total 3295took 0.10s

Type Ib and IIb supernova progenitors in interacting binary systemsJan 09 2017We explore properties of Type Ib and IIb SN progenitors that are produced by stable mass transfer in binary systems, using a new grid of stellar evolution models from an initial primary mass in the range of 10 - 18 $\mathrm{M_\odot}$ at solar and Large ... More

The Nickel Mass Distribution of Normal Type II SupernovaeFeb 01 2017May 16 2017Core-collapse supernova explosions expose the structure and environment of massive stars at the moment of their death. We use the global fitting technique of Pejcha & Prieto (2015a,b) to estimate a set of physical parameters of 19 normal Type II SNe, ... More

Photospheric Magnitude Diagrams for Type II Supernovae: A Promising Tool to Compute DistancesSep 10 2014We develop an empirical color-based standardization for Type II supernovae (SNe II), equivalent to the classical surface brightness method given in Wesselink (1969). We calibrate it with SNe II with host galaxy distance measured with Cepheids, and well-constrained ... More

Broad Band Polarimetry of Supernovae: SN1994D, SN1994Y, SN1994ae, SN1995D and SN 1995HFeb 29 1996We have made polarimetric observations of three Type Ia supernovae (SN Ia) and two type II supernovae (SN II). No significant polarization was detected for any of the SN Ia down to the level of 0.2\%, while polarization of order $1.0\%$ was detected for ... More

The Ultimate Light Curve of SN 1998bw/GRB 980425Jun 09 2011We present multicolor light curves of SN 1998bw which appeared in ESO184-G82 in close temporal and spacial association with GRB 980425. They are based on observations done at Cerro Tololo Inter-American Observatory and data from the literature. The CTIO ... More

Analysis of Late--time Light Curves of Type IIb, Ib and Ic SupernovaeNov 21 2014Apr 24 2015The shape of the light curve peak of radioactive--powered core--collapse "stripped--envelope" supernovae constrains the ejecta mass, nickel mass, and kinetic energy by the brightness and diffusion time for a given opacity and observed expansion velocity. ... More

Optical Spectroscopy of the Somewhat Peculiar Type IIb Supernova 2001igMar 24 2009May 22 2009Here we present previously unpublished optical spectra of supernova (SN) 2001ig, a Type IIb SN, from about a week after explosion until nearly one year later. The earliest spectrum consists of only a few broad absorption features, but soon more common ... 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

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

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

Archaeoastronomy and the orientation of old churchesApr 01 2016Cultural astronomy is an interdisciplinary area of research that studies how perceptions and concepts related to the sky are part of the worldview of a culture. One of its branches, archaeoastronomy, focuses on the material remains of past peoples and ... 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.

No firewalls in quantum gravity: the role of discreteness of quantum geometry in resolving the information loss paradoxOct 26 2014Jan 27 2015In an approach to quantum gravity where space-time arises from coarse graining of fundamentally discrete structures, black hole formation and subsequent evaporation can be described by a unitary evolution without the problems encountered by the standard ... More

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

Towards a microeconomic theory of the finance-driven business cycleDec 02 2013Jul 01 2015I sketch a program for a microeconomic theory of the main component of the business cycle as a recurring disequilibrium, driven by incompleteness of the financial market and by information asymmetries between borrowers and lenders. This proposal seeks ... More

On the Title of Moriarty's 'Dynamics of an Asteroid'Feb 23 2013Aug 05 2014We propose an explanation of the title of Prof. James Moriarty's treatise_Dynamics of an Asteroid_, a scientific work mentioned by Sherlock Holmes in_The Valley of Fear_ and prominently featured in Guy Ritchie's 2011 film_Sherlock Holmes: A Game of Shadows_. ... More

Self-oscillationSep 29 2011Dec 11 2012Physicists are very familiar with forced and parametric resonance, but usually not with self-oscillation, a property of certain dynamical systems that gives rise to a great variety of vibrations, both useful and destructive. In a self-oscillator, the ... More

Sprinkler Head Revisited: Momentum, Forces, and Flows in Machian PropulsionAug 23 2009Jun 27 2011Many experimenters, starting with Ernst Mach in 1883, have reported that if a device alternately sucks in and then expels a surrounding fluid, it moves in the same direction as if it only expelled fluid. This surprising phenomenon, which we call "Machian ... More

