From Little Words, Big Words Grow: Annotations on the Yo, Sí Puedo Experience in Brewarrina, Australia

This article is a reflection on the application of the Cuban literacy methodology Yo, Sí Puedo to the Australian setting. The Yo, Sí Puedo / Yes, I Can! model developed in Cuba by the Instituto Pedagógico Latinoamericano y Caribeño, IPLAC (Institute of Pedagogy for Latin America and the Caribbean) has been successfully implemented across the Global South as a strategy of adult literacy. It is a legacy of our Latin American revolutionary roots, with its origin in the Freirean pedagogy of the oppressed. Expanding across continents this model continues to teach reading and writing to disenfranchised adults in marginal and Indigenous communities, from the Argentinean Chaco to Brewarrina in northern NSW, Australia. Its aim is to contribute to the hope of improving the health and educational outcomes of the country’s First Peoples. This article is indebted to conversations with the Cuban advisor of Yes, I Can!, José Manuel Chala Leblanch. Observing him working in the classroom setting of Brewarrina touched me at different levels: personally because it reminded me of my own family experiences with the education system in my country, Argentina; and professionally as an educator negotiating different languages and cultures. It also reinforced my belief in the importance of incorporating Indigenous ways of learning and teaching to Western styles of teaching and learning. I built this reflection moving from personal and poetic—visual and textual—narratives and observations to academic interventions informed by researched literature on adult and Indigenous education

Ab-initio analysis of superstructures revealed by STM on bilayer graphene

In this work we performed density functional theory calculations for a twisted bilayer graphene (BLG). Several conmensurable rotation angles were analyzed and for each one a constant height mode STM image was obtained. These STM images, calculated under the Tersoff-Hamman theory, reproduce the main features experimentally observed, paticularly superstructures and giant corrugations. In this way we confirm that STM characterization of twisted BLG can produce superstructures whose tunneling current intensity maxima occur over regions with $AA$ stacking. Additionally we give new evidence in favour of an electronic origin for the superstructures instead another physical grounds

Ladders for Wilson Loops Beyond Leading Order

We set up a general scheme to resum ladder diagrams for the quark-anti-quark potential in N=4 super-Yang-Mills theory, and do explicit calculations at the next-to-leading order. The results perfectly agree with string theory in AdS(5)xS(5) when continued to strong coupling, in spite of a potential order-of-limits problem.Comment: 18 pages, 5 figure

Breakdown of the Fermi-liquid regime in the 2D Hubbard model from a two-loop field-theoretical renormalization group approach

We analyze the particle-hole symmetric two-dimensional Hubbard model on a square lattice starting from weak-to-moderate couplings by means of the field-theoretical renormalization group (RG) approach up to two-loop order. This method is essential in order to evaluate the effect of the momentum-resolved anomalous dimension $\eta(\textbf{p})$ which arises in the normal phase of this model on the corresponding low-energy single-particle excitations. As a result, we find important indications pointing to the existence of a non-Fermi liquid (NFL) regime at temperature $T\to 0$ displaying a truncated Fermi surface (FS) for a doping range exactly in between the well-known antiferromagnetic insulating and the $d_{x^2-y^2}$-wave singlet superconducting phases. This NFL evolves as a function of doping into a correlated metal with a large FS before the $d_{x^2-y^2}$-wave pairing susceptibility finally produces the dominant instability in the low-energy limit.Comment: 9 pages, 9 figures; published in Phys. Rev.

Electronic Band Structure Effects in the Stopping of Protons in Copper

We present an ab initio study of the electronic stopping power of protons in copper over a wide range of proton velocities $v = 0.02-10~\mathrm{a.u.}$ where we take into account non-linear effects. Time-dependent density functional theory coupled with molecular dynamics is used to study electronic excitations produced by energetic protons. A plane-wave pseudopotential scheme is employed to solve the time-dependent Kohn-Sham equations for a moving ion in a periodic crystal. The electronic excitations and the band structure determine the stopping power of the material and alter the interatomic forces for both channeling and off-channeling trajectories. Our off-channeling results are in quantitative agreement with experiments, and at low velocity they unveil a crossover region of superlinear velocity dependence (with a power of $\sim 1.5$) in the velocity range $v = 0.07-0.3~\mathrm{a.u.}$, which we associate to the copper crystalline electronic band structure. The results are rationalized by simple band models connecting two separate regimes. We find that the limit of electronic stopping $v\to 0$ is not as simple as phenomenological models suggest and it plagued by band-structure effects.Comment: 8 pages, 7 figure