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Your search keyword '"Wilkinson, J. M."' showing total 623 results
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623 results on '"Wilkinson, J. M."'

1. Ubiquitous Spin Freezing in the Superconducting State of UTe2

Author

Sundar, Shyam, Azari, N., Goeks, M., Gheidi, S., Abedi, M., Yakovlev, M., Dunsiger, S. R., Wilkinson, J. M., Blundell, S. J., Metz, T. E., Hayes, I. M., Saha, S. R., Lee, S., Woods, A. J., Movshovich, R., Thomas, S. M., Rosa, P. F. S., Butch, N. P., Paglione, J., and Sonier, J. E.

Subjects
Condensed Matter - Superconductivity
Abstract

In most superconductors electrons form Cooper pairs in a spin-singlet state mediated by either phonons or by long-range interactions such as spin fluctuations. The superconductor UTe$_2$ is a rare material wherein electrons are believed to form pairs in a unique spin-triplet state with potential topological properties. While spin-triplet pairing may be mediated by ferromagnetic or antiferromagnetic fluctuations, experimentally, the magnetic properties of UTe$_2$ are unclear. By way of muon spin rotation/relaxation ($\mu$SR) measurements on independently grown UTe$_2$ single crystals we demonstrate the existence of magnetic clusters that gradually freeze into a disordered spin frozen state at low temperatures. Our findings suggest that inhomogeneous freezing of magnetic clusters is linked to the ubiquitous residual linear term in the temperature dependence of the specific heat ($C$) and the low-temperature upturn in $C/T$ versus $T$. The omnipresent magnetic inhomogeneity has potential implications for experiments aimed at establishing the intrinsic low-temperature properties of UTe$_2$., Comment: 33 pages, 9 figures

Published
2022
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2. Muon sites in PbF2 and YF3: decohering environments and the role of anion Frenkel defects

Author

Wilkinson, J. M., Pratt, F. L., Lancaster, T., Baker, P. J., and Blundell, S. J.

Subjects
Condensed Matter - Statistical Mechanics, Condensed Matter - Materials Science
Abstract

Muons implanted into ionic fluorides often lead to a so-called F-mu-F state, in which the time evolution of the muon spin contains information about the geometry and nature of the muon site. Nuclei more distant from the muon than the two nearest-neighbor fluorine ions result in decoherence of the F-mu-F system and this can yield additional quantitative information about the state of the muon. We demonstrate how this can be applied to the determination of muon sites within the ionic fluorides alpha-PbF2 and YF3 which contain fluoride ions in different crystallographic environments. Our results can be used to distinguish between different crystal phases and reveal the presence of anion Frenkel defects in alpha-PbF2., Comment: 5 pages, 3 figures

Published
2021
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3. Information and decoherence in a muon-fluorine coupled system

Author

Wilkinson, J. M. and Blundell, S. J.

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Statistical Mechanics, Quantum Physics
Abstract

The unitary evolution of a quantum system preserves its coherence, but interactions between the system and its environment result in decoherence, a process in which the quantum information stored in the system becomes degraded. A spin-polarized positively-charged muon implanted in a fluoride crystal realises such a coherent quantum system, and the entanglement of muon and nearest-neighbour fluorine nuclear spins gives rise to an oscillatory time-dependence of the muon polarization which can be detected and measured. Here we show that the decohering effect of more distant nuclear spins can be precisely modelled, allowing a very detailed description of the decoherence processes coupling the muon-fluorine 'system' with its 'environment', and allowing us to track the system entropy as the quantum information degrades. These results show how to precisely quantify the spin relaxation of muons implanted into quantum entangled states in fluoride crystals, a feature that has hitherto only been described phenomenologically., Comment: 14 pages, 3 figures

Published
2020
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4. Electronic structure and lattice dynamics of 1T−VSe2 : Origin of the three-dimensional charge density wave

Author

Diego, Josu, primary, Subires, D., additional, Said, A. H., additional, Chaney, D. A., additional, Korshunov, A., additional, Garbarino, G., additional, Diekmann, F., additional, Mahatha, S. K., additional, Pardo, V., additional, Wilkinson, J. M., additional, Lord, J. S., additional, Strempfer, J., additional, Perez, Pablo J. Bereciartua, additional, Francoual, S., additional, Popescu, C., additional, Tallarida, M., additional, Dai, J., additional, Bianco, Raffaello, additional, Monacelli, Lorenzo, additional, Calandra, Matteo, additional, Bosak, A., additional, Mauri, Francesco, additional, Rossnagel, K., additional, Fumega, Adolfo O., additional, Errea, Ion, additional, and Blanco-Canosa, S., additional

