Optimized Noise Suppression for Quantum Circuits

Quantum computation promises to advance a wide range of computational tasks. However, current quantum hardware suffers from noise and is too small for error correction. Thus, accurately utilizing noisy quantum computers strongly relies on noise characterization, mitigation, and suppression. Crucially, these methods must also be efficient in terms of their classical and quantum overhead. Here, we efficiently characterize and mitigate crosstalk noise, which is a severe error source in, e.g., cross-resonance based superconducting quantum processors. For crosstalk characterization, we develop a simplified measurement experiment. Furthermore, we analyze the problem of optimal experiment scheduling and solve it for common hardware architectures. After characterization, we mitigate noise in quantum circuits by a noise-aware qubit routing algorithm. Our integer programming algorithm extends previous work on optimized qubit routing by swap insertion. We incorporate the measured crosstalk errors in addition to other, more easily accessible noise data in the objective function. Furthermore, we strengthen the underlying integer linear model by proving a convex hull result about an associated class of polytopes, which has applications beyond this work. We evaluate the proposed method by characterizing crosstalk noise for a complete 27 qubit chip and leverage the resulting data to improve the approximation ratio of the Quantum Approximate Optimization Algorithm by up to 10 % compared to other established noise-aware routing methods. Our work clearly demonstrates the gains of including noise data when mapping abstract quantum circuits to hardware native ones

Empathy: A clue for prosocialty and driver of indirect reciprocity.

Indirect reciprocity has been proposed to explain prosocial behavior among strangers, whereby the prosocial act is returned by a third party. However, what happens if the prosocial act cannot be observed by the third party? Here, we examine whether empathy serves as a clue for prosociality and whether people are more generous toward more empathetic people. In a laboratory study, we measured prosocial behavior as the amount sent in the dictator game and empathy based on the Interpersonal Reactivity Index (IRI). By using an incentivized task, we find that people believe that more empathetic participants send more money in the dictator game. Thus, people see empathy as a clue for prosocial behavior. Furthermore, in a second dictator game, participants indirectly reciprocate by sending more money to more empathetic recipients. Therefore, we suggest that empathy can replace a reputation derived from observable prosocial behavior in triggering indirect reciprocity

Penalty contracts: is it all about paying the cash upfront?

We experimentally investigate the relevance of a cash upfront payment for the effort-enhancing effect of penalty contracts. We find that penalty contracts where participants receive the upfront payment physically before working on a real effort task induce more effort than penalty contracts where participants are only informed about the upfront payment. When comparing penalty contracts with economically-equivalent bonus contracts, we find that penalty contracts lead to higher effort provision than bonus contracts, but only if participants physically receive the upfront cash payment in advance. We suggest that the higher salience of the cash upfront payment might be a core driver of the detected framing effect. Our findings emphasize the importance of experimental design choices when studying framed incentive contracts

Do patients with gastroesophageal reflux disease and somatoform tendencies benefit from antireflux surgery?

Source at http://dx.doi.org/10.3748/wjg.v25.i3.388.BACKGROUND - The clinical presentation of gastroesophageal reflux disease (GERD) shows a large symptom variation also in different intensities among patients. As several studies have shown, there is a large overlap in the symptomatic spectrum between proven GERD and other disorders such as dyspepsia, functional heartburn and/or somatoform disorders. AIM - To prospectively evaluate the GERD patients with and without somatoform disorders before and after laparoscopic antireflux surgery. METHODS - In a tertiary referral center for foregut surgery over a period of 3 years patients with GERD, qualifying for the indication of laparoscopic antireflux surgery, were investigated prospectively regarding their symptomatic spectrum in order to identify GERD and associated somatoform disorders. Assessment of symptoms was performed by an instrument for the evaluation of somatoform disorders [Somatoform Symptom Index (SSI) > 17]. Quality of life was evaluated by Gastrointestinal Quality of Life Index (GIQLI). RESULTS - In 123 patients an indication for laparoscopic antireflux surgery was established and in 43 patients further medical therapy was suggested. The portion of somatoform tendencies in the total patient population was 20.48% (34 patients). Patients with a positive SSI had a preoperative GIQLI of 77 (32-111). Patients with a normal SSI had a GIQLI of 105 (29-140) (P P < 0.0043). CONCLUSION - Patients with GERD and associated somatoform disorders have significantly worse levels of quality of life. The latter patients can also benefit from laparoscopic fundoplication, however they will not reach a normal level

