal oxygen consumption per unit time (V̇O2), and physiological measures and RPE were obtained (week 1: response protocol). One week later, participants replicated the prescribed V̇O2 using the RPE range from week 1 (week 2: reproduction protocol). V̇O2, heart rate, and respiratory quotient were measured continuously; RPE and workload were measured every minute; and blood lactate and mean arterial pressure were measured after exercise. Main Outcome Measures: RPE, workload, V̇O2, and heart rate from week 1 to week 2. Results: PwMS had greater fatigue (P2, and heart rate were similar between groups. Both groups had an intraclass correlation coefficient \u3e.86 for RPE, workload, and V̇O2. The intraclass correlation coefficient was comparatively lower for heart rate for both groups (MS group: .72, non-MS group: .83). RPE was highly correlated with V̇O2(rZ.691, P Conclusions: Results suggest that RPE can be reliably reproduced, is valid, and may be used in exercise prescription in mildly to moderately impaired PwMS during cycling exercise

Telemonitoring after discharge from hospital with heart failure: cost-effectiveness modelling of alternative service designs.

Objectives To estimate the cost-effectiveness of remote monitoring strategies versus usual care for adults recently discharged after a heart failure (HF) exacerbation. Design Decision analysis modelling of cost-effectiveness using secondary data sources. Setting Acute hospitals in the UK. Patients Patients recently discharged (within 28 days) after a HF exacerbation. Interventions Structured telephone support (STS) via human to machine (STS HM) interface, (2) STS via human to human (STS HH) contact and (3) home telemonitoring (TM), compared with (4) usual care. Main outcome measures The incremental cost per quality-adjusted life year (QALY) gained by each strategy compared to the next most effective alternative and the probability of each strategy being cost-effective at varying willingness to pay per QALY gained. Results TM was the most cost-effective strategy in the scenario using these base case costs. Compared with usual care, TM had an estimated incremental cost effectiveness ratio (ICER) of £11 873/QALY, whereas STS HH had an ICER of £228 035/QALY against TM. STS HM was dominated by usual care. Threshold analysis suggested that the monthly cost of TM has to be higher than £390 to have an ICER greater than £20 000/QALY against STS HH. Scenario analyses performed using higher costs of usual care, higher costs of STS HH and lower costs of TM do not substantially change the conclusions. Conclusions Cost-effectiveness analyses suggest that TM was an optimal strategy in most scenarios, but there is considerable uncertainty in relation to clear descriptions of the interventions and robust estimation of costs

Quantum Effects in the Mechanical Properties of Suspended Nanomechanical Systems

We explore the quantum aspects of an elastic bar supported at both ends and subject to compression. If strain rather than stress is held fixed, the system remains stable beyond the buckling instability, supporting two potential minima. The classical equilibrium transverse displacement is analogous to a Ginsburg-Landau order parameter, with strain playing the role of temperature. We calculate the quantum fluctuations about the classical value as a function of strain. Excitation energies and quantum fluctuation amplitudes are compared for silicon beams and carbon nanotubes.Comment: RevTeX4. 5 pages, 3 eps figures. Submitted to Physical Review Letter

Pulmonary arterial hypertension: a new era in management

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Pulmonary arterial hypertension (PAH) is a heterogeneous condition with a wide range of causes. The diagnosis is often delayed or missed. PAH is covert in its early stages, when its detection and treatment should have the most impact. Access in Australia to effective PAH therapies has lagged behind that in other affluent countries. New agents for PAH, now becoming available, improve symptoms and reduce pulmonary resistance, with some demonstrating an ability to reverse remodelling of the right ventricle. Best management of PAH is comprehensive and multidisciplinary. Centres of excellence are needed in geographically strategic areas. Aggressive efforts must be made to diagnose PAH and to facilitate access to effective therapies.Anne M Keogh, Keith D McNeil, Trevor Williams, Eli Gabbay and Leslie G Clelan

Dynamics of a suspended nanowire driven by an ac Josephson current in an inhomogeneous magnetic field

We consider a voltage-biased nanoelectromechanical Josephson junction, where a suspended nanowire forms a superconducting weak-link, in an inhomogeneous magnetic field. We show that a nonlinear coupling between the Josephson current and the magnetic field generates a Laplace force that induces a whirling motion of the nanowire. By performing an analytical and a numerical analysis, we demonstrate that at resonance, the amplitude-phase dynamics of the whirling movement present different regimes depending on the degree of inhomogeneity of the magnetic field: time independent, periodic and chaotic. Transitions between these regimes are also discussed.Comment: 7 pages, 5 figure

Nonlinear response of a driven vibrating nanobeam in the quantum regime

We analytically investigate the nonlinear response of a damped doubly clamped nanomechanical beam under static longitudinal compression which is excited to transverse vibrations. Starting from a continuous elasticity model for the beam, we consider the dynamics of the beam close to the Euler buckling instability. There, the fundamental transverse mode dominates and a quantum mechanical time-dependent effective single particle Hamiltonian for its amplitude can be derived. In addition, we include the influence of a dissipative Ohmic or super-Ohmic environment. In the rotating frame, a Markovian master equation is derived which includes also the effect of the time-dependent driving in a non-trivial way. The quasienergies of the pure system show multiple avoided level crossings corresponding to multiphonon transitions in the resonator. Around the resonances, the master equation is solved analytically using Van Vleck perturbation theory. Their lineshapes are calculated resulting in simple expressions. We find the general solution for the multiple multiphonon resonances and, most interestingly, a bath-induced transition from a resonant to an antiresonant behavior of the nonlinear response.Comment: 25 pages, 5 figures, submitted to NJ

Synchronization by Nonlinear Frequency Pulling

We analyze a model for the synchronization of nonlinear oscillators due to reactive coupling and nonlinear frequency pulling motivated by the physics of arrays of nanoscale oscillators. We study the model for the mean field case of all-to-all coupling, deriving results for the onset of synchronization as the coupling or nonlinearity increase, and the fully locked state when all the oscillators evolve with the same frequency