Results for "Alejandro Ibarra"

total 2247took 0.20s
Neutralino spectrum in top-down models of UHECRFeb 12 2002Jun 12 2002We calculate the cosmic ray spectrum of ultra high energy neutralinos that one should expect provided that the observed ultra high energy cosmic rays are produced by the decay of superheavy particles X, M_X>10^{12} GeV, in supersymmetric models. Our calculation ... More
Lepton flavour violation in future linear colliders in the long-lived stau NLSP scenarioJun 09 2006May 07 2007We analyze the prospects of observing lepton flavour violation in future e-e- and e+e- linear colliders in scenarios where the gravitino is the lightest supersymmetric particle, and the stau is the next-to-lightest supersymmetric particle. The signals ... More
Dark Matter Stability without New SymmetriesApr 02 2014Aug 28 2014The stability of dark matter is normally achieved by imposing extra symmetries beyond those of the Standard Model of Particle Physics. In this paper we present a framework where the dark matter stability emerges as a consequence of the Standard Model ... More
Dirac dark matter with a charged mediator: a comprehensive one-loop analysis of the direct detection phenomenologyMar 11 2015May 29 2015We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced ... More
Novel Gamma-ray Spectral Features in the Inert Doublet ModelJun 19 2013Sep 24 2013The inert doublet model contains a neutral stable particle which is an excellent dark matter candidate. We discuss in this paper the indirect signatures of this model in gamma-rays when the dark matter mass is larger than the $W$ boson mass. We show that, ... More
Systematic Approach to Gauge-Invariant Relations between Lepton Flavor Violating ProcessesOct 28 2004Nov 18 2004We analyze four-lepton contact interactions that lead to lepton flavor violating processes, with violation of individual family lepton number but total lepton number conserved. In an effective Lagrangian framework, the assumption of gauge invariance leads ... More
Dark matter annihilations and decays after the AMS-02 positron measurementsSep 10 2013Mar 27 2014The AMS-02 collaboration has recently presented measurements of excellent quality of the cosmic electron and positron fluxes as well as the positron fraction. We use the measurements of the positron flux to derive, for the first time, limits on the dark ... More
DAMA confronts null searches in the effective theory of dark matter-nucleon interactionsFeb 12 2016May 19 2016We examine the dark matter interpretation of the modulation signal reported by the DAMA experiment from the perspective of effective field theories displaying Galilean invariance. We consider the most general effective coupling leading to the elastic ... More
Higher order dark matter annihilations in the Sun and implications for IceCubeFeb 18 2014Dark matter particles captured in the Sun would annihilate producing a neutrino flux that could be detected at the Earth. In some channels, however, the neutrino flux lies in the MeV range and is thus undetectable at IceCube, namely when the dark matter ... More
High-energy neutrino signals from the Sun in dark matter scenarios with internal bremsstrahlungNov 06 2013Dec 18 2013We investigate the prospects to observe a high energy neutrino signal from dark matter annihilations in the Sun in scenarios where the dark matter is a Majorana fermion that couples to a quark and a colored scalar via a Yukawa coupling. In this minimal ... More
Dark matter production from Goldstone boson interactions and implications for direct searches and dark radiationOct 23 2013Nov 07 2013The stability of the dark matter particle could be attributed to the remnant $Z_2$ symmetry that arises from the spontaneous breaking of a global U(1) symmetry. This plausible scenario contains a Goldstone boson which, as recently shown by Weinberg, is ... More
A novel approach to derive halo-independent limits on dark matter propertiesJun 10 2015Sep 23 2015We propose a method that allows to place an upper limit on the dark matter elastic scattering cross section with nucleons which is independent of the velocity distribution. Our approach combines null results from direct detection experiments with indirect ... More
Dark matter decays from non-minimal coupling to gravityMar 11 2016We consider the Standard Model extended with a dark matter particle in curved spacetime, motivated by the fact that the only current evidence for dark matter is through its gravitational interactions, and we investigate the impact on the dark matter stability ... More
Direct detection of fermion dark matter in the radiative seesaw modelJan 06 2016We consider the scenario in the radiative seesaw model where the dark matter particle is the lightest $Z_2$-odd fermion. We identify the regions of the parameter space of the model compatible with neutrino oscillation data, with the upper limits from ... More
