Massively parallel quantum computer simulator, eleven years later

A revised version of the massively parallel simulator of a universal quantum computer, described in this journal eleven years ago, is used to benchmark various gate-based quantum algorithms on some of the most powerful supercomputers that exist today. Adaptive encoding of the wave function reduces the memory requirement by a factor of eight, making it possible to simulate universal quantum computers with up to 48 qubits on the Sunway TaihuLight and on the K computer. The simulator exhibits close-to-ideal weak-scaling behavior on the Sunway TaihuLight,on the K computer, on an IBM Blue Gene/Q, and on Intel Xeon based clusters, implying that the combination of parallelization and hardware can track the exponential scaling due to the increasing number of qubits. Results of executing simple quantum circuits and Shor's factorization algorithm on quantum computers containing up to 48 qubits are presented.Comment: Substantially rewritten + new data. Published in Computer Physics Communicatio

Gate-error analysis in simulations of quantum computers with transmon qubits

In the model of gate-based quantum computation, the qubits are controlled by a sequence of quantum gates. In superconducting qubit systems, these gates can be implemented by voltage pulses. The success of implementing a particular gate can be expressed by various metrics such as the average gate fidelity, the diamond distance, and the unitarity. We analyze these metrics of gate pulses for a system of two superconducting transmon qubits coupled by a resonator, a system inspired by the architecture of the IBM Quantum Experience. The metrics are obtained by numerical solution of the time-dependent Schr\"odinger equation of the transmon system. We find that the metrics reflect systematic errors that are most pronounced for echoed cross-resonance gates, but that none of the studied metrics can reliably predict the performance of a gate when used repeatedly in a quantum algorithm

Ariel - Volume 2 Number 2

Editors Delvyn C. Case, Jr. Paul M. Fernhoff News Editors Richard Bonanno Daniel B. Gould Ronald A. Hoffman Lay-Out Editor Carol Dolinskas Sports Editor James J. Nocon Contributing Editors MichaeI J. Blecker Lin Sey Edwards Jack Guralnik W. Cherry Light Features Editor Donald A. Bergman Stephen P. Flynn Business Manager Nick Grego Public Relations Robin A. Edward

Benchmarking gate-based quantum computers

With the advent of public access to small gate-based quantum processors, it becomes necessary to develop a benchmarking methodology such that independent researchers can validate the operation of these processors. We explore the usefulness of a number of simple quantum circuits as benchmarks for gate-based quantum computing devices and show that circuits performing identity operations are very simple, scalable and sensitive to gate errors and are therefore very well suited for this task. We illustrate the procedure by presenting benchmark results for the IBM Quantum Experience, a cloud-based platform for gate-based quantum computing.Comment: Accepted for publication in Computer Physics Communication

Ariel - Volume 1 Number 3

Copyright 1969 Arie

Ariel - Volume 1 Number 2

Copyright 1969 Arie

Ariel - Volume 2 Number 5

Editors Delvyn C. Case, Jr. Paul M. Fernhoff News Editors Richard Bonanno Robin A. Edwards Features Editors Stephen P. Flynn Steven A. Ager Lay-Out Editor Carol Dolinskas Contributing Editors Michael J. Blecker W. Cherry Light Eugenia Miller Lin Sey Edwards Jack Guralnik Tom Williams James Noco

Efficacy and cost-effectiveness of the 13C-urea breath test as the primary diagnostic investigation for the detection of Helicobacter pylori infection compared to invasive and non-invasive diagnostic tests