Realistic indirect spin-interactions between magnetic impurities on a metallic Pb(110) surfaceAug 29 2019Motivated by recent experiments, here we study the indirect interactions between magnetic impurities deposited on top of a clean Pb(110) surface induced by the underlying conduction electrons. Our approach makes use of \textit{ab initio} calculations ... More

Polarization Studies: testing explanations of the B -> phi K* puzzle and B -> V T decaysJun 30 2008It has been observed in B->phiK* and B^{0(+)}->rho^{0(+)}K^{*0} that the fraction of transverse decays, fT, and the fraction of longitudinal decays, fL, are roughly equal, in opposition to the naive expectation, fT/fL << 1. If one requires a single explanation ... More

The quantum walk temperatureAug 27 2011A thermodynamic theory is developed to describe the behavior of the entanglement between the coin and position degrees of freedom of the quantum walk on the line. This theory shows that, in spite of the unitary evolution, a steady state is established ... More

Loop Quantum Geometry: A primerJul 08 2005Jul 13 2005This is the written version of a lecture given at the ``VI Mexican School of Gravitation and Mathematical Physics" (Nov 21-27, 2004, Playa del Carmen, Mexico), introducing the basics of Loop Quantum Geometry. The purpose of the written contribution is ... More

Density effects on the pion dispersion relation at finite temperatureDec 20 2002We study the behavior of the pion dispersion relation in a pion medium at finite density and temperature, introducing a chemical potential to describe the finite pion number density. Such description is particularly important during the hadronic phase ... More

Chiral Ward identities and pion propagation at finite temperature in the linear sigma modelAug 16 2000Working within the linear sigma model at finite temperature, we construct effective one-loop vertices and propagators satisfying the chiral Ward identities, for small pion momentum and mass compared to the sigma mass. We obtain an expansion for the pion ... More

The dark matter dispersion tensor in perturbation theoryDec 22 2015Mar 07 2016We compute the dark matter velocity dispersion tensor up to third order in perturbation theory using the Lagrangian formalism, revealing growing solutions at the third and higher orders. Our results are general and can be used for any other perturbative ... More

Some geometric features of Berry's phaseMay 15 2007Jun 08 2007In this letter, we elaborate on the identification and construction of the differential geometric elements underlying Berry's phase. Berry bundles are built generally from the physical data of the quantum system under study. We apply this construction ... More

Heavy and Light Monopoles in Magnetic Reversion in Artificial Spin IceAug 30 2012This work makes a theoretical study of the dynamics of emergent elemental excitations in artificial spin ice systems with hexagonal geometry during the magnetic reversion of the system. The magnetic and physical parameters of the nanoislands that form ... More

The effect of the size of the system, aspect ratio and impurities concentration on the dynamic of emergent magnetic monopoles in artificial spin ice systemsAug 16 2012In this work we study the dynamical properties of a finite array of nanomagnets in artificial kagome spin ice at room temperature. The dynamic response of the array of nanomagnets is studied by implementing a "frustrated celular aut\'omata" (FCA), based ... More

Status, open problems and prospects of the decay B^+ -> l^+ nu_lDec 06 2010The study of rare B-decays at SuperB provides unique opportunities to understand the Standard Model and constrain new physics. We discuss the new physics potential of the leptonic B^+ -> l^+ nu_l decays from the proposed SuperB experiment with 75ab-1 ... More

Rare B decays Potential of SuperBNov 22 2010The study of rare B-decays at SuperB provides unique opportunities to understand the Standard Model and constrain new physics. It is discussed the new physics potential of the B -> K nu nu_bar and B -> K^{\ast} nu nu_bar system from the proposed SuperB ... More

The Spin Foam Approach to Quantum GravityMay 09 2012This article reviews the present status of the spin foam approach to the quantization of gravity. Special attention is payed to the pedagogical presentation of the recently introduced new models for four dimensional quantum gravity. The models are motivated ... More

The new spin foam models and quantum gravityMay 04 2012In this article we give a systematic definition of the recently introduced spin foam models for four dimensional quantum gravity reviewing the main results on their semiclassical limit on fixed discretizations.