Probing the Inert Doublet Dark Matter Model with Cherenkov TelescopesDec 09 2015Feb 16 2016We present a detailed study of the annihilation signals of the inert dark matter doublet model in its high mass regime. Concretely, we study the prospects to observe gamma-ray signals of the model in current and projected Cherenkov telescopes taking into ... More
A new mechanism of sterile neutrino dark matter productionFeb 08 2018We consider a scenario where the dark matter candidate is a sterile neutrino with sizable self-interactions, described by a dimension-six operator, and with negligible interactions with the Standard Model. The relic abundance is set by the freeze-out ... More
On the spin-dependent sensitivity of XENON100Nov 19 2012Mar 12 2013The latest XENON100 data severely constrains dark matter elastic scattering off nuclei, leading to impressive upper limits on the spin-independent cross-section. The main goal of this paper is to stress that the same data set has also an excellent \emph{spin-dependent} ... More
Electrochemical lithium intercalation in nanosized manganese oxidesNov 12 2007X-ray amorphous manganese oxides were prepared by reduction of sodium permanganate by lithium iodide in aqueous medium (MnOx-I) and by decomposition of manganese carbonate at moderate temperature (MnOx-C). TEM showed that these materials are not amorphous, ... More
A radiative model with a naturally mild neutrino mass hierarchyAug 15 2012Many neutrino mass models postulate the existence of at least two extra fermions in order to account for the measured solar and atmospheric mass splittings. In these models, however, the predicted hierarchy between the two mass splittings is generically ... More
Prospects of antideuteron detection from dark matter annihilations or decays at AMS-02 and GAPSSep 25 2012May 10 2013The search for cosmic antideuterons has been proposed as a promising method to indirectly detect dark matter, due to the very small background flux from spallations expected at the energies relevant to experiments. The antideuteron flux from dark matter ... More
Determination of the Cosmic Antideuteron Flux in a Monte Carlo approachJan 16 2013We investigate in this paper the antideuteron flux produced in high energy collisions of cosmic rays with the interstellar matter. We employ the Monte Carlo generator DPMJET-III together with the coalescence model to simulate, in an event-by-event basis, ... More
Probing lepton flavour violation in slepton NLSP scenariosDec 16 2004Dec 29 2004In supersymmetric models where the gravitino is the lightest superparticle, the next-to-lightest superparticle (NLSP) is long-lived, and hence could be collected and studied in detail. We study the prospects of direct detection of lepton flavour violation ... More
Decaying Dark Matter and the PAMELA AnomalyNov 10 2008Astrophysical and cosmological observations do not require the dark matter particles to be absolutely stable. If they are indeed unstable, their decay into positrons might occur at a sufficiently large rate to allow the indirect detection of dark matter ... More
Gamma Ray Spectrum from Gravitino Dark Matter DecaySep 28 2007Jan 23 2008Gravitinos are very promising candidates for the cold dark matter of the Universe. Interestingly, to achieve a sufficiently long gravitino lifetime, R-parity conservation is not required, thus preventing any dangerous cosmological influence of the next-to-lightest ... More
Antideuterons from Dark Matter DecayApr 08 2009Apr 24 2009Recent observations of a large excess of cosmic-ray positrons at high energies have raised a lot of interest in leptonic decay modes of dark matter particles. Nevertheless, dark matter particles in the Milky Way halo could also decay hadronically, producing ... More
Antimatter Signatures of Gravitino Dark Matter DecayApr 29 2008The scenario of gravitino dark matter with broken R-parity naturally reconciles three paradigms that, albeit very well motivated separately, seem to be in mutual conflict: supersymmetric dark matter, thermal leptogenesis and standard Big Bang nucleosynthesis. ... More
Antihelium from Dark MatterJan 10 2014Mar 19 2014Cosmic-ray anti-nuclei provide a promising discovery channel for the indirect detection of particle dark matter. Hadron showers produced by the pair-annihilation or decay of Galactic dark matter generate anti-nucleons which can in turn form light anti-nuclei. ... More
Signatures from Scalar Dark Matter with a Vector-like Quark MediatorNov 13 2015Feb 02 2016We present a comprehensive study of a model where the dark matter is composed of a singlet real scalar that couples to the Standard Model predominantly via a Yukawa interaction with a light quark and a colored vector-like fermion. A distinctive feature ... More
