Lie algebra in quantum physics by means of computer algebra

This article explains how to apply the computer algebra package GAP (www.gap-system.org) in the computation of the problems in quantum physics, in which the application of Lie algebra is necessary. The article contains several exemplary computations which readers would follow in the desktop PC: such as, the brief review of elementary ideas of Lie algebra, the angular momentum in quantum mechanics, the quark eight-fold way model, and the usage of Weyl character formula (in order to construct weight modules, and to count correctly the degeneracy). This short article is a complement to the article "Computer Algebra and Material Design" [arXiv:1612.02275] by one of the authors (A.K.). The latter article is also available in the arXiv.Comment: 28 pages, 2 figures. In this version, the authors give an explanation how to construct the quantum states of baryons explicitly by means of computer algebra, without the use of Young Tableau

Deriving exact results for Ising-like models from the cluster variation method

The cluster variation method (CVM) is an approximation technique which generalizes the mean field approximation and has been widely applied in the last decades, mainly for finding accurate phase diagrams of Ising-like lattice models. Here we discuss in which cases the CVM can yield exact results, considering: (i) one-dimensional systems and strips (in which case the method reduces to the transfer matrix method), (ii) tree-like lattices and (iii) the so-called disorder points of euclidean lattice models with competitive interactions in more than one dimension.Comment: 3 pages, presented at Lattice '9

Leptogenesis in a perturbative SO(10) model

We consider a phenomenologically viable SO(10) grand unification model which allows perturbative calculations up to the Planck scale or the string scale. We use a set of Higgs superfields {10 + 16bar + 16 + 45}. In this framework, the data fitting of the charged fermion mass matrices is re-examined. This model can indeed reproduce the low-energy experimental data relating the charged fermion masses and mixings. As for the neutrino sector, we take the neutrino oscillation data as input data to construct right-handed Majorana neutrino mass matrix and get a prediction for the physics related to the right-handed neutrinos, e.g. the leptogenesis and for the proton decay. We propose two kinds of phenomenologically viable model, quoted as Model 1 and Model 2. We show that one of the models (Model 2) is consistent with all experimental constraints.Comment: 24 pages, 1 table, 8 figures; the version to appear in JHE

Making a Transnational Design History in East Asia: Yen Shuilong’s Craft-Design Movement

Yen Shuilong (1903-97) was born in Taiwan within the ‘Japanese Empire’ but his live is dominated by what we would now call transnational activities. During the fifteen years since his death, there have been a number of retrospective exhibitions on him, and these have served to anchor his status in Taiwanese history of art and design. From last year through to this year the Taipei Fine Arts Museum organised an exhibition ‘The Public Spirit, Beauty in the Making： Shui-Long Yen’. (Fig. 2) On the other hand in Japan, even though Yen was Japanese until 1945, he hasn’t been well recognized, and it appears as though he may have been intentionally forgotten with the history of Japanese colonization

Motivation and demotivation over two years: A case study of English language learners in Japan

This paper is about four Japanese university students majoring in international studies, who participated in a two-year study examining changes in their motivation. Using monthly interviews and a 29-item questionnaire on Dörnyei’s (2005) L2 motivational self system that was administered alongside each interview, the trajectories of learner motivation were investigated, based on both quantitative and qualitative data. First, changes in the participants’ motivation were identified using quantitative data. Next, a variety of motivators and demotivators that learners experienced both inside and outside of their classrooms were analyzed using the qualitative data. With the data obtained, this study focuses on how four learners’ language learning motivation and contexts adapt to each other, and how the dynamics of the four learners’ motivation changes due to their learning experiences. Each learner was different in their trajectory of motivation and the kinds of motivators and demotivators that they experienced in their particular contexts. The four learners underwent unique motivators and demotivators, and reacted differently. While participants identified their ideal L2 selves, or ought-to L2 selves, these self-guides were not strengthened by their L2 experiences over time. Based on these findings, the importance of studying the rich experiences of language learners in motivation research is discussed

Symmetries in the third Painlev\'e equation arising from the modified Pohlmeyer-Lund-Regge hierarchy

We propose a modification of the AKNS hierarchy that includes the "modified" Pohlmeyer-Lund-Regge (mPLR) equation. Similarity reductions of this hierarchy give the second, third, and fourth Painlev\'e equations. Especially, we present a new Lax representation and a complete description of the symmetry of the third Painlev\'e equation through the similarity reduction. We also show the relation between the tau-function of the mPLR hierarchy and Painlev\'e equations.Comment: 23 page