Engineering adiabaticity at an avoided crossing with optimal control

We investigate ways to optimize adiabaticity and diabaticity in the Landau-Zener model with non-uniform sweeps. We show how diabaticity can be engineered with a pulse consisting of a linear sweep augmented by an oscillating term. We show that the oscillation leads to jumps in populations whose value can be accurately modeled using a model of multiple, photon-assisted Landau-Zener transitions, which generalizes work by Wubs et al. [New J. Phys. 7, 218 (2005)]. We extend the study on diabaticity using methods derived from optimal control. We also show how to preserve adiabaticity with optimal pulses at limited time, finding a non-uniform quantum speed limit

Wie geht es weiter mit der statistischen Auswertung der Funkstörungen von Seriengeräten? Das Projekt EN 50715

Da eine 100%-Kontrolle der Funkentstörung von Geräten wegen des Zeitaufwandes nicht möglich ist, kann eine Bewertung der Konformität einer ganzen Serie nur mit Hilfe der Untersuchung einer begrenzten Stichprobe mittels statistischer Methoden erfolgen. Die Grundlagen dazu sind in CISPR TR 16-4-3 [1] zu finden. Schon in den ersten CISPR-Normen zur Funkentstörung wurde folgendes zur Signifikanz eines CISPR-Grenzwertes festgelegt: „Die Bedeutung der Grenzwerte bei typgeprüften Geräten muss sein, dass auf statistischer Grundlage bei seriengefertigten Geräten mindestens 80% der Geräte mit einer Sicherheit von mindestens 80% die Grenzwerte einhalten.“ Umgangssprachlich wird das als 80/80-Regel bezeichnet. Bei der Entwicklung der Grenzwerte wurde dies bereits berücksichtigt und die Grenzwerte entsprechend verschärft. In CISPR TR 16-4-3 und den Produktnormen zur Funkentstörung wie CISPR 11, CISPR 14.1 und CISPR 15 wurden von Anfang an folgende Methoden verwendet: • Prüfung auf der Basis der nichtzentralen t-Verteilung (allgemein 5 Geräte), • Prüfung auf der Basis der Binomial-Verteilung (mindestens 7 Geräte). Später wurde von den Autoren dieses Beitrags noch eine weitere Methode entwickelt und in die Normung aufgenommen, die in der Praxis besonders einfach anwendbar ist: • Prüfung auf der Basis eines allgemeinen Abstands zum Grenzwert (allgemein 5 Geräte). Alle 3 Methoden haben sich in der Praxis über viele Jahre bewährt

An integrated tool-set for Control, Calibration and Characterization of quantum devices applied to superconducting qubits

Efforts to scale-up quantum computation have reached a point where the principal limiting factor is not the number of qubits, but the entangling gate infidelity. However, a highly detailed system characterization required to understand the underlying errors is an arduous process and impractical with increasing chip size. Open-loop optimal control techniques allow for the improvement of gates but are limited by the models they are based on. To rectify the situation, we provide a new integrated open-source tool-set for Control, Calibration and Characterization ($C^3$), capable of open-loop pulse optimization, model-free calibration, model fitting and refinement. We present a methodology to combine these tools to find a quantitatively accurate system model, high-fidelity gates and an approximate error budget, all based on a high-performance, feature-rich simulator. We illustrate our methods using fixed-frequency superconducting qubits for which we learn model parameters to an accuracy of $<1\%$ and derive a coherence limited cross-resonance (CR) gate that achieves $99.6\%$ fidelity without need for calibration.Comment: Source code available at http://q-optimize.org; added reference

Use and caregiver-reported efficacy of medical cannabis in children and adolescents in Switzerland.

Evidence on the use and efficacy of medical cannabis for children is limited. We examined clinical and epidemiological characteristics of medical cannabis treatment and caregiver-reported effects in children and adolescents in Switzerland. We collected clinical data from children and adolescents (< 18 years) who received Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), or a combination of the two between 2008 and 2019 in Switzerland. Out of 205 contacted families, 90 agreed to participate. The median age at the first prescription was 11.5 years (interquartile range (IQR) 6-16), and 32 patients were female (36%). Fifty-one (57%) patients received CBD only and 39 (43%) THC. Patients were more likely to receive THC therapy if one of the following symptoms or signs were present: spasticity, pain, lack of weight gain, vomiting, or nausea, whereas seizures were the dominant indication for CBD therapy. Improvements were reported in 59 (66%) study participants. The largest treatment effects were reported for pain, spasticity, and frequency of seizures in participants treated with THC, and for those treated with pure CBD, the frequency of seizures. However, 43% of caregivers reported treatment interruptions, mainly because of lack of improvement (56%), side effects (46%), the need for a gastric tube (44%), and cost considerations (23%).Conclusions: The effects of medical cannabis in children and adolescents with chronic conditions are unknown except for rare seizure disorders, but the caregiver-reported data analysed here may justify trials of medical cannabis with standardized concentrations of THC or CBD to assess its efficacy in the young. What is Known: • The use of medical cannabis (THC and CBD) to treat a variety of diseases among children and adolescents is increasing. • In contrast to adults, there is no evidence to support the use of medical cannabis to treat chronic pain and spasticity in children, but substantial evidence to support the use of CBD in children with rare seizure disorders. What is New: • This study provides important insights into prescription practices, dosages, and treatment outcomes in children and adolescents using medical cannabis data from a real-life setting. • The effects of medical cannabis in children and adolescents with chronic conditions shown in our study support trials of medical cannabis for chronic conditions

Children's perceptions of parental emotional neglect and control and psychopathology

&lt;b&gt;Background:&lt;/b&gt; Parental emotional neglect is linked to psychiatric disorder. This study explores the associations between children’s perceptions of parental emotional neglect and future psychopathology. &lt;b&gt;Methods:&lt;/b&gt; In a school-based longitudinal study of nearly 1700 children aged 11-15 we explored children’s perceptions of parenting, as measured by the parental bonding instrument (PBI) at age 11, and their associations with later psychiatric diagnosis at age 15, as measured by computerized psychiatric interview. Rather than using the traditional four category approach to the PBI, we identified groups of children, classified according to their perceptions of parenting, using latent class analysis. &lt;b&gt;Results:&lt;/b&gt; A small group of children (3%) perceived their parents as almost always emotionally neglectful and controlling. This group had an increased odds of psychiatric disorder (OR 2.14; 95% CI 1.29-4.50), increased overall (standardised) psychiatric symptom scores (B = 0.46; 95% CI 0.16-0.75) and increased scores in all psychiatric subscales except substance-use at age 15, despite no increase in psychiatric referral at age 11. Analyses controlled for key potential confounders (e.g. socioeconomic status). &lt;b&gt;Conclusions:&lt;/b&gt; Although our findings are limited by having no objective evidence that children’s perceptions of emotional neglect are directly associated with actual neglect, children’s perceptions of neglect and control are associated with over twice the odds of psychiatric disorder at age 15. Children’s perceptions that parents are emotionally neglectful and controlling are independently associated with later psychiatric disorder and should be taken seriously as a risk factor for future psychopathology