On the regularization ambiguities in loop quantum gravitySep 29 2005One of the main achievements of LQG is the consistent quantization of the Wheeler-DeWitt equation which is free of UV problems. However, ambiguities associated to the intermediate regularization procedure lead to an apparently infinite set of possible ... More

A possible origin of the q=4/3 diquarkNov 14 2011Dec 03 2011Between the new physics candidates proposed to explain the $t \bar t$ asymmetry measured in the Tevatron, there are some scalar diquarks with electric charge +4/3. This kind of diquark is also needed to classify all the scalars of the supersymmetric standard ... More

Unbroken supersymmetry without new particlesOct 26 2009Nov 12 2009We consider Koide's equation for charged leptons jointly with hypotheses implied in the ancient Dual Quark-Gluon model. The focus is to motivate the possibility of a supersymmetric framework akin to the one of D=11 maximal supergravity.

Democritus as TaoistSep 25 2003While similarities do naturally exist between tao and other philosophical systems, for the specific case of Democritus we can argue also the chronological parallels, the parallels in the posterior development (alchemy and mathematics) and the textual ... More

A Short Lecture on DivergencesAug 25 2002We present some clues to the study of the renormalization group, at graduate level, as well as some bibliographical pointers to classical resources. Just the kind of things one had liked to hear when starting to study the subject.

Mass terms to break susy-like degenerationJun 15 2006We suggest a very simple but general operator to break mass degeneration between representations of the Poincare group having spin 1 and 1/2. A quantity very similar, at experimental 0.13 $\sigma$ level, to Weinberg's angle, appears during the process. ... More

Regularities in electromagnetic decay widthsMar 20 2006We revisit Sakurai's remark on the regularities of lepton-pair widths for mesons, extending the panorama to radiative $X \to \gamma \gamma$ and total decays. The regularities persist, and somehow surprisingly some of them seem to relate with Fermi's constant ... More

GUT angle minimises $Z^0$ decayNov 14 2005The GUT value of Weinberg's angle is also the value that minimises the total square matrix elements of $Z^0$ decay, independently of any GUT consideration, and thus the one that maximises the neutrino branching ratio against total width. We review the ... More

Around Poincare duality, in discrete spacesApr 28 2002We walk out the landscape of K-theoretic Poincare Duality for finite algebras. It paves the way to get continuum Dirac operators from discrete noncommutative manifolds.

A short derivation of Feynman formulaMar 14 1998The complex exponential weighting of Feynman formalism is seen to happen at the classical level. (Finiteness of) Feynman path integral formula is suspected then to appear as a consistency condition for the existence of certain Dirac measures over functional ... More

Hole probability for nodal sets of the cut-off Gaussian Free FieldFeb 26 2016Sep 02 2016Let ($\Sigma$, g) be a closed connected surface equipped with a riemannian metric. Let ($\lambda$ n) n$\in$N and ($\psi$ n) n$\in$N be the increasing sequence of eigenvalues and the sequence of corresponding L 2-normalized eigenfunctions of the laplacian ... More

Chandler wobble: Stochastic and deterministic dynamicsJun 09 2015Feb 25 2016We propose a model of the Earth's torqueless precession, the "Chandler wobble", as a self-oscillation driven by positive feedback between the wobble and the centrifugal deformation of the portion of the Earth's mass contained in circulating fluids. The ... More

Topics in particle physics and cosmology beyond the standard modelJul 29 2006We review the interpretation of gauge invariance as a mathematical redundancy required in a relativistic description of forces mediated by massless spin-1 and spin-2 particles. In this context we also review the Weinberg-Witten theorem and its implications. ... More

Composite Mediators and Lorentz ViolationSep 20 2004Jan 03 2005We briefly review the history and current status of models of particle interactions in which massless mediators are given, not by fundamental gauge fields as in the Standard Model, but by composite degrees of freedom of fermionic systems. Such models ... More

Spontaneous Breaking of Lorentz InvarianceNov 14 2003May 17 2004We describe how a stable effective theory in which particles of the same fermion number attract may spontaneously break Lorentz invariance by giving non-zero fermion number density to the vacuum (and therefore dynamically generating a chemical potential ... More

