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.

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.

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.

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.

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.

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.

First probable Australian cases of human infection with Rickettsia felis (cat-flea typhus).

Human infection with Rickettsia felis has been reported in most parts of the world, and R. felis has recently been confirmed in cat fleas in Western Australia. The clinical presentations of R. typhi and R. felis are similar, and in the past, the incidence of R. felis infection may have been underestimated. We describe the first reported cases of probable human R. felis infection in Australia. Two adults and three children in Victoria contracted a rickettsial disease after exposure to fleas from kittens. Molecular testing of fleas demonstrated the presence of R. felis but not R. typhi.

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.

Saying it in song: music therapy as a carer support intervention.

The burdens experienced by informal caregivers are likely to increase in the context of the UK's ageing demographic, and the movement towards more home-based care for those with long-term, chronic or palliative illnesses. This article combines an overview of our understanding of caregiving and carer support interventions, with an outline of the evidence base for music therapy in palliative care. Case material from the author's experiences of songwriting with a carer is used to provide a practical insight into how this emerging palliative care discipline may have the potential to alleviate carer burden, and enhance wellness. More research to explore the efficacy of music therapy as a carer support intervention is recommended.

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.

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.

Music therapy in palliative care: current perspectives.

As the music therapy profession has developed internationally over the last 25 years, so has its role in palliative care. Music is a highly versatile and dynamic therapeutic modality, lending itself to a variety of music therapy techniques used to benefit both those living with life-threatening illnesses and their family members and caregivers. This article will give a broad overview of the historical roots of music therapy and introduce the techniques that are employed in current practice. By combining a review of mainstream music therapy practice involving musical improvisation, song-writing and receptive/recreational techniques with case material from my own experience, this article aims to highlight the potential music therapy holds as an effective holistic practice for palliative care, whatever the care setting.