Intrathecal B-cell accumulation and axonal damage distinguish MRI-based benign from aggressive onset in MS

Objective We explored the incremental value of adding multiple disease activity biomarkers in CSF and serum for distinguishing MRI-based benign from aggressive MS in early disease course. Methods Ninety-three patients diagnosed with clinically isolated syndrome (CIS) or early MS were divided into 3 nonoverlapping severity groups defined by objective MRI criteria. Ninety-seven patients with noninflammatory neurologic disorders and 48 patients with other inflammatory neurologic diseases served as controls. Leukocyte subsets in the CSF were analyzed by flow cytometry. CSF neurofilament light chain (NfL) and chitinase-3-like protein 1 (CHI3L1) levels were measured by ELISA. Serum NfL levels were examined using single molecule array technology. Results CSF CD20+/CD14+ ratios and NfL levels in CSF and serum were significantly different between high and low MRI severity groups, whereas no difference was found for CSF CHI3L1 levels. NfL levels in CSF and serum highly correlated. Receiver operating characteristic analysis demonstrated that the cumulative sums combining CSF CD20+/CD14+ ratios and NfL levels in serum or CSF considerably improved diagnostic accuracy. A composite score built from these 2 cumulative sums best distinguished MRI severity. These findings were validated by support vector machine analysis, which confirmed that the accuracy of the cumulative sums and composite score outperforms single biomarkers. Conclusion Patients with extreme manifestations of CIS or early MS defined by strict MRI parameters can be best distinguished by combining markers of intrathecal B-cell accumulation and axonal damage. This could stratify individual treatment decisions toward a more personalized immunotherapy

Environmental Factors Affecting the Expression of pilAB as Well as the Proteome and Transcriptome of the Grass Endophyte Azoarcus sp. Strain BH72

gene encoding the structural protein of type IV pili that are essential for plant colonization appears to be regulated in a population density-dependent manner.. The expression of one of them was shown to be induced in plant roots. sp. to analyze mechanisms and molecules involved in the population-dependent gene expression in this endophyte in future

Open Power System Data - Frictionless data for electricity system modelling

The quality of electricity system modelling heavily depends on the input data used. Although a lot of data is publicly available, it is often dispersed, tedious to process and partly contains errors. We argue that a central provision of input data for modelling has the character of a public good: it reduces overall societal costs for quantitative energy research as redundant work is avoided, and it improves transparency and reproducibility in electricity system modelling. This paper describes the Open Power System Data platform that aims at realising the efficiency and quality gains of centralised data provision by collecting, checking, processing, aggregating, documenting and publishing data required by most modellers. We conclude that the platform can provide substantial benefits to energy system analysis by raising efficiency of data pre-processing, providing a method for making data pre-processing for energy system modelling traceable, flexible and reproducible and improving the quality of original data published by data providers.Comment: This is the postprint version of the articl

Atrial Natriuretic Peptide Induces Postprandial Lipid Oxidation in Humans

OBJECTIVE—Atrial natriuretic peptide (ANP) regulates arterial blood pressure. In addition, ANP has recently been shown to promote human adipose tissue lipolysis through cGMP-mediated hormone-sensitive lipase activation. We hypothesized that ANP increases postprandial free fatty acid (FFA) availability and energy expenditure while decreasing arterial blood pressure

Macrophages and glia are the dominant P2X7-expressing cell types in the gut nervous system—No evidence for the role of neuronal P2X7 receptors in colitis

The blockade or deletion of the pro-inflammatory P2X7 receptor channel has been shown to reduce tissue damage and symptoms in models of inflammatory bowel disease, and P2X7 receptors on enteric neurons were suggested to mediate neuronal death and associated motility changes. Here, we used P2X7-specific antibodies and nanobodies, as well as a bacterial artificial chromosome transgenic P2X7-EGFP reporter mouse model and P2rx7$^{-/-}$ controls to perform a detailed analysis of cell type-specific P2X7 expression and possible overexpression effects in the enteric nervous system of the distal colon. In contrast to previous studies, we did not detect P2X7 in neurons but found dominant expression in glia and macrophages, which closely interact with the neurons. The overexpression of P2X7 per se did not induce significant pathological effects. Our data indicate that macrophages and/or glia account for P2X7-mediated neuronal damage in inflammatory bowel disease and provide a refined basis for the exploration of P2X7-based therapeutic strategies