Talagrand's inequality in planar Gaussian field percolationMay 30 2019Jun 25 2019Let f be a stationary isotropic non-degenerate Gaussian field on R^2. Assume that f = q * W where q is both C^2 and L^2 and W is the L^2 white noise on R^2. We extend a result by Stephen Muirhead and Hugo Vanneuville by showing that, assuming that q * ... More

Bloch functions on the unit ball of a Banach spaceFeb 22 2018The space of Bloch functions on bounded symmetric domains is extended by considering Bloch functions $f$ on the unit ball $B_E$ of finite and infinite dimensional complex Banach spaces in two different ways: by extending the classical Bloch space considering ... More

Anomalies in local Weyl laws and applications to random topology at critical dimensionNov 07 2016Jun 20 2018Let $\mathcal{M}$ be a smooth manifold of positive dimension $n$ equipped with a smooth density $d\mu_{\mathcal{M}}$. Let $A$ be a polyhomogeneous elliptic pseudo-differential operator of positive order $m$ on $\mathcal{M}$ which is symmetric for the ... More

Status of Sterile Neutrino fits with Global DataOct 12 2017Feb 20 2018A number of short baseline neutrino oscillation experiments have observed an anomalous excess of neutrinos in the low energy range. This may hint towards the existence of additional neutrino mass splittings. If true, additional sterile (non-interacting) ... More

Twisted Affine Lie Algebras, Fusion Algebras, and Congruence SubgroupsNov 10 2018Nov 26 2018The space spanned by the characters of twisted affine Lie algebras admit the action of certain congruence subgroups of $SL(2,\mathbb{Z})$. By embedding the characters in the space spanned by theta functions, we study an $SL(2,\mathbb{Z})$-closure of the ... More

Rational Polygons as Rotation Sets of Generic Homeomorphisms of the Two-TorusAug 13 2012Aug 20 2012We prove the existence of an open and dense set D\subset? Homeo0(T2) (set of toral homeomorphisms homotopic to the identity) such that the rotation set of any element in D is a rational polygon. We also extend this result to the set of axiom A dif- feomorphisms ... More

Motion of the heavens: a pedagogical proposal for secondary education teachersMar 09 2009First part of a didactic sequence of activities on some topics of Astronomy, related mainly with the day and night cycle and the seasons, including the construction of a simplified solar system model and its use as a resource to discuss some common misconceptions ... More

Whither Does the Sun Rove?Apr 12 2011If one asked some friends where on the horizon they should expect to see the sunrise, half of the answers would be "in the east". Of course, something analogous would happen with the sunset and the west. However, sunrise and sunset virtually never occur ... More

Distribution of chirality in the quantum walk: Markov process and entanglementApr 07 2010Jun 11 2010The asymptotic behavior of the quantum walk on the line is investigated focusing on the probability distribution of chirality independently of position. The long-time limit of this distribution is shown to exist and to depend on the initial conditions, ... More

Fractional dynamics in the Lévy quantum kicked rotorApr 15 2008We investigate the quantum kicked rotor in resonance subjected to momentum measurements with a L\'evy waiting time distribution. We find that the system has a sub-ballistic behavior. We obtain an analytical expression for the exponent of the power law ... More

The Fibonacci quantum walk and its cassical trace mapFeb 15 2008We study the quantum walk in momentum space using a coin arranged in quasi-periodic sequences following a Fibonacci prescription. We build for this system a classical map based on the trace of the evolution operator. The sub-ballistic behavior of this ... More

Energy of test objects on black hole spacetimes: A brief reviewJul 04 2012Sep 06 2015In this paper, we review the issue of defining energy for test particles on a background stationary spacetime. We revisit the different notions of energy as defined by different observers. As is well known, the existence of a time-like isometry allows ... More

On Quasinormal Modes, Black Hole Entropy, and Quantum GeometryDec 30 2002Jan 07 2003Loop quantum gravity can account for the Bekenstein-Hawking entropy of a black hole provided a free parameter is chosen appropriately. Recently, it was proposed that a new choice of the Immirzi parameter could predict both black hole entropy and the frequencies ... More

rho^0 mass in a hot hadron gasOct 19 2004We study the behavior of the rho^0 vector mass during the hadronic phase of an ultra-relativistic heavy-ion collision at finite temperature. We show that scattering with the most abundant particles during this stage, namely, pions, kaons and nucleons, ... More

