Dimensionality cross-over in magnetism: from domain walls (2D) to vortices (1D)

Dimensionality cross-over is a classical topic in physics. Surprisingly it has not been searched in micromagnetism, which deals with objects such as domain walls (2D) and vortices (1D). We predict by simulation a second-order transition between these two objects, with the wall length as the Landau parameter. This was conrmed experimentally based on micron-sized ux-closure dots

Controlled switching of N\'eel caps in flux-closure magnetic dots

While magnetic hysteresis usually considers magnetic domains, the switching of the core of magnetic vortices has recently become an active topic. We considered Bloch domain walls, which are known to display at the surface of thin films flux-closure features called N\'eel caps. We demonstrated the controlled switching of these caps under a magnetic field, occurring via the propagation of a surface vortex. For this we considered flux-closure states in elongated micron-sized dots, so that only the central domain wall can be addressed, while domains remain unaffected.Comment: 4 pages, 3 figure

Pattern languages in HCI: A critical review

This article presents a critical review of patterns and pattern languages in human-computer interaction (HCI). In recent years, patterns and pattern languages have received considerable attention in HCI for their potential as a means for developing and communicating information and knowledge to support good design. This review examines the background to patterns and pattern languages in HCI, and seeks to locate pattern languages in relation to other approaches to interaction design. The review explores four key issues: What is a pattern? What is a pattern language? How are patterns and pattern languages used? and How are values reflected in the pattern-based approach to design? Following on from the review, a future research agenda is proposed for patterns and pattern languages in HCI

Assessing the data-analysis impact of LISA orbit approximations using a GPU-accelerated response model

The analysis of gravitational wave (GW) datasets is based on the comparison of measured time series with theoretical templates of the detector's response to a variety of source parameters. For LISA, the main scientific observables will be the so-called time-delay interferometry (TDI) combinations, which suppress the otherwise overwhelming laser noise. Computing the TDI response to GW involves projecting the GW polarizations onto the LISA constellation arms, and then combining projections delayed by a multiple of the light propagation time along the arms. Both computations are difficult to perform efficiently for generic LISA orbits and GW signals. Various approximations are currently used in practice, e.g., assuming constant and equal armlengths, which yields analytical TDI expressions. In this article, we present 'fastlisaresponse', a new efficient GPU-accelerated code that implements the generic TDI response to GWs in the time domain. We use it to characterize the parameter-estimation bias incurred by analyzing loud Galactic-binary signals using the equal-armlength approximation. We conclude that equal-armlength parameter-estimation codes should be upgraded to the generic response if they are to achieve optimal accuracy for high (but reasonable) SNR sources within the actual LISA data.Comment: 15 pages, 7 figures, 2 table

The influence of laser relative intensity noise in the Laser Interferometer Space Antenna

LISA is an upcoming ESA mission that will detect gravitational waves in spaceby interferometrically measuring the separation between free-falling testmasses at picometer precision. To reach the desired performance, LISA willemploy the noise reduction technique time-delay interferometry (TDI), in whichmultiple raw interferometric readouts are time shifted and combined into thefinal scientific observables. Evaluating the performance in terms of these TDIvariables requires careful tracking of how different noise sources propagatethrough TDI, as noise correlations might affect the performance in unexpectedways. One example of such potentially correlated noise is the relativeintensity noise (RIN) of the six lasers aboard the three LISA satellites, whichwill couple into the interferometric phase measurements. In this article, wecalculate the expected RIN levels based on the current mission architecture andthe envisaged mitigation strategies. We find that strict requirements on thetechnical design reduce the effect from approximately 8.7 pm/rtHz perinter-spacecraft interferometer to that of a much lower sub-1 pm/rtHz noise,with typical characteristics of an uncorrelated readout noise after TDI. Ourinvestigations underline the importance of sufficient balanced detection of theinterferometric measurements.<br

On birational involutions of P3P^3

Let $X$ be a rationally connected three-dimensional algebraic variety and let $\tau$ be an element of order two in the group of its birational selfmaps. Suppose that there exists a non-uniruled divisorial component of the $\tau$-fixed point locus. Using the equivariant minimal model program we give a rough classification of such elements.Comment: 24 pages, late