Ferromagnetic 0-pi Junctions as Classical Spins

The ground state of highly damped PdNi based 0-pi ferromagnetic Josephson junctions shows a spontaneous half quantum vortex, sustained by a supercurrent of undetermined sign. This supercurrent flows in the electrode of a Josephson junction used as a detector and produces a phi(0)/4 shift in its magnetic diffraction pattern. We have measured the statistics of the positive or negative sign shift occurring at the superconducting transition of such a junction. The randomness of the shift sign, the reproducibility of its magnitude and the possibility of achieving exact flux compensation upon field cooling: all these features show that 0-pi junctions behave as classical spins, just as magnetic nanoparticles with uniaxial anisotropy.Comment: 4 pages, 4 figure

Photon mediated interaction between distant quantum dot circuits

Engineering the interaction between light and matter is an important goal in the emerging field of quantum opto-electronics. Thanks to the use of cavity quantum electrodynamics architectures, one can envision a fully hybrid multiplexing of quantum conductors. Here, we use such an architecture to couple two quantum dot circuits . Our quantum dots are separated by 200 times their own size, with no direct tunnel and electrostatic couplings between them. We demonstrate their interaction, mediated by the cavity photons. This could be used to scale up quantum bit architectures based on quantum dot circuits or simulate on-chip phonon-mediated interactions between strongly correlated electrons

Shot noise in carbon nanotube based Fabry-Perot interferometers

We report on shot noise measurements in carbon nanotube based Fabry-Perot electronic interferometers. As a consequence of quantum interferences, the noise power spectral density oscillates as a function of the voltage applied to the gate electrode. The quantum shot noise theory accounts for the data quantitatively. It allows to confirm the existence of two nearly degenerate orbitals. At resonance, the transmission of the nanotube approaches unity, and the nanotube becomes noiseless, as observed in quantum point contacts. In this weak backscattering regime, the dependence of the noise on the backscattering current is found weaker than expected, pointing either to electron-electron interactions or to weak decoherence

Dementia Discourse: From Imposed Suffering to Knowing Other-Wise

This work, first published in Journal of Applied Hermeneutics is made available here under the Creative Commons Attribution 3.0 Unported license. https://creativecommons.org/licenses/by/3.0/. Original article available at: http://hdl.handle.net/10515/sy5222rn5The authors revisit the troubling discourse surrounding the diagnosis of dementia. A critique of the predominant words and images in health care literature, public discourse, and policy is considered from multiple angles. The authors link the dominant words and images with a form of inter-relational violence. Contrary images grounded in research and experience offer a different view of what it is like to live with a diagnosis of dementia—a view that is life-affirming and based in relationality and possibility. Concepts of embodied selfhood and knowing other-wise are portrayed as doorways to transforming a discourse of violence toward a discourse of compassion and ethical relating

Investigation of validity, reliability, and practice effects of the Immediate Postconcussion Assessment and Cognitive Test (ImPACT) and traditional paper-pencil neuropsychological tests

The purpose of this study was to determine: 1) if an athlete’s age significantly affects neuropsychological test performance, 2) if an athlete’s performance remains consistent across serial neuropsychological tests, and 3) the concurrent validity of the Immediate Postconcussion and Cognitive Test (ImPACT) scores when compared to traditional paper-pencil test scores of similar cognitive domains. A healthy sample of 20 college and 20 high school athletes completed both ImPACT and traditional paper-pencil neuropsychological test batteries on three separate occasions. Means and standard deviations, 2x3 mixed model ANOVAs (age x session), reliability (ICC2,1) and precision (SEM) values, and linear regressions were calculated on outcome measures for both test batteries. The ANOVAs revealed significant main effects of age for the Trail Making Test Form B (TMT-B) total time and ImPACT processing speed composite score with college athletes performing better than high school students on both measures. The ANOVAs also revealed significant main effects of session for the Brief Visuospatial Memory Test – Revised (BVMT-R) total recalled (immediate and delayed), the TMT-B total time, Stroop Test total score, and ImPACT processing speed composite score. Reliability measures ranged from 0.12 to 0.72 with the majority of the outcome measures achieving a moderate level of reliability across testing iii sessions. Linear regressions revealed that ImPACT test scores had low levels of shared variance with select paper-pencil neuropsychological tests. Coefficients of determination for these linear regressions left much of the variance unexplained (52-88%). Only the ImPACT Three Letters average counted correctly reached a moderate level (R2=0.481). This study demonstrates the need of the clinician to understand the differences in neuropsychological test performance for athletes of different age groups and across serial neuropsychological tests. It is also recommended that caution be exhibited when evaluating ImPACT test results of athletes 15-17 and 19-21 as the concurrent validity has not been conclusively proven