Radiative Generation of Quark Masses and Mixing Angles in the Two Higgs Doublet ModelMar 10 2014Jul 04 2014We present a framework to generate the quark mass hierarchies and mixing angles by extending the Standard Model with one extra Higgs doublet. The charm and strange quark masses are generated by small quantum effects, thus explaining the hierarchy between ... More
Lepton parameters in the see-saw model extended by one extra Higgs doubletSep 17 2014We investigate the radiative generation of lepton masses and mixing angles in the Standard Model extended by one right-handed neutrino and one extra Higgs doublet. We assume approximate rank-1 Yukawa couplings at a high energy scale and we calculate the ... More
Decaying Dark Matter in Light of the PAMELA and Fermi LAT DataJun 08 2009Dec 07 2009A series of experiments measuring high-energy cosmic rays have recently reported strong indications for the existence of an excess of high-energy electrons and positrons. If interpreted in terms of the decay of dark matter particles, the PAMELA measurements ... More
Detecting Gamma-Ray Anisotropies from Decaying Dark Matter: Prospects for Fermi LATSep 18 2009Dec 14 2009Decaying dark matter particles could be indirectly detected as an excess over a simple power law in the energy spectrum of the diffuse extragalactic gamma-ray background. Furthermore, since the Earth is not located at the center of the Galactic dark matter ... More
Signatures of Majorana dark matter with t-channel mediatorsMar 04 2015Apr 23 2015Three main strategies are being pursued to search for non-gravitational dark matter signals: direct detection, indirect detection and collider searches. Interestingly, experiments have reached sensitivities in these three search strategies which may allow ... More
Dark matter decay through gravity portalsNov 02 2016Motivated by the fact that, so far, the whole body of evidence for dark matter is of gravitational origin, we study the decays of dark matter into Standard Model particles mediated by gravity portals, i.e., through nonminimal gravitational interactions ... More
Dark matter annihilations into two light fermions and one gauge boson: general analysis and antiproton constraintsDec 21 2011Jul 11 2013We study in this paper the scenario where the dark matter is constituted by Majorana particles which couple to a light Standard Model fermion and an extra scalar via a Yukawa coupling. In this scenario, the annihilation rate into the light fermions with ... More
Cosmological and astrophysical signatures of dark matter annihilations into pseudo-Goldstone bosonsDec 12 2013Feb 19 2014We investigate a model where the dark matter particle is a chiral fermion field charged under a global $U(1)$ symmetry which is assumed to be spontaneously broken, leading to a pseudo-Goldstone boson (PGB). We argue that the dark matter annihilation into ... More
Future sensitivity of neutrino telescopes to dark matter annihilations from the cosmic diffuse neutrino signalDec 14 2014May 14 2015Cosmological observations and cold dark matter N-body simulations indicate that our Universe is populated by numerous halos, where dark matter particles annihilate, potentially producing Standard Model particles. In this paper we calculate the contribution ... More
Dark matter constraints from box-shaped gamma-ray featuresApr 30 2012Jul 24 2012The observation of a sharp spectral feature in the gamma-ray sky would be one of the cleanest ways to identify dark matter and pinpoint its properties. Over the years a lot of attention has been paid to two specific features, namely gamma-ray lines and ... More
Constraints on Hadronically Decaying Dark MatterMay 30 2012Aug 23 2012We present general constraints on dark matter stability in hadronic decay channels derived from measurements of cosmic-ray antiprotons.We analyze various hadronic decay modes in a model-independent manner by examining the lowest-order decays allowed by ... More
Indirect Searches for Decaying Dark MatterJul 24 2013Nov 07 2013Numerous observations point towards the existence of an unknown elementary particle with no electromagnetic interactions, a large population of which was presumably produced in the early stages of the history of the Universe. This so-called dark matter ... More
Heavy Neutrinos at Future CollidersJan 07 2016We discuss the current status and future prospects of heavy neutrino searches at the energy frontier, which might play an important role in vindicating the simplest seesaw paradigm as the new physics responsible for neutrino mass generation. After summarizing ... More
