Demonstrating a superconducting dual-rail cavity qubit with erasure-detected logical measurements

A critical challenge in developing scalable error-corrected quantum systems is the accumulation of errors while performing operations and measurements. One promising approach is to design a system where errors can be detected and converted into erasures. A recent proposal aims to do this using a dual-rail encoding with superconducting cavities. In this work, we implement such a dual-rail cavity qubit and use it to demonstrate a projective logical measurement with erasure detection. We measure logical state preparation and measurement errors at the $0.01\%$-level and detect over $99\%$ of cavity decay events as erasures. We use the precision of this new measurement protocol to distinguish different types of errors in this system, finding that while decay errors occur with probability $\sim 0.2\%$ per microsecond, phase errors occur 6 times less frequently and bit flips occur at least 170 times less frequently. These findings represent the first confirmation of the expected error hierarchy necessary to concatenate dual-rail erasure qubits into a highly efficient erasure code

Sugar-cane juice clarification for sirup manufacture /

no.921 (1920

Mechanical reinforcement in a polyisoprene rubber by hybrid nanofillers

Melt blending of hybrid nanofillers with rubber matrices could make rubber nanocomposites more attractive for industrial applications. In this work, the low-amplitude dynamic shear modulus of polyisoprene rubber filled with carbon nanotubes or nano-graphite, individually or in combination with carbon black, was measured. A rationalisation of the results highlighted interactive effects of carbon allotropes on the mechanical reinforcement of rubber nanocomposites. The filler–matrix interfacial area was identified as a parameter able to correlate the moduli values of different fillers, by reducing them to a common master curve

Error-Detectable Bosonic Entangling Gates with a Noisy Ancilla

Bosonic quantum error correction has proven to be a successful approach for extending the coherence of quantum memories, but to execute deep quantum circuits, high-fidelity gates between encoded qubits are needed. To that end, we present a family of error-detectable two-qubit gates for a variety of bosonic encodings. From a new geometric framework based on a “Bloch sphere” of bosonic operators, we construct ZZ_{L}(θ) and exponential-swap(θ) gates for the binomial, four-legged cat, dual-rail, and several other bosonic codes. The gate Hamiltonian is simple to engineer, requiring only a programmable beam splitter between two bosonic qubits and an ancilla dispersively coupled to one qubit. This Hamiltonian can be realized in circuit QED hardware with ancilla transmons and microwave cavities. The proposed theoretical framework was developed for circuit QED but is generalizable to any platform that can effectively generate this Hamiltonian. Crucially, one can also detect first-order errors in the ancilla and the bosonic qubits during the gates. We show that this allows one to reach error-detected gate fidelities at the 0.01% level with today’s hardware, limited only by second-order hardware errors

A 24 Milligram Bimodal Release Ondansetron Pill (RHB-102) Shows No Evidence of QT Interval Prolongation

Background: Ondansetron is first line treatment for vomiting and one of the most common medications in the ED setting. Concerns over the 32mg IV dose association with prolonged corrected QT interval (QTc) and torsades de pointes prompted an FDA warning in 2011. Still, there is a paucity of prospective data evaluating lower dose ondansetron in the acute care setting. As part of a double blind, placebo-controlled trial of a 24 mg bimodal release ondansetron (BRO) pill, we tested the safety of BRO compared to placebo on QTc change. The safety outcomes included either an increase in mean QTc or an increase in the proportion of patients with QTc change \u3e 30 msec. Methods: This was a planned safety outcome analysis within a multi-center, double blind, placebo-controlled trial. The trial compared the effects of BRO among patients â%o¥ 12 years, who presented to 19 EDs and 2 urgent-care centers with symptoms of acute gastroenteritis. The BRO provides early serum levels similar to an 8mg immediate release ondansetron tablet with sustained levels over 24 hours. Exclusion criteria were CHF, uncontrolled diabetes, recent surgery, alcohol and substance abuse, and a baseline EKG QTc\u3e 450ms. The safety endpoint for this analysis was the change in QTc interval at 4 hours following administration of study drug compared to baseline QTc. We calculated each QTc using both Bazett’s (QTcB) and Fredericia’s (QTcF) formulas. Statistical analyses included Chi Square and student’s t-test methods. Results: There were 156 patients who had ECG testing within the overall trial. The mean baseline QTcB in the BRO and placebo arms were 429.9 and 423.5 msec respectively. There was no difference in the change in QTcB at 4 hours post-study drug administration between the BRO (+1.1, 95% CI -2.9 to 5.2 msec) and placebo group (+4.4, 95% CI -0.2 to 9.0 msec). There was similarly no difference using the QTcF calculation. There were 4 (4.4%) patients in the BRO arm with a QTcB change \u3e 30 msec vs. 4 (7.1%) in the placebo arm (p=0.48). No patients in either arm had a QTcB change \u3e 60 msec after study drug administration. Conclusion: In patients with normal baseline QTc, bimodal extended release ondansetron caused no QTc prolongation in comparison to placebo. This supports previous post-marketing safety data for the currently available single dose short-acting oral formulation among patients without risk factors