Theoretical description of the ferromagnetic π\pi -junctions near the critical temperature

The theory of ferromagnetic Pi-junction near the critical temperature is presented. It is demonstrated that in the dirty limit the modified Usadel equation adequately describes the proximity effect in ferromagnets. To provide the description of an experimentally relevant situation, oscillations of the Josephson critical current are calculated as a function of ferromagnetic layer thickness for different transparencies of the superconductor-ferromagnet interfaces.Comment: 12 pages, 4 figures, submitted to Phys. Rev.

Mesoscopic effects in superconductor-ferromagnet-superconductor junctions

We show that at zero temperature the supercurrent through the superconductor - ferromagnetic metal - superconductor junctions does not decay exponentially with the thickness $L$ of the junction. At large $L$ it has a random sample-specific sign which can change with a change in temperature. In the case of mesoscopic junctions the phase of the order parameter in the ground state is a random sample-specific quantity. In the case of junctions of large area the ground state phase difference is $\pm \pi/2$.Comment: 4 pages, 1 figur

Knowledge as Embodied, Imaginative and Foolish Enactment: Exploring Dementia Experiences through Theater

In this article, we provide an example of a performance-research project to advance understandings of the ways artistic and scientific processes work in conversation. Drawing on the research-informed play Cracked: New Light on Dementia, we consider the interrelationship among cultural narratives (including the perpetuation of oppressive narratives of marginalized people), aesthetic and artistic exploration (sensory and emotional exploration together with dramaturgy and theatricality), and social critique for the purposes of broader social change. By explicating three interrelated "acts" of our process, including preparation, execution and exhibition (THOMPSON, 2015), we share the ways artistic practices were flexibly used to generate new cultural knowledge about the ways we think, feel, and sense about dementia to mobilize social good. With our work we criticize institutional and research structures that deny arts processes the status of "research," as well as challenge traditional modes of knowledge and knowledge production.In diesem Beitrag berichten wir über ein Beispiel performativer Forschung mit dem Ziel, künstlerische und wissenschaftliche Prozesse besser zu verstehen. Ausgehend von dem Theaterstück "Cracked: New Light on Dementia" beleuchten wir die Beziehung zwischen kulturellen Narrativen (inkl. der Verfestigung unterdrückerischer Narrative über marginalisierte Menschen), ästhetischer und künstlerischer Forschung (sensorisches und emotionales Involvement sowie Dramaturgie und Theatralität) und sozialer Kritik mit dem Ziel breiterer sozialer Veränderungen. An drei miteinander verknüpften "Akten" unseres Forschungsprozesses - Vorbereitung, Ausführung und Ausstellung (THOMPSON 2015) - veranschaulichen wir, wie künstlerische Praktiken flexibel genutzt wurden, um neues kulturelles Wissen darüber zu erzeugen, wie wir Demenz denken, erleben und wahrnehmen, und so ein soziales Gut zu initiieren. Mit unserer Arbeit kritisieren wir institutionelle und wissenschaftliche Strukturen, die Kunst den Status von Forschung absprechen, und wir fordern traditionelle Weisen von Wissen und Wissensproduktion heraus

Rashba spin-orbit coupling and spin precession in carbon nanotubes

The Rashba spin-orbit coupling in carbon nanotubes and its effect on spin-dependent transport properties are analyzed theoretically. We focus on clean non-interacting nanotubes with tunable number of subbands $N$. The peculiar band structure is shown to allow in principle for Datta-Das oscillatory behavior in the tunneling magnetoresistance as a function of gate voltage, despite the presence of multiple bands. We discuss the conditions for observing Datta-Das oscillations in carbon nanotubes.Comment: 12 pages, published versio