Tunable coupling to a mechanical oscillator circuit using a coherent feedback network

We demonstrate a fully cryogenic microwave feedback network composed of modular superconducting devices connected by transmission lines and designed to control a mechanical oscillator coupled to one of the devices. The network features an electromechanical device and a tunable controller that coherently receives, processes and feeds back continuous microwave signals that modify the dynamics and readout of the mechanical state. While previous electromechanical systems represent some compromise between efficient control and efficient readout of the mechanical state, as set by the electromagnetic decay rate, the tunable controller produces a closed-loop network that can be dynamically and continuously tuned between both extremes much faster than the mechanical response time. We demonstrate that the microwave decay rate may be modulated by at least a factor of 10 at a rate greater than $10^4$ times the mechanical response rate. The system is easy to build and suggests that some useful functions may arise most naturally at the network-level of modular, quantum electromagnetic devices.Comment: 11 pages, 6 figures, final published versio

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Generation and Efficient Measurement of Single Photons Using Superconducting Circuits

In this thesis, I demonstrate and evaluate an on-demand source of single propagating microwaves photons. Working in the context of a quantum network, nodes are connected via propagating, nonclassical states of the electromagnetic field. As such, preparing and detecting propagating quantum states is an essential task. I work with one particular node consisting of a microfabricated, effective two level system coupled to a microwave resonator and study its ability to produce propagating nonclassical states, such as single photon states. In principle, states generated by this node could be sent to other such nodes. However, I send them into a Josephson parametric amplifier (JPA) to characterize the source. In particular, I discuss how to design and couple the two components that form my source: a fixed frequency transmon qubit and a 3D superconducting waveguide cavity. I demonstrate the ability to control of the dynamics of this combined system and implement a single photon generation protocol, which utilizes a single microwave control field that is far detuned from the photon emission frequency. To characterize the generation, I perform tomography on the propagating photon state to determine its density matrix ρ. I perform repeated JPA-backed, linear measurements of the propagating state. Based on the histograms of my measurements, I infer a maximum single photon component ρ11 = 0:36 ± 0:01. I characterize the imperfections of the photon generation and detection, including detection inefficiency and measurement backaction. I find that within uncertainty my measurements match my expectation

Comparison of the anaerobic microbiota of deep-water Geodia spp. and sandy sediments in the Straits of Florida

Marine sediments and sponges may show steep variations in redox potential, providing niches for both aerobic and anaerobic microorganisms. Geodia spp. and sediment specimens from the Straits of Florida were fixed using paraformaldehyde and 95% ethanol (v/v) for fluorescence in situ hybridization (FISH). In addition, homogenates of sponge and sediment samples were incubated anaerobically on various cysteine supplemented agars. FISH analysis showed a prominent similarity of microbiota in sediments and Geodia spp. samples. Furthermore, the presence of sulfate-reducing and annamox bacteria as well as other obligate anaerobic microorganisms in both Geodia spp. and sediment samples were also confirmed. Anaerobic cultures obtained from the homogenates allowed the isolation of a variety of facultative anaerobes, primarily Bacillus spp. and Vibrio spp. Obligate anaerobes such as Desulfovibrio spp. and Clostridium spp. were also found. We also provide the first evidence for a culturable marine member of the Chloroflexi, which may enter into symbiotic relationships with deep-water sponges such as Geodia spp. Resuspended sediment particles, may provide a source of microorganisms able to associate or form a symbiotic relationship with sponges. © 2010 International Society for Microbial Ecology All rights reserved