Published
2024
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9. Accurate Fully Automatic Femur Segmentation in Pelvic Radiographs Using Regression Voting

Author

arcOGEN Consortium, Lindner, C., Thiagarajah, S., Wilkinson, J. M., Wallis, G. A., Cootes, Timothy F., Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Ayache, Nicholas, editor, Delingette, Hervé, editor, Golland, Polina, editor, and Mori, Kensaku, editor

Published
2012
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14. Entanglement between Muon and I1/2 Nuclear Spins as a Probe of Charge Environment

Author

Bonfa P., Frassineti J., Wilkinson J. M., Prando G., Isah M. M., Wang C., Spina T., Joseph B., Mitrovic V. F., De Renzi R., Blundell S. J., Sanna S., Bonfa P., Frassineti J., Wilkinson J.M., Prando G., Isah M.M., Wang C., Spina T., Joseph B., Mitrovic V.F., De Renzi R., Blundell S.J., and Sanna S.

Subjects
Dipolar interaction, Muon Spin Spectroscopy, Density Functional Theory
Abstract

We report on the first example of quantum coherence between the spins of muons and quadrupolar nuclei. We reveal that these entangled states are highly sensitive to a local charge environment and thus, can be deployed as a functional quantum sensor of that environment. The quantum coherence effect was observed in vanadium intermetallic compounds which adopt the A15 crystal structure, and whose members include all technologically pertinent superconductors. Furthermore, the extreme sensitivity of the entangled states to the local structural and electronic environments emerges through the quadrupolar interaction with the electric field gradient due to the charge distribution at the nuclear (I>1/2) sites. This case study demonstrates that positive muons can be used as a quantum sensing tool to also probe structural and charge-related phenomena in materials, even in the absence of magnetic degrees of freedom.

Published
2022

18. Physics

Author

Williams, P. C., Wilkinson, J. M., Notley, H., and Pointon, R. C. S., editor

Published
1991
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25. Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study

Author

Panoutsopoulou, K, Southam, L, Elliott, K S, Wrayner, N, Zhai, G, Beazley, C, Thorleifsson, G, Arden, N K, Carr, A, Chapman, K, Deloukas, P, Doherty, M, McCaskie, A, Ollier, W E R, Ralston, S H, Spector, T D, Valdes, A M, Wallis, G A, Wilkinson, J M, Arden, E, Battley, K, Blackburn, H, Blanco, F J, Bumpstead, S, Cupples, L A, Day-Williams, A G, Dixon, K, Doherty, S A, Esko, T, Evangelou, E, Felson, D, Gomez-Reino, J J, Gonzalez, A, Gordon, A, Gwilliam, R, Halldorsson, B V, Hauksson, V B, Hofman, A, Hunt, S E, Ioannidis, J P A, Ingvarsson, T, Jonsdottir, I, Jonsson, H, Keen, R, Kerkhof, H J M, Kloppenburg, M G, Koller, N, Lakenberg, N, Lane, N E, Lee, A T, Metspalu, A, Meulenbelt, I, Nevitt, M C, OʼNeill, F, Parimi, N, Potter, S C, Rego-Perez, I, Riancho, J A, Sherburn, K, Slagboom, P E, Stefansson, K, Styrkarsdottir, U, Sumillera, M, Swift, D, Thorsteinsdottir, U, Tsezou, A, Uitterlinden, A G, van Meurs, J B J, Watkins, B, Wheeler, M, Mitchell, S, Zhu, Y, Zmuda, J M, Zeggini, E, and Loughlin, J

Published
2011
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32. Spatial and temporal distribution of storm rainfall and its effect on hydrometric design

Author

Wilkinson, J. M.

Subjects
551.5772
Abstract

This thesis develops techniques of rainfall analysis which are based on the recognition and interpretation of spatial and temporal storm patterns. The procedures are incorporated into a method of designing a network to record storm rainfall over Northumbriao Storm rainfall distributions over the area are classified into several pattern groups and links with synoptic conditions,seasons and flood events are investigatedo Great variation is found in the storm profiles and a classification system is developed, which is related to the form of the storm hydrographo The concept of Areal Reduction Factors is discussed and a Storm-Centred Areal Reduction Factor is proposed, based on rainfall configuration and peak value o Classical statistical analysis is found to be inappropriate to the design of a network to monitor storm rainfallo Hence an empirical approach is used, based on the breakdown of storm pattern as gauge density decrea~es. Initially it was thought that techniques of Geostatistics could measure the accuracy of the networko Trend Surface Analysis and Kriging, however, are found unsuitableo Results from Semi-Variogram Analysis (previously used to assess the optimum sampling density of ore bodies) are successful, and confirm those obtained from the physical breakdown of storm pattern.

Published
1979

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