Self-gravitating system made of axions

We show that the inclusion of an axion-like effective potential in the construction of a self-gravitating system made of scalar fields leads to a decrease on its compactness when the value of the self-interaction coupling constant is increased. By including the current values for the axion mass m and decay constant f_a, we have computed the mass and the radius for self-gravitating systems made of axion particles. It is found that such objects will have asteroid-size masses and radius of few meters, then, the self-gravitating system made of axions could play the role of scalar mini-machos that are mimicking a cold dark matter model for the galactic halo.Comment: 5 pages, 3 figures. References added. Accepted for publication in Physical Review

Probing nonstandard interactions with reactor neutrinos

New limits on the weak mixing angle and on the electron neutrino effective charge radius in the low energy regime, below 100 MeV, are obtained from a combined fit of all electron-(anti)neutrino electron elastic scattering measurements. We have included the recent TEXONO measurement with a CsI (Tl) detector. Only statistical error of this measurement has been taken into account. Weak mixing angle is found to be sin^2 theta_W = 0.255 +0.022 -0.023. The electron neutrino effective charge radius squared is bounded to be r^2 = (0.9 +0.9 -1.0) x 10^{-32} cm^2. The sensitivity of future low energy neutrino experiments to nonstandard interactions of neutrinos with quarks is also discussed.Comment: 3 pages, 2 figures, talk given at the Neutrino Oscillation Workshop (NOW 2008), Otranto, Italy, September 6-13, 2008. Misprints correcte

Constraining scalar field properties with boson stars as black hole mimickers

Constraints to the mass of a scalar field and the strength of its self-interacting coupling constant are obtained. This was done using observations of stellar dynamics at the center of our galaxy and by assuming that the dark compact object responsible of such dynamics is a boson star and not a supermassive black hole. We show that if such scalar field represents a spin-zero particle with cross section high enough to be considered collisional dark matter, there is a region of parameters compatible with both conditions: that the scalar field play the role of collisional dark matter and that it can form objects with the mass and compactness compatible with stellar kinematics.Comment: To appear in the Procceedings of the VIII Workshop of the Gravitation and Mathematical Physics Division of the Mexican Physical Societ

Universal Mass Texture, CP violation and Quark-Lepton Complementarity

The measurements of the neutrino and quark mixing angles satisfy the empirical relations called Quark-Lepton Complementarity. These empirical relations suggest the existence of a correlation between the mixing matrices of leptons and quarks. In this work, we examine the possibility that this correlation between the mixing angles of quarks and leptons originates in the similar hierarchy of quarks and charged lepton masses and the seesaw mechanism type~I, that gives mass to the Majorana neutrinos. We assume that the similar mass hierarchies of charged lepton and quark masses allows us to represent all the mass matrices of Dirac fermions in terms of a universal form with four texture zeroes.Comment: 14 page

Transfer of coherence from atoms to mixed field states in a two-photon lossless micromaser

We propose a two-photon micromaser-based scheme for the generation of a nonclassical state from a mixed state. We conclude that a faster, as well as a higher degree of field purity is achieved in comparison to one-photon processes. We investigate the statistical properties of the resulting field states, for initial thermal and (phase-diffused) coherent states. Quasiprobabilities are employed to characterize the state of the generated fields.Comment: 20 pages, 8 figures, to appear in Journal of Modern Optic

Improved limit on electron neutrino charge radius through a new evaluation of the weak mixing angle

We have obtained a new limit on the electron neutrino effective charge radius from a new evaluation of the weak mixing angle by a combined fit of all electron-(anti)neutrino electron elastic scattering measurements. Weak mixing angle is found to be sin^2 theta_W=0.259 \pm 0.025 in the low energy regime below 100 MeV. The electron neutrino charge radius squared is bounded to be in the range -0.13 10^-32 cm^2 < r^2 < 3.32 10^-32 cm^2 at 90 % C.L. Both results improve previously published analyses. We also discuss perspectives of future experiments to improve these constraints.Comment: 10 pages, 2 figures. Final published versio

Improved Contrast Sensitivity DVS and its Application to Event-Driven Stereo Vision

This paper presents a new DVS sensor with one order of magnitude improved contrast sensitivity over previous reported DVSs. This sensor has been applied to a bio-inspired event-based binocular system that performs 3D event-driven reconstruction of a scene. Events from two DVS sensors are matched by using precise timing information of their ocurrence. To improve matching reliability, satisfaction of epipolar geometry constraint is required, and simultaneously available information on the orientation is used as an additional matching constraint.Ministerio de Economía y Competitividad PRI-PIMCHI-2011-0768Ministerio de Economía y Competitividad TEC2009-10639-C04-01Junta de Andalucía TIC-609