From the fuzzy disc to edge currents in Chern-Simons Theory

We present a brief review of the fuzzy disc, the finite algebra approximating functions on a disc, which we have introduced earlier. We also present a comparison with recent papers of Balachandran, Gupta and K\"urk\c{c}\"{u}o\v{g}lu, and of Pinzul and Stern, aimed at the discussion of edge states of a Chern-Simons theory.Comment: 8 pages, 6 figures, Talk presented at ``Space-time and Fundamental Interactions: Quantum Aspects'', conference in honour of A. P. Balachandran's 65th birthday. References added and one misprint correcte

Topology and quantum states: The electron-monopole system

This paper starts by describing the dynamics of the electronmonopole system at both classical and quantum level by a suitable reduction procedure. This suggests, in order to realise the space of states for quantum systems which are classically described on topologically non-trivial configuration spaces, to consider Hilbert spaces of exterior differential forms. Among the advantages of this formulation, we present—in the case of the group SU(2), how it is possible to obtain all unitary irreducible representations on such a Hilbert space, and how it is possible to write scalar Dirac-type operators, following an idea by K¨ahler

Geometry of the Gauge Algebra in Noncommutative Yang-Mills Theory

A detailed description of the infinite-dimensional Lie algebra of star-gauge transformations in noncommutative Yang-Mills theory is presented. Various descriptions of this algebra are given in terms of inner automorphisms of the underlying deformed algebra of functions on spacetime, of deformed symplectic diffeomorphisms, of the infinite unitary Lie algebra, and of the algebra of compact operators on a quantum mechanical Hilbert space. The spacetime and string interpretations are also elucidated.Comment: 49 pages LaTeX; v2: References added; v3: Typos corrected and references added; final version published in JHE

The beat of a fuzzy drum: fuzzy Bessel functions for the disc

The fuzzy disc is a matrix approximation of the functions on a disc which preserves rotational symmetry. In this paper we introduce a basis for the algebra of functions on the fuzzy disc in terms of the eigenfunctions of a properly defined fuzzy Laplacian. In the commutative limit they tend to the eigenfunctions of the ordinary Laplacian on the disc, i.e. Bessel functions of the first kind, thus deserving the name of fuzzy Bessel functions.Comment: 30 pages, 8 figure

Turning gender inside out: delivering higher education in women’s carceral spaces

This article is a critical reflection of the role of gender in the delivery of a higher education course based on the Inside-Out Prison Exchange Programme. Related concepts such as hegemonic masculinity, heteronormativity, and intersectionality are discussed within the prison education setting. This reflection primarily draws on critical incidents from the experiences of the first three authors facilitating a higher education course in a women’s prison in England. One major reflection is that learning in a group of ‘inside’ and ‘outside’ students, all self-identified women, who vary along the dimensions of age, class, ethnicity, nationality and sexual expression, presented unique dynamics. This included working with both collectiveness and difference, gender-aligned expectations about behaviour, and experiences of control, criminal justice and higher education. Additionally, all four authors' experiences of delivering various higher education courses under different prison-education partnership models in both men and women’s prisons allows for comparison and reflection on the institutional reproduction of gender norms. These reflections point to the conclusion that, despite the strong presence of intersectional divisions, gender can become a uniting force when working with an all-women student group, fostering critical thinking and engagement with challenging structural issues. However further reflection considers that being gender-conscious in the classroom should not be limited to all-women student cohorts, as this is exactly what may enable facilitators to tackle some of the issues produced by hegemonic masculinity in a mixed prison classroom

Causality in Schwinger's Picture of Quantum Mechanics

This paper begins the study of the relation between causality and quantum mechanics, taking advantage of the groupoidal description of quantum mechanical systems inspired by Schwinger’s picture of quantum mechanics. After identifying causal structures on groupoids with a particular class of subcategories, called causal categories accordingly, it will be shown that causal structures can be recovered from a particular class of non-selfadjoint class of algebras, known as triangular operator algebras, contained in the von Neumann algebra of the groupoid of the quantum system. As a consequence of this, Sorkin’s incidence theorem will be proved and some illustrative examples will be discussed.This researchwas funded by the Spanish Ministry of Economy and Competitiveness (MINECO), through the Severo Ochoa Programme for Centres of Excellence in RD (SEV-2015/0554), the MINECO research project PID2020-117477GB-I00, the Comunidad de Madrid project QUITEMAD+, S2013/ICE- 2801, the CONEX-Plus programme (University Carlos III of Madrid), Marie Sklodowska-Curie COFUND Action (H2020-MSCA-COFUND-2017-GA 801538). This work has been supported by the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual Agreement with UC3M in the line of “Research Funds for Beatriz Galindo Fellowships” (C&QIG-BG-CM-UC3M), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation)

CreaSenses: fostering creativity through olfactory cues

Smell is a strong trigger of memories and creativity. Different smells can create sensitive environments that can foster creative tasks. In this paper, we present CreaSenses, a study that includes olfactory cues, representing different types of sensitive environ ments such as “food” and “ambience” in a within-subject design. Our aim was to obtain a deeper understanding of which smell cues promote higher levels of creativity during the process of creative writing. We discuss the results in the light of creative senses and potential implications for the design of creativity support tools. In addition, our study was evaluated trough the Creativity Support Index.info:eu-repo/semantics/publishedVersio

Flotation Sludges from Precious Metal Recovery Processes: From Waste to Secondary Raw Material in Ceramics

In this study, we investigated flotation muds (FM) deriving from the recovery processes of precious metals contained in e-waste (wastes from electronics) and exhausted catalysts. FM consist of an amorphous phase, corresponding to a Ca- and Al-rich silicatic glass, potentially usable as a secondary raw material (SRM) to obtain a final ceramic product (CFM). A high FM amount was used in our ceramic tests, and suitably mixed with variable percentages of other phases. Chemical analysis, phase composition, microstructure, pore pattern and technological properties of the new ceramic products were determined using different analytical techniques, including bulk XRF, XRD, SEM-EDS and µCT. The CFM product predominantly consists of nepheline, pyroxene and wollastonite as the main crystalline phases, with a minor amorphous phase occurring as a compact interstitial matrix. The ceramic product has a porous interconnected microstructure. Nevertheless, this microstructure does not negatively affect the mechanical properties of the ceramic product, as testified by the geo-mechanical tests, revealing good properties in terms of bending and uniaxial strength. These preliminary results point out that FM recycling is feasible, at least at the laboratory scale

Toward Performance-Portable PETSc for GPU-based Exascale Systems

The Portable Extensible Toolkit for Scientific computation (PETSc) library delivers scalable solvers for nonlinear time-dependent differential and algebraic equations and for numerical optimization.The PETSc design for performance portability addresses fundamental GPU accelerator challenges and stresses flexibility and extensibility by separating the programming model used by the application from that used by the library, and it enables application developers to use their preferred programming model, such as Kokkos, RAJA, SYCL, HIP, CUDA, or OpenCL, on upcoming exascale systems. A blueprint for using GPUs from PETSc-based codes is provided, and case studies emphasize the flexibility and high performance achieved on current GPU-based systems.Comment: 15 pages, 10 figures, 2 table