Complex Hybrid Inflation and Baryogenesis

We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations.Comment: 4 RevTex pages, no figures. Changes made in response to referee's comments; matches version published in Phys.Rev.Let

Triple unification of inflation, dark matter, and dark energy using a single field

We construct an explicit scenario whereby the same material driving inflation in the early Universe can comprise dark matter in the present Universe, using a simple quadratic potential. Following inflation and preheating, the density of inflaton/dark matter particles is reduced to the observed level by a period of thermal inflation, of a duration already invoked in the literature for other reasons. Within the context of the string landscape, one can further argue for a non-zero vacuum energy of this field, thus unifying inflation, dark matter and dark energy into a single fundamental field.Comment: 5 pages RevTeX with 3 figures incorporate

Inflation, dark matter and dark energy in the string landscape

We consider the conditions needed to unify the description of dark matter, dark energy and inflation in the context of the string landscape. We find that incomplete decay of the inflaton field gives the possibility that a single field is responsible for all three phenomena. By contrast, unifying dark matter and dark energy into a single field, separate from the inflaton, appears rather difficult.Comment: 4 pages RevTex4. Updated to include a toy model of reheating. Matches version accepted by Phys Rev Let

Newtonian Collapse of Scalar Field Dark Matter

In this letter, we develop a Newtonian approach to the collapse of galaxy fluctuations of scalar field dark matter under initial conditions inferred from simple assumptions. The full relativistic system, the so called Einstein-Klein-Gordon, is reduced to the Schr\"odinger-Newton one in the weak field limit. The scaling symmetries of the SN equations are exploited to track the non-linear collapse of single scalar matter fluctuations. The results can be applied to both real and complex scalar fields.Comment: 4 pages RevTex4 file, 4 eps figure

“Greener” chemical modification of cellulose nanocrystals via oxa-Michael addition with N-Benzylmaleimide

Surface modification of cellulose nanocrystals (CNCs) was conducted by an oxa-Michael addition of primary hydroxyl groups on the CNC surface with N-Benzylmaleimide (BnM). Six principles of green chemistry were used to obtain the hydrophobized CNC. Two catalytic approaches were used, a self-catalyzed reaction where alkyl sulfuric acid on the surface of the CNC was the catalyst, and a base-catalyzed approach using triethylamine (TEA). DMSO was chosen as reaction solvent due to its low cost, low toxicity and ability to disperse native CNC compared to other polar diprotic solvents. NMR and FTIR studies confirmed the successful modification of CNCs in both reaction routes. The TEA-catalyzed reaction showed a higher BnM conversion at 70 ​°C after 72 ​h (46 ​± ​2%) compared to the self-catalyzed reaction at 100 ​°C (24 ​± ​2%). Since BnM was added at a two-fold excess compared to superficial primary –OH groups, these had estimated conversions of 92% and 48%, for the base catalyzed and acid catalyzed routes, respectively. Zeta potential measurements suggest, the sulfate groups were retained after the modification reaction. AFM demonstrated no change in particle morphology after modification. Modified CNCs degraded at a higher temperature (390 ​± ​8 ​°C) when the reaction was catalyzed by TEA compared to native CNCs and the self-catalyzed product (220 ​± ​10 ​°C). Contact angle measurements demonstrated the increased hydrophobicity of the modified nanoparticles. Visual inspection and UV–vis spectroscopy demonstrated the modified CNCs had an increased affinity towards organic solvents like acetone, acetonitrile and toluene

Oscillatons formed by non linear gravity

Oscillatons are solutions of the coupled Einstein-Klein-Gordon (EKG) equations that are globally regular and asymptotically flat. By means of a Legendre transformation we are able to visualize the behaviour of the corresponding objects in non-linear gravity where the scalar field has been absorbed by means of the conformal mapping.Comment: Revtex file, 6 pages, 3 eps figure; matches version published in PR

Condiciones para una ética económica

Estas son las cuatro cuestiones que articulan la ponencia: a) Solo puede hablarse con propiedad de “ética económica” si en un discurso estrictamente científico-económico se encuentran incorporados elementos de naturaleza ética que, en cuanto tales, jueguen a la vez en ese discurso un papel estrictamente científico-económico. b) Ese es el caso, en una economía de mercado, del concepto “demanda”. Es en el juego entre la demanda y la oferta en donde se forman los precios del mercado. La demanda constituye así un elemento “científico-técnico” en la explicación del funcionamiento “técnico” del mercado. Pero a la vez, y sin confusión con la demanda en cuanto elemento técnico del mecanismo del mercado, la demanda es portadora de sustancia ética y es susceptible por tanto de ser juzgada según criterios éticos como “buena” o como “mala” a la vez que es contemplada como elemento “técnico” determinante del precio de la droga. c) Este concepto de “ética económica” es susceptible de ser articulado dentro de una “teoría de la sociedad”. d) Un claro ejemplo de esa articulación se encuentra en la obra del economista y sociólogo alemán de la Escuela de Tubinga Albert Schäffle (1831-1903) sobre la base de la teoría de la sociedad del filósofo Karl Christian Friedrich Krause (1781-1832) que tanto influyó en España. Palabras clave: ética, economía, sociología.</p