Background: Helicobacter pylori (H. pylori) is one of the most common bacterial infections in humans. There is a risk factor for gastric or duodenal ulcers, gastric cancer and MALT (Mucosa Associated Lymphoid Tissue)-Lymphomas. There are several invasive and non-invasive methods available for the diagnosis of H. pylori. The 13C-urea breath test is a non-invasive method recommended for monitoring H. pylori eradication therapy. However, this test is not yet used for primary assessment of H. pylori in Germany. Objectives: What are the clinical and health economic benefits of the 13C-urea breath test in the primary assessment of H. pylori compared to other invasive and non-invasive methods? Methods: A systematic literature search including a hand search was performed for studies investigating test criteria and cost-effectiveness of the 13C-urea breath test in comparison to other methods used in the primary assessment of H. pylori. Only studies that directly compared the 13C-urea breath test to other H. pylori-tests were included. For the medical part, biopsy-based tests were used as the gold standard. Results: 30 medical studies are included. Compared to the immunoglobulin G (IgG) test, the sensitivity of the 13C-urea breath test is higher in twelve studies, lower in six studies and one study reports no differences. The specificity is higher in 13 studies, lower in three studies and two studies report no differences. Compared to the stool antigen test, the sensitivity of the 13C-urea breath test is higher in nine studies, lower in three studies and one study reports no difference. The specificity is higher in nine studies, lower in two studies and two studies report no differences. Compared to the urease test, the sensitivity of the 13C-urea breath test is higher in four studies, lower in three studies and four studies report no differences. The specificity is higher in five studies, lower in five studies and one study reports no difference. Compared to histology, the sensitivity of the 13C-urea breath test is higher in one study and lower in two studies. The specificity is higher in two studies and lower in one study. One study each compares the 13C-urea breath test to the 14C-urea breath test and the polymerase chain reaction (PCR) test, respectively, and reports no difference in sensitivity and specificity with the 14C-urea breath test, and lower sensitivity and higher specificity compared to PCR. The statistical significance of these differences is described for six of the 30 studies. Nine health economic evaluations are included in the Health Technology Assessment (HTA) report. Among these studies, the test-and-treat strategy using the 13C-urea breath test is compared to test-and-treat using serology in six analyses and to test and treat using the stool antigen test in three analyses. Thereby, test-and-treat using the breath test is shown to be cost-effective over the serology based strategy in three models and is dominated by a test-and-treat strategy using the stool antigen test in one model. A cost-effectiveness comparison between the urea breath test approach and the empirical antisecretory therapy is carried out in four studies. Of these, two studies report that the strategy using the urea breath test is cost-effective over the empirical antisecretory therapy. In two studies, test-and-treat using the 13C-urea breath test is compared to the empirical eradication therapy and in five studies to endoscopy-based strategies. The breath test approach dominates endoscopy in two studies and is dominated by this strategy in one study. Discussion: All included medical and economic studies are limited to a greater or lesser extent. Additionally, the results of the studies are heterogeneous regarding medical and economic outcomes respectively. Thus, the majority of the medical studies do not report the statistical significance of the differences in sensitivity and specificity. In direct comparisons the 13C- urea breath test shows higher sensitivity and specificity than the IgG and stool antigen tests. In comparison to the urease test, results for sensitivity are inconsistent, and the specificity is slightly higher for the 13C-urea breath test. There are not enough results for comparisons between the 13C-urea breath test and the 14C-urea breath test, histology and PCR to describe tendencies. The included economic studies suggest that the test-and-treat strategy using the 13C-urea breath test is cost-effective compared to test-and-treat using serology as well as empirical antisecretory therapies. Due to a lack of valid studies, it is not possible to assess the breath test approach in comparison to test-and-treat using the stool antigen test and the empirical eradication therapy respectively, regarding the cost-effectiveness. The results of economic analyses comparing test-and-treat using the breath test to endoscopy strategies are too heterogeneous to draw any conclusions. Overall, none of the included economic models is able to completely capture the complexity of managing patients with dyspeptic complaints. Conclusions/Recommendations: Based on available medical and economic studies, there is no sufficient evidence to recommend test and-treat using 13C-urea breath testing for the detection of H. pylori infection as the standard procedure for the management of uninvestigated dyspepsia in the German health care system. In addition, it must be considered that the DVGS guidelines of the Deutsche Gesellschaft für Verdauungs- und Stoffwechselkrankheiten (DVGS) recommend endoscopy based methods for the management of patients with dyspeptic complaints

Resveratrol stimulation of SIRT1 & exogenous delivery of FGF21 mimics metformin's ability to alleviate non-alcoholic fatty liver disease caused by diet-induced obesity

Metformin has been used clinically since 1957 for its efficacy and safety as therapy for type 2 diabetes. Besides ameliorating hyperglycemia without risk of hypoglycemia, metformin also lowers plasma triglyceride levels. Furthermore, a wealth of data shows that metformin facilitates weight loss in mice as well as humans. Due to its numerous metabolic benefits, researchers and clinicians are interested in the possibility of using metformin as treatment to combat obesity and other metabolic disorders such as non-alcoholic fatty liver disease (NAFLD). Despite being the most commonly prescribed anti-diabetic, metformin’s complete mechanism(s) for weight loss or for lowering glucose and lipids remains an enigma. Our studies show that metformin-treated mice exhibited decreased caloric intake, providing a viable mechanism for metformin to bring about weight loss. Intriguingly, we found that metformin induces PRDM16 to promote browning of iWAT and increase expression of thermogenic genes such as UCP1 and DIO2. However, metformin did not appear to increase energy expenditure. It’s possible that metformin’s effect on energy expenditure was masked since energy expenditure measurements were taken when metformin-treated mice were still losing weight and were in a state of negative energy balance. Recently, there has been much attention given to AMPK activators as exercise mimetics. Metformin is known to activate AMPK and similarly brings about many beneficial effects as exercise such as alleviation of obesity-induced NAFLD. SIRT1 stimulation by resveratrol and delivery of exogenous FGF21 mimics metformin’s ability to combat obesity and improve NAFLD. Collectively, these results implicate metformin, resveratrol, and exogenous administration of FGF21 as beneficial therapies for weight loss and amelioration of NAFLD

Profiling the mouse brain endothelial transcriptome in health and disease models reveals a core blood-brain barrier dysfunction module.

Blood vessels in the CNS form a specialized and critical structure, the blood-brain barrier (BBB). We present a resource to understand the molecular mechanisms that regulate BBB function in health and dysfunction during disease. Using endothelial cell enrichment and RNA sequencing, we analyzed the gene expression of endothelial cells in mice, comparing brain endothelial cells with peripheral endothelial cells. We also assessed the regulation of CNS endothelial gene expression in models of stroke, multiple sclerosis, traumatic brain injury and seizure, each having profound BBB disruption. We found that although each is caused by a distinct trigger, they exhibit strikingly similar endothelial gene expression changes during BBB disruption, comprising a core BBB dysfunction module that shifts the CNS endothelial cells into a peripheral endothelial cell-like state. The identification of a common pathway for BBB dysfunction suggests that targeting therapeutic agents to limit it may be effective across multiple neurological disorders