‘Plumb line scribe’: using multimedia to preserve traditional craft skills

The skills required in craft practice involve a high degree of tacit knowledge which is frequently difficult for the craft expert to articulate. N. Wood, a multimedia designer, has undertaken extensive research over the last ten years seeking to understand the knowledge of skilled craftsmen and find methods of capturing and passing it on. She has developed an elicitation strategy that employs an expert learner to uncover the skilled knowledge of master craftsmen, and a transmission strategy based on the concept of bridges to assist the design of learning resources for novices. U. H. Lassen has used the techniques developed by Wood to record and transmit the skilled knowledge needed to make timber-framed buildings, knowledge that today is in danger of being lost. The focus of the study has been the procedure for scribing timbers, which is a central part of the building process. The aim of the research was to investigate the possibility of combining the two roles defined in Wood’s research as an expert learner and designer. Being a skilled carpenter, Lassen has acted as an expert learner, learning the skills of scribing through a combination of researching existing documentation, working with master craftsmen and his own experimentation. At the same time, he developed and tested a multimedia learning resource to provide ‘bridges’ for new learners to this knowledge. The outcome of the application of Wood’s elicitation and transmission strategy to plumb line scribing is a demonstration of the transferability of Wood’s methods within this new context. This is important because it reveals the potential for other craft practitioners to apply Wood’s methods to their own learning and teaching, and produce learning resources to provide bridges to their craft knowledge and preserve their unique skills

Continuous Variable Entanglement and Squeezing of Orbital Angular Momentum States

We report the first experimental characterization of the first-order continuous variable orbital angular momentum states. Using a spatially non-degenerate optical parametric oscillator (OPO) we produce quadrature entanglement between the two first-order Laguerre-Gauss modes. The family of OAM modes is mapped on an orbital Poincare sphere, and the modes position on the sphere is spanned by the three orbital parameters. Using the non-degenerate OPO we produce squeezing of these parameters, and as an illustration, we reconstruct the "cigar-shaped" uncertainty volume on the orbital Poincare sphere.Comment: 4 pages, 4 figure

Generation of Polarization Squeezing with Periodically Poled KTP at 1064 nm

We report the experimental demonstration of directly produced polarization squeezing at 1064 nm from a type I optical parametric amplifier (OPA) based on a periodically poled KTP crystal (PPKTP). The orthogonal polarization modes of the polarization squeezed state are both defined by the OPA cavity mode, and the birefringence induced by the PPKTP crystal is compensated for by a second, but inactive, PPKTP crystal. Stokes parameter squeezing of 3.6 dB and anti squeezing of 9.4 dB is observed.Comment: 4 pages, 2 figure

Experimental Investigation of the Evolution of Gaussian Quantum Discord in an Open System

Gaussian quantum discord is a measure of quantum correlations in Gaussian systems. Using Gaussian discord we quantify the quantum correlations of a bipartite entangled state and a separable two-mode mixture of coherent states. We experimentally analyze the effect of noise addition and dissipation on Gaussian discord and show that the former noise degrades the discord while the latter noise for some states leads to an increase of the discord. In particular, we experimentally demonstrate the near-death of discord by noisy evolution and its revival through dissipation.Comment: 5 pages, 5 figure