We present details and results for a superconducting quantum bit (qubit) design in which a tunable flux qubit is coupled strongly to a transmission line. Quantum information storage in the transmission line is demonstrated with a dephasing time of T(2)∼ 2.5 µs. However, energy lifetimes of the qubit are found to be short (∼ 10 ns) and not consistent with predictions. Several design and material changes do not affect qubit coherence times. In order to determine the cause of these short coherence times, we fabricated standard flux qubits based on a design which was previously successfully used by others. Initial results show significantly improved coherence times, possibly implicating losses associated with the large size of our qubit.
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http://dx.doi.org/10.1088/0953-8984/22/5/053201 | DOI Listing |
Ann N Y Acad Sci
January 2025
Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
People enjoy engaging with music. Live music concerts provide an excellent option to investigate real-world music experiences, and at the same time, use neurophysiological synchrony to assess dynamic engagement. In the current study, we assessed engagement in a live concert setting using synchrony of cardiorespiratory measures, comparing inter-subject, stimulus-response, correlation, and phase coherence.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Trinity Biomedical Sciences Institute, Trinity College Dublin, University of Dublin, Dublin, Dublin 2, Ireland.
Background: Amyotrophic lateral sclerosis (ALS) shares pathological and genetic underpinnings with frontotemporal dementia (FTD). ALS manifests with diverse symptoms, including progressive neuro-motor degeneration, muscle weakness, but also cognitive-behavioural changes in up to half of the cases. Resting-state EEG measures, particularly spectral power and functional connectivity, have been instrumental for discerning abnormal motor and cognitive network function in ALS [1]-[3].
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Google Quantum AI, Santa Barbara, California 93117, USA.
Quantum error correction (QEC) provides a practical path to fault-tolerant quantum computing through scaling to large qubit numbers, assuming that physical errors are sufficiently uncorrelated in time and space. In superconducting qubit arrays, high-energy impact events can produce correlated errors, violating this key assumption. Following such an event, phonons with energy above the superconducting gap propagate throughout the device substrate, which in turn generate a temporary surge in quasiparticle (QP) density throughout the array.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, C.P. 04510 Mexico City, Mexico.
Quantum chaos has recently received increasing attention due to its relationship with experimental and theoretical studies of nonequilibrium quantum dynamics, thermalization, and the scrambling of quantum information. In an isolated system, quantum chaos refers to properties of the spectrum that emerge when the classical counterpart of the system is chaotic. However, despite experimental progress leading to longer coherence times, interactions with an environment can never be neglected, which calls for a definition of quantum chaos in dissipative systems.
View Article and Find Full Text PDFPurpose: To explore how serum diabetes autoantibodies are related to the development of early diabetic retinopathy in children with type 1 diabetes mellitus.
Methods: In this prospective and observational study, 62 patients with type 1 diabetes mellitus who had not yet developed clinical diabetic retinopathy were followed up for at least 5 years. Healthy volunteers aged 10 to 20 years were also included.
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