Antiproton constraints on dark matter annihilations from internal electroweak bremsstrahlungMay 26 2011If the dark matter particle is a Majorana fermion, annihilations into two fermions and one gauge boson could have, for some choices of the parameters of the model, a non-negligible cross-section. Using a toy model of leptophilic dark matter, we calculate ... More
Gamma-Rays from Decaying Dark MatterSep 14 2007Oct 11 2007We study the prospects for detecting gamma-rays from decaying Dark Matter (DM), focusing in particular on gravitino DM in R-parity breaking vacua. Given the substantially different angular distribution of the predicted gamma-ray signal with respect to ... More
Gamma-ray triangles: a possible signature of asymmetric dark matter in indirect searchesApr 07 2016We introduce a new type of gamma-ray spectral feature, which we denominate gamma-ray triangle. This spectral feature arises in scenarios where dark matter self-annihilates via a chiral interaction into two Dirac fermions, which subsequently decay in flight ... More
Supersymmetric Leptogenesis with a Light Hidden SectorApr 27 2010Jun 25 2010Supersymmetric scenarios incorporating thermal leptogenesis as the origin of the observed matter-antimatter asymmetry generically predict abundances of the primordial elements which are in conflict with observations. In this paper we propose a simple ... More
Gamma-Ray Lines from Radiative Dark Matter DecayNov 16 2010Mar 08 2011The decay of dark matter particles which are coupled predominantly to charged leptons has been proposed as a possible origin of excess high-energy positrons and electrons observed by cosmic-ray telescopes PAMELA and Fermi LAT. Even though the dark matter ... More
Neutrino Signals from Dark Matter DecayDec 17 2009Apr 20 2010We investigate different neutrino signals from the decay of dark matter particles to determine the prospects for their detection, and more specifically if any spectral signature can be disentangled from the background in present and future neutrino observatories. ... More
Probing the stability of superheavy dark matter particles with high-energy neutrinosMay 23 2012Mar 07 2013Two of the most fundamental properties of the dark matter particle, the mass and the lifetime, are only weakly constrained by the astronomical and cosmological evidence of dark matter. We derive in this paper lower limits on the lifetime of dark matter ... More
Internal bremsstrahlung signatures in light of direct dark matter searchesJun 26 2013Dec 23 2013Although proposed long ago, the search for internal bremsstrahlung signatures has only recently been made possible by the excellent energy resolution of ground-based and satellite-borne gamma-ray instruments. Here, we investigate thoroughly the current ... More
Majorana Dark Matter with a Coloured Mediator: Collider vs Direct and Indirect SearchesMar 18 2014We investigate the signatures at the Large Hadron Collider of a minimal model where the dark matter particle is a Majorana fermion that couples to the Standard Model via one or several coloured mediators. We emphasize the importance of the production ... More
Closing in on mass-degenerate dark matter scenarios with antiprotons and direct detectionJul 05 2012Nov 08 2012Over the last years both cosmic-ray antiproton measurements and direct dark matter searches have proved particularly effective in constraining the nature of dark matter candidates. The present work focusses on these two types of constraints in a minimal ... More
Intense Gamma-Ray Lines from Hidden Vector Dark Matter DecayDec 22 2009Mar 16 2010Scenarios with hidden, spontaneously broken, non-abelian gauge groups contain a natural dark matter candidate, the hidden vector, whose longevity is due to an accidental custodial symmetry in the renormalizable Lagrangian. Nevertheless, non-renormalizable ... More
Probing Gravitino Dark Matter with PAMELA and FermiJun 05 2009Aug 31 2009We analyze the cosmic-ray signatures of decaying gravitino dark matter in a model independent way based on an operator analysis. Thermal leptogenesis and universal boundary conditions at the GUT scale restrict the gravitino mass to be below 600 GeV. Electron ... More
Sharp Gamma-ray Spectral Features from Scalar Dark Matter AnnihilationsMay 27 2014The search for sharp features in the gamma-ray spectrum is a promising approach to identify a signal from dark matter annihilations over the astrophysical backgrounds. In this paper we investigate the generation of gamma-ray lines and internal bremsstrahlung ... More
Gamma-ray triangles: a possible signature of asymmetric dark matter in indirect searchesApr 07 2016Nov 12 2016We introduce a new type of gamma-ray spectral feature, which we denominate gamma-ray triangle. This spectral feature arises in scenarios where dark matter self-annihilates via a chiral interaction into two Dirac fermions, which subsequently decay in flight ... More
