Model-Based Optimization of Superconducting Qubit Readout.

Measurement is an essential component of quantum algorithms, and for superconducting qubits it is often the most error prone. Here, we demonstrate model-based readout optimization achieving low measurement errors while avoiding detrimental side effects. For simultaneous and midcircuit measurements across 17 qubits, we observe 1.5% error per qubit with a 500 ns end-to-end duration and minimal excess reset error from residual resonator photons. We also suppress measurement-induced state transitions achieving a leakage rate limited by natural heating. This technique can scale to hundreds of qubits and be used to enhance the performance of error-correcting codes and near-term applications.

Optimizing quantum gates towards the scale of logical qubits.

A foundational assumption of quantum error correction theory is that quantum gates can be scaled to large processors without exceeding the error-threshold for fault tolerance. Two major challenges that could become fundamental roadblocks are manufacturing high-performance quantum hardware and engineering a control system that can reach its performance limits. The control challenge of scaling quantum gates from small to large processors without degrading performance often maps to non-convex, high-constraint, and time-dynamic control optimization over an exponentially expanding configuration space. Here we report on a control optimization strategy that can scalably overcome the complexity of such problems. We demonstrate it by choreographing the frequency trajectories of 68 frequency-tunable superconducting qubits to execute single- and two-qubit gates while mitigating computational errors. When combined with a comprehensive model of physical errors across our processor, the strategy suppresses physical error rates by ~3.7× compared with the case of no optimization. Furthermore, it is projected to achieve a similar performance advantage on a distance-23 surface code logical qubit with 1057 physical qubits. Our control optimization strategy solves a generic scaling challenge in a way that can be adapted to a variety of quantum operations, algorithms, and computing architectures.

Information scrambling in quantum circuits.

Interactions in quantum systems can spread initially localized quantum information into the exponentially many degrees of freedom of the entire system. Understanding this process, known as quantum scrambling, is key to resolving several open questions in physics. Here, by measuring the time-dependent evolution and fluctuation of out-of-time-order correlators, we experimentally investigate the dynamics of quantum scrambling on a 53-qubit quantum processor. We engineer quantum circuits that distinguish operator spreading and operator entanglement and experimentally observe their respective signatures. We show that whereas operator spreading is captured by an efficient classical model, operator entanglement in idealized circuits requires exponentially scaled computational resources to simulate. These results open the path to studying complex and practically relevant physical observables with near-term quantum processors.

Quantum supremacy using a programmable superconducting processor.

The promise of quantum computers is that certain computational tasks might be executed exponentially faster on a quantum processor than on a classical processor1. A fundamental challenge is to build a high-fidelity processor capable of running quantum algorithms in an exponentially large computational space. Here we report the use of a processor with programmable superconducting qubits2-7 to create quantum states on 53 qubits, corresponding to a computational state-space of dimension 253 (about 1016). Measurements from repeated experiments sample the resulting probability distribution, which we verify using classical simulations. Our Sycamore processor takes about 200 seconds to sample one instance of a quantum circuit a million times-our benchmarks currently indicate that the equivalent task for a state-of-the-art classical supercomputer would take approximately 10,000 years. This dramatic increase in speed compared to all known classical algorithms is an experimental realization of quantum supremacy8-14 for this specific computational task, heralding a much-anticipated computing paradigm.

Feasibility and acceptability of group music therapy vs wait-list control for treatment of patients with long-term depression (the SYNCHRONY trial): study protocol for a randomised controlled trial.

BACKGROUND: Depression is of significant global concern. Despite a range of effective treatment options it is estimated that around one in five diagnosed with an acute depressive episode continue to experience enduring symptoms for more than 2 years. There is evidence for effectiveness of individual music therapy for depression. However, no studies have as yet looked at a group intervention within an NHS context. This study aims to assess the feasibility of conducting a randomised controlled trial of group music therapy for patients with long-term depression (symptom durations of 1 year or longer) within the community. METHODS: This is a single-centre randomised controlled feasibility trial of group music therapy versus wait-list control with a nested process evaluation. Thirty participants will be randomised with unbalanced allocation (20 to receive the intervention immediately, 10 as wait-list controls). Group music therapy will be offered three times per week in a community centre with a focus on songwriting. Data will be collected post-intervention, 3 and 6 months after the intervention finishes. We will examine the feasibility of recruitment processes including identifying the number of eligible participants, participation and retention rates and the intervention in terms of testing components, measuring adherence and estimation of the likely intervention effect. A nested process evaluation will consist of treatment fidelity analysis, exploratory analysis of process measures and end-of-participation interviews with participants and referring staff. DISCUSSION: Whilst group music therapy is an option in some community mental health settings, this will be the first study to examine group music therapy for this particular patient group. We will assess symptoms of depression, acceptability of the intervention and quality of life. We anticipate potential challenges in the recruitment and retention of participants. It is unclear whether offering the intervention three times per week will be acceptable to participants, particularly given participants' enduring symptoms and impact upon motivation. This study will provide data to inform both development of the intervention and to assess and inform the design of a full trial. TRIAL REGISTRATION: ISRCTN.com, ISRCTN18164037 . Registered on 26 September 2016.

