scholarly journals Hadronic effects in leptonic systems: muonium hyperfine structure and anomalous magnetic moment of muon

2002 ◽  
Vol 80 (11) ◽  
pp. 1297-1303 ◽  
Author(s):  
S I Eidelman ◽  
S G Karshenboim ◽  
V A Shelyuto
Keyword(s):  
Hyperfine Structure ◽  
Magnetic Moment ◽  
Ground State ◽  
Anomalous Magnetic Moment ◽  
Higher Order ◽  
Order Effects ◽  
Hadronic Contribution ◽  
Muonium Hyperfine ◽  
Higher Order Effects

The contributions of hadronic effects to muonium physics and the anomalous magnetic moment of muon are considered. Special attention is paid to higher order effects and the uncertainty related to the hadronic contribution to the hyperfine-structure interval in the ground state of muonium. PACS Nos.: 12.20-m, 36.10Dr, 31.30Jv, 13.65+i

scholarly journals Frustrated order by disorder: The pyrochlore anti-ferromagnet with bond disorder

2001 ◽  
Vol 79 (11-12) ◽  
pp. 1365-1371 ◽  
Author(s):  
L Bellier-Castella ◽  
M JP Gingras ◽  
P CW Holdsworth ◽  
R Moessner
Keyword(s):  
Ground State ◽  
Energy Landscape ◽  
Matter Mater ◽  
Higher Order ◽  
The Other ◽  
Order Effects ◽  
Weak Bond ◽  
Ground State Degeneracy ◽  
Higher Order Effects ◽  
Substantial Degree

The classical Heisenberg anti-ferromagnet on the pyrochlore lattice is macroscopically and continuously degenerate and the system remains disordered at all temperatures, even in the presence of weak dilution with nonmagnetic ions. We show that, in contrast, weak-bond disorder lifts the ground-state degeneracy in favour of locally collinear spin configurations. We present a proof that for a single tetrahedron the ground state is perfectly collinear but identify two mechanisms that preclude the establishment of a globally collinear state; one due to frustration and the other due to higher order effects. We thus obtain a rugged energy landscape, which is necessary to account for the glassy phenomena found in real systems such as the pyrochlore Y2Mo2O7 recently reported by Booth et al. (Phys. Rev. B: Condens. Matter Mater. Phys. 62, R755 (2000).) to contain a substantial degree of bond disorder. PACS Nos.: 75.10.Hk, 75.40.Mg, 75.40.Gb

Time after time: support for memory accounts of temporal preparation.

2019 ◽  
Author(s):  
Joe Butler ◽  
Samuel Ngabo ◽  
Marcus Missal
Keyword(s):  
Response Times ◽  
Reaction Times ◽  
Evidence Base ◽  
Higher Order ◽  
Order Effects ◽  
Previous Trial ◽  
Adaptive Responses ◽  
Temporal Preparation ◽  
Subsequent Trial ◽  
Higher Order Effects

Complex biological systems build up temporal expectations to facilitate adaptive responses to environmental events, in order to minimise costs associated with incorrect responses, and maximise the benefits of correct responses. In the lab, this is clearly demonstrated in tasks which show faster response times when the period between warning (S1) and target stimulus (S2) on the previous trial was short and slower when the previous trial foreperiod was long. The mechanisms driving such higher order effects in temporal preparation paradigms are still under debate, with key theories proposing that either i) the foreperiod leads to automatic modulation of the arousal system which influences responses on the subsequent trial, or ii) that exposure to a foreperiod results in the creation of a memory trace which is used to guide responses on the subsequent trial. Here we provide data which extends the evidence base for the memory accounts, by showing that previous foreperiod exposures are cumulative with reaction times shortening after repeated exposures; whilst also demonstrate that the higher order effects associated with a foreperiod remain active for several trials.

scholarly journals Responsible innovation, anticipation and responsiveness: case studies of algorithms in decision support in justice and security, and an exploration of potential, unintended, undesirable, higher-order effects

AI and Ethics ◽  
2021 ◽  
Author(s):  
Marc Steen ◽  
Tjerk Timan ◽  
Ibo van de Poel
Keyword(s):  
Decision Support ◽  
Case Studies ◽  
Personal Data ◽  
Higher Order ◽  
Popular Media ◽  
Responsible Innovation ◽  
Order Effects ◽  
Key Dimensions ◽  
Higher Order Effects

AbstractThe collection and use of personal data on citizens in the design and deployment of algorithms in the domain of justice and security is a sensitive topic. Values like fairness, autonomy, privacy, accuracy, transparency and property are at stake. Negative examples of algorithms that propagate or exacerbate biases, inequalities or injustices have received ample attention, both in academia and in popular media. To supplement this view, we will discuss two positive examples of Responsible Innovation (RI): the design and deployment of algorithms in decision support, with good intentions and careful approaches. We then explore potential, unintended, undesirable, higher-order effects of algorithms—effects that may occur despite good intentions and careful approaches. We do that by engaging with anticipation and responsiveness, two key dimensions of Responsible Innovation. We close the paper with proposing a framework and a series of tentative recommendations to promote anticipation and responsiveness in the design and deployment of algorithms in decision support in the domain of justice and security.

scholarly journals Stochastic computation of g − 2 in QED

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ryuichiro Kitano ◽  
Hiromasa Takaura ◽  
Shoji Hashimoto
Keyword(s):  
Perturbation Theory ◽  
Numerical Computation ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Stochastic Perturbation ◽  
Higher Order ◽  
Feynman Diagrams ◽  
Perturbative Series ◽  
Physical Quantities

Abstract We perform a numerical computation of the anomalous magnetic moment (g − 2) of the electron in QED by using the stochastic perturbation theory. Formulating QED on the lattice, we develop a method to calculate the coefficients of the perturbative series of g − 2 without the use of the Feynman diagrams. We demonstrate the feasibility of the method by performing a computation up to the α3 order and compare with the known results. This program provides us with a totally independent check of the results obtained by the Feynman diagrams and will be useful for the estimations of not-yet-calculated higher order values. This work provides an example of the application of the numerical stochastic perturbation theory to physical quantities, for which the external states have to be taken on-shell.

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