Robustly decorrelating errors with mixed quantum gates

Coherent errors in quantum operations are ubiquitous. Whether arising from spurious environmental couplings or errors in control fields, such errors can accumulate rapidly and degrade the performance of a quantum circuit significantly more than an average gate fidelity may indicate. As shown by Hastings [1] and Campbell [2], by replacing the deterministic implementation of a quantum gate with a randomized ensemble of implementations, one can dramatically suppress coherent errors. Our work begins by reformulating the results of Hastings and Campbell as a quantum optimal control problem. We then discuss a family of convex programs able to solve this problem, as well as a set of secondary objectives designed to improve the performance, implementability, and robustness of the resulting mixed quantum gates. Finally, we implement these mixed quantum gates on a superconducting qubit and discuss randomized benchmarking results consistent with a marked reduction in the coherent error. [1] M. B. Hastings, Quantum Information & Computation 17, 488 (2017). [2] E. Campbell, Physical Review A 95, 042306 (2017).

Applied Usage and Performance of Statistical Matching in Bibliometrics: The Comparison of Milestone and Regular Papers With Multiple Measurements of Disruptiveness as an Empirical Example

Controlling for confounding factors is one of the central aspects of quantitative research. While methods like linear regression models are common, their results can be misleading under certain conditions. We demonstrate how statistical matching can be utilized as an alternative that enables the inspection of post-matching balancing. This contribution serves as an empirical demonstration of matching in bibliometrics and discusses advantages and potential pitfalls. We propose matching as an easy-to-use approach in bibliometrics to estimate effects and remove bias. To exemplify matching, we use data about papers published in Physical Review E and a selection classified as milestone papers. We analyze whether milestone papers score higher in terms of a proposed class of indicators for measuring disruptiveness than non-milestone papers. We consider disruption indicators DI1, DI5, DI1n, DI5n and DEP and test which of the disruption indicators performs best, based on the assumption that milestone papers should have higher disruption indicator values than non-milestone papers. Four matching algorithms (propensity score matching (PSM), coarsened exact matching (CEM), entropy balancing (EB) and inverse probability weighting (IPTW)) are compared. We find that CEM and EB perform best regarding covariate balancing and DI5 and DEP are well-performing to evaluate disruptiveness of published papers. Peer Review https://publons.com/publon/10.1162/qss_a_00158

EP.TH.893Virtual Clinic follow-up in Laparoscopic Fundoplication Surgery

Aims There are clinical and financial incentives to reduce follow-up NHS clinics after elective surgery. 55% of our laparoscopic anti-reflux procedures are day-cases procedures. To reduce consultant clinic workload and unnecessary face-to-face patient reviews, we introduced a laparoscopic surgical care practitioner (LSCP) based Virtual Clinic. Methods Patients were telephoned on day 1 and 5 to ensure they were managing their diet without significant post-operative symptoms. This was followed by a Virtual Clinic follow-up at 6-8 weeks, using a universal list of questions and template, and an electronic letter with outcomes recorded. 149 patients underwent laparoscopic fundoplication surgery from September 2016 – May 2018. All follow-up clinics, both virtual and face-to-face, were recorded electronically. These were reviewed, data collected and analysed. Results Between September 2016 – May 2018, 149 patients had laparoscopic fundoplication surgery at our trust with the following clinic outcomes: Conclusions Our LSCP Virtual Clinics discharged 50 out of 149 (33%) patients with no need for face-to-face clinic time, and no detriment to patient care. Those requiring further follow-up were patients who had difficulty managing dietary changes, or experiencing symptoms like dysphagia, often needing physical review and further investigations. Furthermore, patients have expressed high satisfaction with this service. Virtual clinic follow-up is safe, patient-friendly, and reduces both clinical and financial load on NHS outpatient clinics.

682 Pre-clinic mpMRI Prostate for Suspected Localised Significant Prostate Cancer – Incidental Findings and Outcomes

Aim Two week wait pathways demand rapid investigation of patients with suspected prostate cancer. To facilitate this, mpMRI prostate imaging is now routinely organised for patients whom meet specific criteria, without prior physical review by an urologist. We sought to establish what incidental findings were amongst this patient group and whether management was affected. Method All patients referred between 1/4/2019 – 30/4/20 on a suspected prostate cancer pathway to the Leicester General Hospital were included with those coded to have had pre-clinic MRI selected. Results During this period 1487 patients were referred on the pathway of which 482 were coded as having has pre-clinic MRI. 8 patients were excluded due to incorrect coding leaving 474 to be analysed. 121 patients had incidental findings mentioned in the report, of these a higher proportion did not have prostate cancer (69%). There were just 11 (2%) significant findings that required further investigation or intervention. These included colorectal lesions, primary bone lesions, suspected bladder cancers and urinary tract calculi. Of this group 3 patients had prostate cancer. Of note 13% of these patients were noted to have diverticular disease and 6% had herniae noted although none required emergent treatment. In this series 32% of patients were confirmed to have prostate cancer with 67.1% of MRI scan reported as PIRADS 3-5. Conclusions Pre-clinic MRI prostate facilitates rapid investigation for suspected prostate cancer. There is a small chance of establishing a significant incidental finding which is slightly more common in the non-cancer group.

RACIONALIZACIÓN DE LOS PROCESOS EN LA REVISIÓN FÍSICA DE INVENTARIOS EN EL ÁREA DE ALMACENAMIENTO DE PRODUCTOS TERMINADOS GARANTIZANDO LA SEGURIDAD Y SALUD EN EL TRABAJO

The company on which this study was carried out performs a technical review of the inventory once a month, with a level of confidence and accuracy of 100%, although its level of precision is very high, it is necessary to change the how nventory control is being executed, since the current method exposes the operator to unnecessary and infallible risk, which has motivated the operations manager to request a change in the process. However, the process with which the inventory is currently being verified requires more man hours and the payment of overtime to its workers to complete the activity, generating an increase in nominal costs. For this reason, the objective of this work is to optimize the method of operation in the physical review of the inventory, allowing it to improve its effectiveness, reduce nominal costs, execution times and guaranteeing safety and health at work. Therefore, the work was carried out through descriptive applied research, developing strategies that start from theories, in order to apply them and thus give an optimal solution to the problems found in the company. Likewise, a quantitative investigation was implemented where the data emerged from a field work carried out in the finished product storage area, through a study of times and movements in the inventory review. Additionally, a cost analysis was carried out, accompanied by various simulations that made it possible to establish which is the appropriate machinery for the process. As a result, it was determined that the drone and the zigzag method is the optimal solution for the physical review of inventory by reducing risks, costs and execution times.