Development of the Music Therapy Assessment Tool for Advanced Huntington's Disease: A Pilot Validation Study.

BACKGROUND: Case studies of people with Huntington's disease (HD) report that music therapy provides a range of benefits that may improve quality of life; however, no robust music therapy assessment tools exist for this population. OBJECTIVE: Develop and conduct preliminary psychometric testing of a music therapy assessment tool for patients with advanced HD. METHODS: First, we established content and face validity of the Music Therapy Assessment Tool for Advanced HD (MATA-HD) through focus groups and field testing. Second, we examined psychometric properties of the resulting MATA-HD in terms of its construct validity, internal consistency, and inter-rater and intra-rater reliability over 10 group music therapy sessions with 19 patients. RESULTS: The resulting MATA-HD included a total of 15 items across six subscales (Arousal/Attention, Physical Presentation, Communication, Musical, Cognition, and Psychological/Behavioral). We found good construct validity (r ≥ 0.7) for Mood, Communication Level, Communication Effectiveness, Choice, Social Behavior, Arousal, and Attention items. Cronbach's α of 0.825 indicated good internal consistency across 11 items with a common focus of engagement in therapy. The inter-rater reliability (IRR) Intra-Class Coefficient (ICC) scores averaged 0.65, and a mean intra-rater ICC reliability of 0.68 was obtained. Further training and retesting provided a mean of IRR ICC of 0.7. CONCLUSION: Preliminary data indicate that the MATA-HD is a promising tool for measuring patient responses to music therapy interventions across psychological, physical, social, and communication domains of functioning in patients with advanced HD.

Measuring and Suppressing Quantum State Leakage in a Superconducting Qubit.

Leakage errors occur when a quantum system leaves the two-level qubit subspace. Reducing these errors is critically important for quantum error correction to be viable. To quantify leakage errors, we use randomized benchmarking in conjunction with measurement of the leakage population. We characterize single qubit gates in a superconducting qubit, and by refining our use of derivative reduction by adiabatic gate pulse shaping along with detuning of the pulses, we obtain gate errors consistently below 10^{-3} and leakage rates at the 10^{-5} level. With the control optimized, we find that a significant portion of the remaining leakage is due to incoherent heating of the qubit.

Music therapy with disorders of consciousness: current evidence and emergent evidence-based practice.

Patients with prolonged disorders of consciousness (PDOC) stemming from acquired brain injury present one of the most challenging clinical populations in neurological rehabilitation. Because of the complex clinical presentation of PDOC patients, treatment teams are confronted with many medicolegal, ethical, philosophical, moral, and religious issues in day-to-day care. Accurate diagnosis is of central concern, relying on creative approaches from skilled clinical professionals using combined behavioral and neurophysiological measures. This paper presents the latest evidence for using music as a diagnostic tool with PDOC, including recent developments in music therapy interventions and measurement. We outline standardized clinical protocols and behavioral measures to produce diagnostic outcomes and examine recent research illustrating a range of benefits of music-based methods at behavioral, cardiorespiratory, and cortical levels using video, electrocardiography, and electroencephalography methods. These latest developments are discussed in the context of evidence-based practice in rehabilitation with clinical populations.

Characterization of core clinical phenotypes associated with recurrent proximal 15q25.2 microdeletions.

