81 research outputs found
Fundamental thresholds of realistic quantum error correction circuits from classical spin models
Mapping the decoding of quantum error correcting (QEC) codes to classical disordered statistical mechanics models allows one to determine critical error thresholds of QEC codes under phenomenological noise models. Here, we extend this mapping to admit realistic, multi-parameter noise models of faulty QEC circuits, derive the associated strongly correlated classical spin models, and illustrate this approach for a quantum repetition code with faulty stabilizer readout circuits. We use Monte-Carlo simulations to study the resulting phase diagram and benchmark our results against a minimum-weight perfect matching decoder. The presented method provides an avenue to assess fundamental thresholds of QEC circuits, independent of specific decoding strategies, and can thereby help guiding the development of near-term QEC hardware
Towards a realistic GaAs-spin qubit device for a classical error-corrected quantum memory
Based on numerically-optimized real-device gates and parameters we study the
performance of the phase-flip (repetition) code on a linear array of Gallium
Arsenide (GaAs) quantum dots hosting singlet-triplet qubits. We first examine
the expected performance of the code using simple error models of circuit-level
and phenomenological noise, reporting, for example, a circuit-level
depolarizing noise threshold of approximately 3%. We then perform
density-matrix simulations using a maximum-likelihood and minimum-weight
matching decoder to study the effect of real-device dephasing, read-out error,
quasi-static as well as fast gate noise. Considering the trade-off between
qubit read-out error and dephasing time (T2) over measurement time, we identify
a sub-threshold region for the phase-flip code which lies within experimental
reach.Comment: 22 page
The role of multi-slice computed tomography in stable angina management: a current perspective
Contrast-enhanced CT coronary angiography (CTCA) has evolved as a reliable alternative imaging modality technique and may be the preferred initial diagnostic test in patients with stable angina with intermediate pre-test probability of CAD. However, because CTCA is moderately predictive for indicating the functional significance of a lesion, the combination of anatomic and functional imaging will become increasingly important. The technology will continue to improve with better spatial and temporal resolution at low radiation exposure, and CTCA may eventually replace invasive coronary angiography. The establishment of the precise role of CTCA in the diagnosis and management of patients with stable angina requires high-quality randomised study designs with clinical outcomes as a primary outcome
Towards a greater dialogue on disability between Muslims and Christians
Attitudes to disability and disabled people by Muslims – focusing on attitudes in the Middle East and North Africa - and Christians – focusing on the West (here taken to mean Europe, North America and Australasia) - were examined through a grounded theory literature search, with the study being divided into three phases of reading and analysis. The aims of study were to develop a dialogue on disability between the two cultures, to inform an understanding of the attitudes to disability in the two cultures, and to inform cultural practice in promoting support and equality in both cultures. The study finds that Islam and Christianity have much in common and are a force for good in promoting and developing disability equality in both Muslim and Christian cultures
A change in the air? The role of offshore wind in Australia’s transition to a 100 % renewable grid
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