Probing the scotogenic FIMP at the LHCNov 29 2016We analyse the signatures at the Large Hadron Collider (LHC) of the scotogenic model, when the lightest $Z_2$-odd particle is a singlet fermion and a feebly interacting massive particle (FIMP). We further assume that the singlet fermion constitutes the ... More
Gravitino Dark Matter in R-Parity Breaking VacuaFeb 19 2007Oct 27 2008We show that in the case of small R-parity and lepton number breaking couplings, primordial nucleosynthesis, thermal leptogenesis and gravitino dark matter are naturally consistent for gravitino masses m_{3/2} \gsim 5 GeV. We present a model where R-parity ... More
Antideuterons in cosmic rays: sources and discovery potentialOct 01 2016Antibaryons are produced in our Galaxy in collisions of high energy cosmic rays with the interstellar medium and in old supernova remnants, and possibly, in exotic sources such as primordial black hole evaporation or dark matter annihilations and decays. ... More
Fermi LAT Search for Internal Bremsstrahlung Signatures from Dark Matter AnnihilationMar 06 2012Aug 27 2014A commonly encountered obstacle in indirect searches for galactic dark matter is how to disentangle possible signals from astrophysical backgrounds. Given that such signals are most likely subdominant, the search for pronounced spectral features plays ... More
Unstable Gravitino Dark Matter and Neutrino FluxSep 29 2008Jan 21 2009The gravitino is a promising supersymmetric dark matter candidate which does not require exact R-parity conservation. In fact, even with some small R-parity breaking, gravitinos are sufficiently long-lived to constitute the dark matter of the Universe, ... More
Gamma-ray boxes from axion-mediated dark matterMar 26 2013Apr 08 2016We compute the gamma-ray output of axion-mediated dark matter and derive the corresponding constraints set by recent data. In such scenarios the dark matter candidate is a Dirac fermion that pair-annihilates into axions and/or scalars. Provided that the ... More
Prospects of Heavy Neutrino Searches at Future Lepton CollidersMar 18 2015Sep 21 2015We discuss the future prospects of heavy neutrino searches at next generation lepton colliders. In particular, we focus on the planned electron-positron colliders, operating in two different beam modes, namely, $e^+e^-$ and $e^-e^-$. In the $e^+e^-$ beam ... More
On the sensitivity of CTA to gamma-ray boxes from multi-TeV dark matterMar 23 2015Jul 06 2016Collider, direct and indirect searches for dark matter have typically little or no sensitivity to weakly interacting massive particles (WIMPs) with masses above a few TeV. This rather unexplored regime can however be probed through the search for distinctive ... More
Gamma-rays from Heavy Minimal Dark MatterJul 20 2015Oct 20 2015We consider the annihilation into gamma rays of Minimal Dark Matter candidates in the fermionic 5-plet and scalar 7-plet representations of $SU(2)_L$, taking into account both the Sommerfeld effect and the internal bremsstrahlung. Assuming the Einasto ... More
Sociophysics in the mexican case (Sociofísica en el caso mexicano)Jun 25 2014The availability of electoral data in electronic format allowed to physicist and mathematicians their own analysis. Beyond theoretical models for electoral processes, new regularities had been found in the data analysis of many countries and many elections. ... More
Hidden gauginos of an unbroken U(1): Cosmological constraints and phenomenological prospectsSep 18 2008We study supersymmetric scenarios where the dark matter is the gaugino of an unbroken hidden U(1) which interacts with the visible world only via a small kinetic mixing with the hypercharge. Strong constraints on the parameter space can be derived from ... More
Einstein's first gravitational field equation 101 years latterJan 10 2014We review and strengthen the arguments given by Einstein to derive his first gravitational field equation for static fields and show that, although it was ultimately rejected, it follows from General Relativity (GR) for negligible pressure. Using this ... More
On a state model for the SO(2n) Kauffman polynomialApr 17 2013F. Jaeger presented the two-variable Kauffman polynomial of an unoriented link L as a weighted sum of HOMFLY-PT polynomials of oriented links associated with L. Murakami, Ohtsuki and Yamada (MOY) used planar graphs and a recursive evaluation of these ... More
Can the cosmological constant undergo abrupt changes?Sep 27 2005The existence of a simple spherically symmetric and static solution of the Einstein equations in the presence of a cosmological constant vanishing outside a definite value of the radial distance is investigated. A particular succession of field configurations, ... More
