Scattering of instantons, monopoles and vortices in higher dimensions

We consider Yang-Mills theory on manifolds ${\mathbb R}\times X$ with a $d$-dimensional Riemannian manifold $X$ of special holonomy admitting gauge instanton equations. Instantons are considered as particle-like solutions in $d+1$ dimensions whose static configurations are concentrated on $X$. We study how they evolve in time when considered as solutions of the Yang-Millsequations on ${\mathbb R}\times X$ with moduli depending on time $t\in{\mathbb R}$. It is shown that in the adiabatic limit, when the metric in the $X$ direction is scaled down, the classical dynamics of slowly moving instantons corresponds to a geodesic motion in the moduli space $\cal M$ of gauge instantons on $X$. Similar results about geodesic motion in the moduli space of monopoles and vortices in higher dimensions are briefly discussed.Comment: 10 pages; v2: 2 refs. added, published version; v3: typos correcte

On Infinite-Dimensional Algebras of Symmetries of the Self-Dual Yang-Mills Equations

Infinite-dimensional algebras of hidden symmetries of the self-dual Yang-Mills equations are considered. A current-type algebra of symmetries and an affine extension of conformal symmetries introduced recently are discussed using the twistor picture. It is shown that the extended conformal symmetries of the self-dual Yang-Mills equations have a simple description in terms of Ward's twistor construction.Comment: 10 pages, LaTeX, final version (to appear in J.Math.Phys.

Financing schemes for residential, grid-connected PV solar systems in BCS, Mexico

This article presents two proposals to spur the extensive adoption of grid-connected, residential, solar photovoltaic systems in the Mexican state of Baja California Sur. To this aim, electricity generation costs and subsidies were estimated first, together with time-of-generation avoided costs that could result from the implementation of such solar systems. An overview of financing mechanisms for solar and other renewable energies around the world is also presented followed by current mechanisms available in Mexico. The first proposal is centered around the operation of a solar energy service company that would receive the avoided cost of generation as compensation in return for sourcing, installing, and maintaining solar PV systems on residential users’ roofs. This would free up the residential user from any future electricity payments. The second proposal consists in the implementation of a feed-in tariff (FiT), currently unavailable in Mexico for residential users. The FiT could be funded from the avoided generation cost in conventional plants plus the corresponding savings from self-generation of electricity. Alternatively, the option of funding the FiT from small increases in electricity prices to all customers was also explored. Present value analyses suggest that both proposals are worthwhile pursuing in Baja California Sur

Self-assembled metallic nanoparticle template --- a new approach of surface nanostructuring at nanometer scale

In the present work, the formation of silver and copper nanostructures on highly oriented pyrolytic graphite (HOPG) modified with self-assembled gold nanoparticles (Au NPs) is demonstrated. Surface patterning with nanometer resolution was achieved. Different methods such as field emission scanning electron microscopy (FEGSEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) were used to illustrate a selective deposition of silver and copper on Au NPs. The mechanism of silver and copper ions reduction on Au NP with $n$-dodecanethiol coating is discussed.Comment: 6 pages, 3 figure