Effects of a charged Higgs boson in $B \rightarrow D^{(*)} τν$ decaysAug 30 2013Sep 25 2013In this talk I consider the current status of $B \rightarrow D^{(*)} \tau \nu$ decays in the context of two-Higgs-doublet models. The BaBar collaboration has reported an excess in semileptonic $b \rightarrow c \tau \nu$ transitions that has gathered recent ... More

Heavy quarks and tau leptons: New physics opportunitiesOct 29 2014In this talk I discuss the role of heavy quarks in new physics searches with tau leptons. I focus on new physics effects associated to the scalar sector which are naturally enhanced for the heaviest fermions due to the large hierarchy of the fermion masses. ... More

Anomalies in local Weyl laws and applications to random topology at critical dimensionNov 07 2016Let $\mathcal{M}$ be a smooth manifold of positive dimension $n$ equipped with a smooth density $d\mu_{\mathcal{M}}$. Let $A$ be a polyhomogeneous elliptic pseudo-differential operator of positive order $m$ on $\mathcal{M}$ which is symmetric for the ... More

The tree property at first and double successors of singular cardinals of uncountable cofinality with an arbitrary gapMay 03 2019Let $\mu$ be a regular cardinal and assume that there is a continuous sequence of cardinals $\langle \kappa_\xi:\,\xi<\mu\rangle$ such that $\kappa_0>\mu$ is a supercompact cardinal and for all $\xi<\mu$, $\kappa_{\xi+1}$ are also supercompact cardinals. ... More

Fixing the shadows while moving the gnomonApr 08 2016It is a common practice to fix a vertical gnomon and study the moving shadow cast by it. This shows our local solar time and gives us a hint regarding the season in which we perform the observation. The moving shadow can also tell us our latitude with ... More

Supersymmetric BCS: Effects of an external magnetic field and spatial fluctuations of the gapJan 04 2013Jul 15 2013Recently an N=1 supersymmetric model of BCS superconductivity was proposed realizing spontaneous symmetry breaking of a U(1)_R symmetry. Due to scalar contributions the superconducting phase transition turned out to be first order rather than second order ... More

Talagrand's inequality in planar Gaussian field percolationMay 30 2019Let f be a stationary isotropic non-degenerate Gaussian field on R^2. Assume that f = q * W where q is both C^2 and L^2 and W is the L^2 white noise on R^2. We extend a result by Stephen Muirhead and Hugo Vanneuville by showing that, assuming that q * ... More

Representations and $K$-theory of Discrete GroupsJan 01 1993Let $\Gamma$ be a discrete group of finite virtual cohomological dimension with certain finiteness conditions of the type satisfied by arithmetic groups. We define a representation ring for $\Gamma$, determined on its elements of finite order, which is ... More

Constructing and Deconstructing Group ActionsDec 19 2002We survey some results concerning finite group actions on products of spheres.

Buildings, group extensions and the cohomology of congruence subgroupsFeb 20 1997We use buildings and group extensions to compute lower bounds on the top Betti numbers for the cohomology of the level p congruence subgroups of SL(3,Z) and Sp(4,Z).

Eberhardt's inequality and recent loophole-free experimentsJul 14 2016Aug 08 2016Recent experiments using innovative optical detectors and techniques have strongly increased the capacity of testing the violation of the Bell's inequalities in the Nature. Most of them have used the Eberhardt's inequality (EI) to close the "detection" ... More

Large-scale tidal fields on primordial density perturbations ?Feb 17 1997We calculate the strength of the tidal field produced by the large-scale density field acting on primordial density perturbations in power law models. By analysing changes in the orientation of the deformation tensor, resulted from smoothing the density ... More

Tidal Shear on Density Perturbations and Galaxy FormationJun 05 1995The strenth of the tidal shear produced by the large-scale density field acting on primordial density perturbations is calculated in power law models. It is shown that the large-scale tidal field could, strongly affect the morphology, orientation and ... More

The 115 GeV signal from nuclear physicsMay 10 2004Jul 30 2004According standard models of nuclei, steepest variations of binding energy at the drip lines should happen for nuclear masses of 45, 68, 92, 115, 175 and 246 GeV. We explore the coincidence of these masses with another ones from well known HEP research ... More

Introduction to the Tangent GrupoidOct 23 1997We present some plausible definitions for the tangent grupoid of a manifold M, as well as some of the known applications of the structure. This is a kind of introductory note.