Precession of the Equinoxes: a pedagogical proposal for secondary education teachersMar 09 2009Second part of a didactic sequence of activities on some topics of Astronomy, related mainly with the real shape of the Earth, the gravitational interactions between our planet and other celestial bodies, and the resulting movement of the rotational axis ... More
Driving quantum walk spreading with the coin operatorJul 31 2009Oct 08 2009We generalize the discrete quantum walk on the line using a time dependent unitary coin operator. We find an analytical relation between the long-time behaviors of the standard deviation and the coin operator. Selecting the coin time sequence allows to ... More
Quantum games via search algorithmsSep 14 2006Feb 15 2007We build new quantum games, similar to the spin flip game, where as a novelty the players perform measurements on a quantum system associated to a continuous time search algorithm. The measurements collapse the wave function into one of the two possible ... More
Toward the classification of cohomology-free vector fieldsJun 27 2007Jul 11 2007In 1984, Anatole Katok conjectured that the only closed orientable manifolds that support cohomology-free vector fields are tori and these vector fields are smoothly conjugated to Diophantine (constant) ones. In this work we present a proof of Katok conjecture ... More
Flashes of noncommutativityFeb 24 2003Noncommutativity lays hidden in the proofs of classical dynamics. Modern frameworks can be used to bring it to light: *-products, groupoids, q-deformed calculus, etc.
Rhythmos, Diathige, TropeJun 26 2000Nov 29 2000It is argued that properties of Democritus' atoms parallel those of volume forms in differential geometry. This kind of atoms has not "size" of finite magnitude. ----- Se arguye que las propiedades de los atomos de Democrito son paralelas a las de sus ... More
Anomaly-driven decay of massive vector bosonsJul 12 2005We inquire if the total decay rate of neutral vector mesons can contain relevant off-shell contributions from the triangle anomaly. The answer seems to be affirmative for the case of J/Psi, and as a byproduct we get estimates of the decay width for neutral ... More
Distance to the drip linesJul 30 2004It can be found that with the adequate measure, the beta stability line is equidistant from neutron and proton drip lines. We explore this fact and its predictive potentiality in the simplest case, the classic liquid drop formula.
Some minor examples on discrete geometryApr 20 2004Mar 14 2005Assuming a minimum value for area measurement, the emergence of quantum mechanics can be easily motivated from naive consideration of gravitational force. Here we provide some pedagogical examples and extensions. At the same time, the role of Planck mass ... More
Discrete spectral triples converging to dirac operatorsMar 15 2002Mar 17 2002We exhibit some series of discrete spectral triples converging to the canonical spectral triple of a finite dimensional manifold. Thus the non-go theorem of Goekeler and Schuecker is reasonably bypassed.
A Generalized Montgomery Phase Formula for Rotating Self Deforming BodiesNov 20 2006We study the motion of self deforming bodies with non zero angular momentum when the changing shape is known as a function of time. The conserved angular momentum with respect to the center of mass, when seen from a rotating frame, describes a curve on ... More
On heat flow and non-reciprocitySep 20 2000Heat transfer properties in non-reciprocal systems are discussed. An ideal experiment employing microwave or optical isolators is considered in order to investigate the possibility for a spontaneous transfer of energy between two black bodies at common ... More
Finiteness of a spinfoam model for euclidean quantum general relativityNov 16 2000We prove that a certain spinfoam model for euclidean quantum general relativity, recently defined, is finite: all its all Feynman diagrams converge. The model is a variant of the Barrett-Crane model, and is defined in terms of a field theory over SO(4) ... More
Spin Foam Models for Quantum GravityJan 27 2003Feb 14 2003In this article we review the present status of the spin foam formulation of non-perturbative (background independent) quantum gravity. The article is divided in two parts. In the first part we present a general introduction to the main ideas emphasizing ... More
A Quadratic Approximation for the Optimal Power Flow in Power Distribution SystemsApr 23 2015This paper presents a quadratic approximation for the optimal power flow in power distributions systems. The proposed approach is based on a linearized load flow which is valid for power distribution systems including three-phase unbalanced operation. ... More
