A two band model for Superconductivity: Probing interband pair formation

We propose a two band model for superconductivity. It turns out that the simplest nontrivial case considers solely interband scattering, and both bands can be modeled as symmetric (around the Fermi level) and flat, thus each band is completely characterized by its half-band width $W_{n}$ (n=1,2). A useful dimensionless parameter is $\delta$, proportional to $W_{2}-W_{1}$. The case $\delta =0$ retrieves the conventional BCS model. We probe the specific heat, the ratio gap over critical temperature, the thermodynamic critical field and tunneling conductance as functions of $\delta$ and temperature (from zero to $T_{c}$). We compare our results with experimental results for $MgB_{2}$ and good quantitative agreement is obtained, indicating the relevance of interband coupling. Work in progress also considers the inclusion of band hybridization and general interband as well as intra-band scattering mechanisms.Comment: 7 pages, 5 figures (in postscript format). PACS numbers: 74.20.-z, 74.20.Fg, 74.70.A

Using Self-Adaptive Evolutionary Algorithms to Evolve Dynamism-Oriented Maps for a Real Time Strategy Game

9th International Conference on Large Scale Scientific Computations. The final publication is available at link.springer.comThis work presents a procedural content generation system that uses an evolutionary algorithm in order to generate interesting maps for a real-time strategy game, called Planet Wars. Interestingness is here captured by the dynamism of games (i.e., the extent to which they are action-packed). We consider two different approaches to measure the dynamism of the games resulting from these generated maps, one based on fluctuations in the resources controlled by either player and another one based on their confrontations. Both approaches rely on conducting several games on the map under scrutiny using top artificial intelligence (AI) bots for the game. Statistic gathered during these games are then transferred to a fuzzy system that determines the map's level of dynamism. We use an evolutionary algorithm featuring self-adaptation of mutation parameters and variable-length chromosomes (which means maps of different sizes) to produce increasingly dynamic maps.TIN2011-28627-C04-01, P10-TIC-608

Feshbach resonances in potassium Bose-Bose mixtures

We present a detailed study of the scattering properties of ultracold mixtures of bosonic potassium atoms. We locate 20 previously unobserved Feshbach resonances in isotopic 39K-41K mixtures. These are assigned to s-wave molecular channels by comparison to an asymptotic bound state model and coupled channels calculations. Additional Feshbach resonances are studied in spin mixtures of a single potassium isotope, both in 39K and 41K. In particular, we characterize the parameters of a selected 39K Feshbach resonance by radio-frequency association of Feshbach molecules. Our results could be exploited to refine the model potentials for potassium scattering. Furthermore, these new Feshbach resonances enlarge the range of experiments possible with degenerate Bose-Bose mixtures.Comment: 9 pages, 3 figures, 1 tabl

The Real Colegio de Cirugía de Cádiz at the origins of Banco Santander: José María Botín y Cano (c. 1794-1865)

José María Botín y Cano (c. 1794–1865) estudió (1810-1816) en el Real Colegio de Medicina y Cirugía de Cádiz, ascendió a Cirujano Primero de la Armada y fue finalmente destinado a Santander en 1827. En 1828 casó con María Petra de Aguirre y Laurencín (c. 1802-¿?), madre de Antonio López-Dóriga y Aguirre (1822-1890), promotor del “Banco de Santander”. Los hijos varones del Matrimonio Botín Aguirre, Rafael (1834- 1903) y Emilio (1835-c. 1901), serán accionistas y altos cargos de él. Por tanto, José María fue: padrastro de un fundador; ascendiente de Directivos del “Banco de Santander”; y el origen de la “Saga Botín”, que sigue vinculada al hoy “Banco Santander”.Jose María Botín y Cano (c.1794-1865) studied (1810-1816) at the Royal College of Medicine and Surgery of Cadiz, he was promoted to First Surgeon of the Navy and was assigned to the city of Santander in 1827. In 1828 he married María Petra de Aguirre y Laurencín (c. 1802-¿?), mother of Antonio López-Dóriga y Aguirre (1822-1890), who was the promoter of the “Banco de Santander”. The sons of the Botín-Aguirre couple, Rafael (1834-1903) and Emilio (1835- c.1901), were shareholders and had senior positions in the bank. Therefore, José María Botín y Cano was: the stepfather of one of the founding members, ancestor of executives of the firm and the origin of the Botín family line, which is still linked to the called "Banco Santander" today

Bright soliton to quantum droplet transition in a mixture of Bose-Einstein condensates

Attractive Bose-Einstein condensates can host two types of macroscopic self-bound states of different nature: bright solitons and quantum liquid droplets. Here, we investigate the connection between them with a Bose-Bose mixture confined in an optical waveguide. We develop a simple theoretical model to show that, depending on atom number and interaction strength, solitons and droplets can be smoothly connected or remain distinct states coexisting only in a bi-stable region. We experimentally measure their spin composition, extract their density for a broad range of parameters and map out the boundary of the region separating solitons from droplets.Comment: 9 pages, 6 figures, includes supplementary materia

Modification of as-cast Al-Mg/B4C composite by addition of Zr

Zirconium was used in Al-Mg/B4C composite to improve compocasting efficiency by increasing particle incorporation. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) results revealed that by addition of zirconium a reaction layer containing Zr, Al, B and C is formed on the interface of B4C-matrix. X-ray diffraction (XRD) analysis of extracted particles unveiled that the ZrB2 phase is the main constituent of this layer. Formation of ZrB2 is an exothermic reaction which can rise temperature locally around particles and agglomerates. Rising temperature around agglomerates in conjunction with turbulent flow of melt facilitates agglomerates wetting and dissolving into molten aluminum. As the result, final product contains more uniformly distributed B4C particles. Besides enhancing compocasting efficiency, addition of Zr and formation of reaction layer by improving particle matrix bonding quality, led to increase in ultimate tensile strength and elongation of the composite around 8% and 30%, respectively. SEM observations of the fracture surfaces confirmed that a proper bonding presents at the interface of particles and matrix in presence of Zr.Peer ReviewedPostprint (author's final draft