A recurrent proximal microdeletion at 15q25.2 with an approximate 1.5 megabase smallest region of overlap has recently been reported in seven patients and is proposed to be associated with congenital diaphragmatic hernia (CDH), mild to moderate cognitive deficit, and/or features consistent with Diamond-Blackfan anemia. We report on four further patients and define the core phenotypic features of individuals with this microdeletion to include mild to moderate developmental delay or intellectual disability, postnatal short stature, anemia, and cryptorchidism in males. CDH and structural organ malformations appear to be less frequent associations, as is venous thrombosis. There is no consistent facial dysmorphism. Features novel to our patient group include dextrocardia, obstructive sleep apnea, and cleft lip.

Global use of the WHO pocket book of hospital care for children.

BACKGROUND: Studies in the last decade have identified major deficiencies in the care of seriously ill children in hospitals in developing countries. Effective implementation of clinical guidelines is an important strategy for improving quality of care. In 2005 the World Health Organization produced the Pocket Book of Hospital Care for Children - Guidelines for Management of Common Childhood Illnesses in Rural and District Hospitals with Limited Resources. OBJECTIVE: To determine the worldwide distribution, uptake and use of the WHO Pocket Book of Hospital Care for Children. METHODS: A systematic online and postal survey was conducted to assess coverage and uptake of the Pocket Book in low- and middle-income countries (LMICs). More than 1000 key stakeholders with varied roles and responsibilities for child health in 194 countries were invited to participate. Indicators used to measure implementation of the guidelines included local adaptation, use as standard treatment and incorporation into undergraduate and postgraduate training. RESULTS: Information was gathered from 354 respondents representing 134 countries; these included 98 LMICs and 50 countries with under-5 childhood mortality rates >40 deaths/1000 live births. Sixty-four LMICs (44% of 145 LMICs worldwide) including 42 high-mortality countries (66% of 64 high-mortality countries worldwide) reported at least partial implementation of the Pocket Book. However, uptake remains fragmented within countries. CONCLUSION: More than half of all LMICs with high rates of child mortality have reported use and substantial implementation activities, a considerable achievement given minimal resources available for implementation. Improving the accessibility of the Pocket Book and its implementation tools to health workers, and developing a strategic approach to implementation in each country could improve quality of hospital care for children and support efforts towards achieving the Millennium Development Goal 4 targets.

Changes in the epidemiology of gastroenteritis in a paediatric short stay unit following the introduction of rotavirus immunisation.

AIM: Acute gastroenteritis (AGE) has been a significant component of the clinical load in the short stay unit (SSU) at the Royal Children's Hospital (RCH) since its establishment in 2004. Since the introduction of routine rotavirus immunisation in Australia in 2007 there has been a clinical impression of a substantial reduction in AGE managed in the SSU. This study aimed to examine changes in the epidemiology of AGE in the SSU, and RCH overall, between 2005 and 2009 and explore whether this reflects a change specifically in AGE due to rotavirus. METHODS: Discharge coding data for AGE from all inpatient wards, the SSU and emergency department (ED) at the RCH were examined. Stool virology results for the same period were analysed. RESULTS: Since 2007 there has been a 58% reduction in AGE admissions to the SSU. The median age of patients admitted to the RCH with rotaviral enteritis has increased from 1.3 years to 3.8 years. Presentations to the ED for AGE have fallen from 53 to 34 cases per 1000 attendances between 2004 and 2009, and admission rates from the ED have fallen from 23 to 13% of AGE presentations. Detection rates of rotavirus fell from 13.1 to 6.7% between 2005 and 2009. CONCLUSION: A marked decrease in AGE-related clinical activity and reduction in rotavirus detection at the RCH has occurred since the introduction of routine rotavirus immunisation in Australia. This has significant resource planning implications for units based on short stay models of care.

The complementary role of music therapy in the detection of awareness in disorders of consciousness: an audit of concurrent SMART and MATADOC assessments.

In the behavioural assessment of disorders of consciousness (DOC), best practice is for several different assessment tools to be used to encourage a variety of different responses indicative of awareness. Anecdotal evidence suggests a range of musical stimuli may be particularly effective in eliciting responses to guide the assessment process, although comparative data regarding behavioural domains is lacking. This study examined 42 concurrent records of patients assessed using the Sensory Modality Assessment and Rehabilitation Technique (SMART), and the Music Therapy Assessment Tool for Awareness in Disorders of Consciousness (MATADOC) to explore the relationship between diagnosis and behavioural characteristics of the cohort. Whilst the two tools produced a high level of agreement in diagnostic outcome (Spearman Rho .80), divergent diagnosis and weaker correlations between behavioural response items highlight contrasting sensitivities of the tools. Whilst MATADOC has higher sensitivity within auditory and visual domains relative to SMART, SMART has higher sensitivity in the motor domain. The significant contribution of musical response items in MATADOC, and the tactile response item in SMART, indicates both tools provide unique behavioural data predictive of awareness. Multidisciplinary assessment using SMART and MATADOC provides complementary data contributing to a fuller understanding of a patient's level of awareness.

