483 research outputs found
Atomic layer deposition of titanium nitride for quantum circuits
Superconducting thin films with high intrinsic kinetic inductance are of
great importance for photon detectors, achieving strong coupling in hybrid
systems, and protected qubits. We report on the performance of titanium nitride
resonators, patterned on thin films (9-110 nm) grown by atomic layer
deposition, with sheet inductances of up to 234 pH/square. For films thicker
than 14 nm, quality factors measured in the quantum regime range from 0.4 to
1.0 million and are likely limited by dielectric two-level systems.
Additionally, we show characteristic impedances up to 28 kOhm, with no
significant degradation of the internal quality factor as the impedance
increases. These high impedances correspond to an increased single photon
coupling strength of 24 times compared to a 50 Ohm resonator, transformative
for hybrid quantum systems and quantum sensing.Comment: 10 pages, 8 figures including supplemental material
Magnetic resonance imaging correlates of neuro-axonal pathology in the MS spinal cord.
In people with multiple sclerosis (MS), the spinal cord is the structure most commonly affected by clinically detectable pathology at presentation, and a key part of the central nervous system involved in chronic disease deterioration. Indices, such as the spinal cord cross-sectional area at the level C2 have been developed as tools to predict future disability, and-by inference-axonal loss. However, this and other histo-pathological correlates of spinal cord magnetic resonance imaging (MRI) changes in MS remain incompletely understood. In recent years, there has been a surge of interest in developing quantitative MRI tools to measure specific tissue features, including axonal density, myelin content, neurite density, and orientation, among others, with an emphasis on the spinal cord. Quantitative MRI techniques including T1 and T2 , magnetization transfer and a number of diffusion-derived indices have all been applied to MS spinal cord. Particularly diffusion-based MRI techniques combined with microscopic resolution achievable using high magnetic field scanners enable a new level of anatomical detail and quantification of indices that are clinically meaningful.Barts Charity (grants # 468/1506 & G‐001109
Quantum Fields on the Groenewold-Moyal Plane
We give an introductory review of quantum physics on the noncommutative
spacetime called the Groenewold-Moyal plane. Basic ideas like star products,
twisted statistics, second quantized fields and discrete symmetries are
discussed. We also outline some of the recent developments in these fields and
mention where one can search for experimental signals.Comment: 50 pages, 3 figures. v2: published versio
Tegaserod Treatment for Dysmotility-Like Functional Dyspepsia: Results of Two Randomized, Controlled Trials
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74639/1/j.1572-0241.2008.01953.x.pd
Hierarchically coupled ultradian oscillators generating robust circadian rhythms
Ensembles of mutually coupled ultradian cellular oscillators have been proposed by a number of authors to explain the generation of circadian rhythms in mammals. Most mathematical models using many coupled oscillators predict that the output period should vary as the square root of the number of participating units, thus being inconsistent with the well-established experimental result that ablation of substantial parts of the suprachiasmatic nuclei (SCN), the main circadian pacemaker in mammals, does not eliminate the overt circadian functions, which show no changes in the phases or periods of the rhythms. From these observations, we have developed a theoretical model that exhibits the robustness of the circadian clock to changes in the number of cells in the SCN, and that is readily adaptable to include the successful features of other known models of circadian regulation, such as the phase response curves and light resetting of the phase
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