Facilitated spin models: recent and new results

Facilitated or kinetically constrained spin models (KCSM) are a class of interacting particle systems reversible w.r.t. to a simple product measure. Each dynamical variable (spin) is re-sampled from its equilibrium distribution only if the surrounding configuration fulfills a simple local constraint which \emph{does not involve} the chosen variable itself. Such simple models are quite popular in the glass community since they display some of the peculiar features of glassy dynamics, in particular they can undergo a dynamical arrest reminiscent of the liquid/glass transitiom. Due to the fact that the jumps rates of the Markov process can be zero, the whole analysis of the long time behavior becomes quite delicate and, until recently, KCSM have escaped a rigorous analysis with the notable exception of the East model. In these notes we will mainly review several recent mathematical results which, besides being applicable to a wide class of KCSM, have contributed to settle some debated questions arising in numerical simulations made by physicists. We will also provide some interesting new extensions. In particular we will show how to deal with interacting models reversible w.r.t. to a high temperature Gibbs measure and we will provide a detailed analysis of the so called one spin facilitated model on a general connected graph.Comment: 30 pages, 3 figure

Jamming percolation and glassy dynamics

We present a detailed physical analysis of the dynamical glass-jamming transition which occurs for the so called Knight models recently introduced and analyzed in a joint work with D.S.Fisher \cite{letterTBF}. Furthermore, we review some of our previous works on Kinetically Constrained Models. The Knights models correspond to a new class of kinetically constrained models which provide the first example of finite dimensional models with an ideal glass-jamming transition. This is due to the underlying percolation transition of particles which are mutually blocked by the constraints. This jamming percolation has unconventional features: it is discontinuous (i.e. the percolating cluster is compact at the transition) and the typical size of the clusters diverges faster than any power law when $\rho\nearrow\rho_c$. These properties give rise for Knight models to an ergodicity breaking transition at $\rho_c$: at and above $\rho_{c}$ a finite fraction of the system is frozen. In turn, this finite jump in the density of frozen sites leads to a two step relaxation for dynamic correlations in the unjammed phase, analogous to that of glass forming liquids. Also, due to the faster than power law divergence of the dynamical correlation length, relaxation times diverge in a way similar to the Vogel-Fulcher law.Comment: Submitted to the special issue of Journal of Statistical Physics on Spin glasses and related topic

Children and young people's experiences of living with developmental coordination disorder/dyspraxia: study protocol for a qualitative evidence synthesis

Children with developmental coordination disorder (DCD) face significant challenges to deal with everyday activities due to underlying motor proficiency difficulties. These challenges affect children and young people’s participation; that is, involvement in daily life situations. In the past, limited consideration was given to personal experience of events, relationships and everyday life in children and young people with DCD; as a result, understanding what it is like to live with DCD is not well conceptualised in the literature. There is a pressing need to synthesise the findings of discrete qualitative studies to advance the conceptual understanding of living with DCD, to inform health service delivery and the development and implementation of complex interventions. This study aims to systematically review and synthesise qualitative literature regarding children and young people’s experiences and views of everyday life and living with DCD. The method of qualitative evidence synthesis that will be followed in this review is a meta-ethnography. The eMERGe and PRISMA reporting guidelines will be used in the development, design and reporting of this review. Nine databases will be searched; Academic Search Complete, AMED, CINAHL, MEDLINE, PsychArticles, PsychInfo, EMBASE, SPORTDiscus, and Web of Science. Two independent reviewers will use the Joanna Briggs Institute Checklist to appraise all included papers. The findings of this meta-ethnography will endeavour to inform future research, policy and practice. In particular, the results will help to inform the design of future complex interventions to meet the needs of children and young people with DCD. Dissemination will involve the publication of the results in a peer-reviewed journal. Increasingly researchers and policymakers are calling for services to be informed by the perspective and voice of children with DCD; therefore, a policy brief will be published so that the findings are widely available