Community-acquired neonatal and infant sepsis in developing countries: efficacy of WHO's currently recommended antibiotics--systematic review and meta-analysis.

OBJECTIVE: To review the aetiology and antibiotic resistance patterns of community-acquired sepsis in developing countries in infants where no clear focus of infection is clinically identified. To estimate the likely efficacy of WHO's recommended treatment for infant sepsis. DESIGN: A systematic review of the literature describing the aetiology of community-acquired neonatal and infant sepsis in developing countries. Using meta-analytical methods, susceptibility was determined to the antibiotic combinations recommended by WHO: (1) benzylpenicillin/ampicillin and gentamicin, (2) chloramphenicol and benzylpenicillin, and (3) third-generation cephalosporins. RESULTS: 19 studies were identified from 13 countries, with over 4000 blood culture isolates. Among neonates, Staphylococcus aureus, Klebsiella spp. and Escherichia coli accounted for 55% (39-70%) of culture positive sepsis on weighted prevalence. In infants outside the neonatal period, the most prevalent pathogens were S aureus, E coli, Klebsiella spp., Streptococcus pneumoniae and Salmonella spp., which accounted for 59% (26-92%) of culture positive sepsis. For neonates, penicillin/gentamicin had comparable in vitro coverage to third-generation cephalosporins (57% vs. 56%). In older infants (1-12 months), in vitro susceptibility to penicillin/gentamicin, chloramphenicol/penicillin and third-generation cephalosporins was 63%, 47% and 64%, respectively. CONCLUSIONS: The high rate of community-acquired resistant sepsis-especially that caused by Klebsiella spp. and S aureus-is a serious global public health concern. In vitro susceptibility data suggest that third-generation cephalosporins are not more effective in treating sepsis than the currently recommended antibiotics, benzylpenicillin and gentamicin; however, with either regimen a significant proportion of bacteraemia is not covered. Revised recommendations for effective second-line antibiotics in neonatal and infant sepsis in developing countries are urgently needed.

Neurophysiological and behavioral responses to music therapy in vegetative and minimally conscious States.

Assessment of awareness for those with disorders of consciousness is a challenging undertaking, due to the complex presentation of the population. Debate surrounds whether behavioral assessments provide greatest accuracy in diagnosis compared to neuro-imaging methods, and despite developments in both, misdiagnosis rates remain high. Music therapy may be effective in the assessment and rehabilitation with this population due to effects of musical stimuli on arousal, attention, and emotion, irrespective of verbal or motor deficits. However, an evidence base is lacking as to which procedures are most effective. To address this, a neurophysiological and behavioral study was undertaken comparing electroencephalogram (EEG), heart rate variability, respiration, and behavioral responses of 20 healthy subjects with 21 individuals in vegetative or minimally conscious states (VS or MCS). Subjects were presented with live preferred music and improvised music entrained to respiration (procedures typically used in music therapy), recordings of disliked music, white noise, and silence. ANOVA tests indicated a range of significant responses (p ≤ 0.05) across healthy subjects corresponding to arousal and attention in response to preferred music including concurrent increases in respiration rate with globally enhanced EEG power spectra responses (p = 0.05-0.0001) across frequency bandwidths. Whilst physiological responses were heterogeneous across patient cohorts, significant post hoc EEG amplitude increases for stimuli associated with preferred music were found for frontal midline theta in six VS and four MCS subjects, and frontal alpha in three VS and four MCS subjects (p = 0.05-0.0001). Furthermore, behavioral data showed a significantly increased blink rate for preferred music (p = 0.029) within the VS cohort. Two VS cases are presented with concurrent changes (p ≤ 0.05) across measures indicative of discriminatory responses to both music therapy procedures. A third MCS case study is presented highlighting how more sensitive selective attention may distinguish MCS from VS. The findings suggest that further investigation is warranted to explore the use of music therapy for prognostic indicators, and its potential to support neuroplasticity in rehabilitation programs.