Tatami Maker: A combinatorially rich mechanical game boardJan 25 2013Mar 18 2013Japanese tatami mats are often arranged so that no four mats meet. This local restriction imposes a rich combinatorial structure when applied to monomino-domino coverings of rectilinear grids. We describe a modular, mechanical game board, prototyped with ... More
Cosmological Models in Modified f(R) Gravity TheoriesNov 11 2012The actual accelerated expansion of the universe continues being a mystery in physics. Some models had been proposed for this explanations, among them the dark energy, which however has problems of experimental character as well as theoretical. Other ... More
Meridional Transport in the Atmospheres of Earth and MarsNov 21 2015As we continue to discover terrestrial exoplanets, many with orbital and planetary characteristics drastically different from anything encountered in our solar system, we are likely to encounter 'exotic' atmospheric transport processes. As an example, ... More
Propagation of a binary signal along a chain of triangular graphane nanoclustersNov 25 2013In this paper, we study the dynamic properties of a linear array of graphane triangular molecules that transmit a binary signal. The electronic properties of nanoclusters are studied using calculations based on first principles, with hybrid potentials. ... More
Nagata's compactification theorem for normal toric varieties over a valuation ring of rank oneAug 09 2016We prove, using invariant Zariski-Riemann spaces, that every normal toric variety over a valuation ring of rank one can be embedded as an open dense subset into a proper normal toric variety equivariantly. This extends a well known theorem of Sumihiro ... More
Implications of Higgs data for the electroweak chiral LagrangianOct 03 2016In this talk I discuss the interpretation of LHC Higgs measurements within the electroweak chiral Lagrangian, paying particular attention to the role of power counting.
Nonstandard CP violation in B --> D_s D^0π^0 decaysDec 03 2004We study the possibility of measuring nonstandard CP violation effects through Dalitz plot analysis in B --> D_s D^0\pi^0 decays. The accuracy in the extraction of CP violating phases is analyzed by performing a Monte Carlo simulation of the decays, and ... More
Generalized Jaynes-Cummings model as a quantum search algorithmJun 05 2009We propose a continuous time quantum search algorithm using a generalization of the Jaynes-Cummings model. In this model the states of the atom are the elements among which the algorithm realizes the search, exciting resonances between the initial and ... More
On cohomological $C^0$-(in)stabilitySep 20 2012After Katok, a homeomorphism $f\colon M\to M$ is said to be cohomologically $C^0$-stable when its space of real $C^0$-coboundaries is closed in $C^0(M)$. In this short note we completely classify cohomologically $C^0$-stable homeomorphisms, showing that ... More
On the geometry of quantum constrained systemsJan 08 2008Jun 17 2008The use of geometric methods has proved useful in the hamiltonian description of classical constrained systems. In this note we provide the first steps toward the description of the geometry of quantum constrained systems. We make use of the geometric ... More
Supersymmetry with composite bosonsDec 05 2005We note that hadronic susy (empirical quark-diquark) symmetry can be expanded into the lepton sector, and that for three generations the counting of degrees of freedom is the one we need to build charged supermultiplets. For this to cure hierarchy, Higgs ... More
Critical dimension of Spectral TriplesSep 02 2004It is open the possibility of imposing requisites to the quantisation of Connes' Spectral Triples in such a way that a critical dimension D=26 appears.
Lessons from Numerical AnalysisAug 19 2001It is reviewed how Renormalization Group, species doubling and CKM mixing are known to appear in numerical analysis: Butcher group, parasitic solutions and higher order methods
Dream of a Christmas lectureJan 16 2000We recall the origins of differential calculus from a modern perspective. This lecture should be a victory song, but the pain makes it to sound more as an oath for vendetta, coming from Syracuse two milenia before.
The spin-foam-representation of loop quantum gravityJan 23 2006The problem of background independent quantum gravity is the problem of defining a quantum field theory of matter and gravity in the absence of an underlying background geometry. Loop quantum gravity (LQG) is a promising proposal for addressing this difficult ... More
Is the Tsallis q-mean value instable?Oct 27 2010The recent argue about the existence of an instability in the definition of the mean value appearing in the Tsallis non extensive Statistical Mechanic is reconsidered. Here, it is simply underlined that the pair of probability distributions employed in ... More