Standard Model Masses and Models of NucleiNov 30 2003May 10 2004We note an intriguing coincidence in nuclear levels, that the subshells responsible for doubly magic numbers happen to bracket nuclei at the energies of the Standard Model bosons. This could show that these bosons actually contribute to the effective ... More

Spin foam quantization of SO(4) Plebanski's actionMar 15 2002Nov 21 2002The goal of this work is two-fold. In the first part of this paper we regard classical Plebanski's action as a BF action supplemented by constraints. We introduce a spin foam model for Riemannian general relativity by systematically implementing these ... More

Nagata's compactification theorem for normal toric varieties over a valuation ring of rank oneAug 09 2016Apr 06 2017We 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 toric variety equivariantly. This extends a well known theorem of Sumihiro for toric ... More

Lectures on the Cohomology of Finite GroupsSep 28 2006In this paper we first survey some basic results in the cohomology of finite groups, and then discuss recent work on constructing free actions of finite groups on products of spheres.

Regularity of Stagnation Point-form Solutions of the Two-dimensional Euler EquationsJun 20 2013Sep 27 2014A class of semi-bounded solutions of the two-dimensional incompressible Euler equations satisfying either periodic or Dirichlet boundary conditions is examined. For smooth initial data, new blowup criteria in terms of the initial concavity profile is ... More

Weighted local Weyl laws for elliptic operatorsJan 22 2018Let $A$ be an elliptic pseudo-differential operator of order $m$ on a closed manifold $\mathcal{X}$ of dimension $n>0$, formally positive self-adjoint with respect to some positive smooth density $d\mu_\mathcal{X}$. Then, the spectrum of $A$ is made up ... More

The Fluidyne engineDec 26 2018The Fluidyne is a two-part hot-air engine, which has the peculiarity that both its power piston and displacer are liquids. Both parts operate in tandem with the common working gas (air) transferring energy from the displacer to the piston side, from which ... More

Spontaneous emergence of space stems ahead of negative leaders in lightning and long sparksSep 10 2019We investigate the emergence of space stems ahead of negative leaders. These are luminous spots that appear ahead of an advancing leader mediating the leader's stepped propagation. We show that space stems start as regions of locally depleted conductivity ... More

Quark masses from quark-gluon condensates in a modified perturbative QCDSep 19 2002In this note, it is argued that the mass matrix for the six quarks can be generated in first approximation by introducing fermion condensates on the same lines as was done before for gluons, within the modified perturbative expansion for QCD proposed ... More

Measurements in the Lévy quantum walkOct 05 2007We study the quantum walk subjected to measurements with a L\'evy waiting-time distribution. We find that the system has a sub-ballistic behavior instead of a diffusive one. We obtain an analytical expression for the exponent of the power law of the variance ... More

Quantum Superposition Principle and GeometryJul 29 2004Feb 22 2006If one takes seriously the postulate of quantum mechanics in which physical states are rays in the standard Hilbert space of the theory, one is naturally lead to a geometric formulation of the theory. Within this formulation of quantum mechanics, the ... More

Comments on area spectra in Loop Quantum GravityFeb 13 2004Feb 17 2004We examine and compare different area spectra that have been recently considered in Loop Quantum Gravity (LQG). In particular we focus our attention on a Equally Spaced (ES) spectrum operator introduced by Alekseev et. al. that has gained recent attention. ... More

Black holes and entropy in loop quantum gravity: An overviewJan 09 2009Black holes in equilibrium and the counting of their entropy within Loop Quantum Gravity are reviewed. In particular, we focus on the conceptual setting of the formalism, briefly summarizing the main results of the classical formalism and its quantization. ... More

Introduction to the Fock Quantization of the Maxwell FieldApr 15 1998In this article we give an introduction to the Fock quantization of the Maxwell field. At the classical level, we treat the theory in both the covariant and canonical phase space formalisms. The approach is general since we consider arbitrary (globally-hyperbolic) ... More

Then again, how often does the Unruh-DeWitt detector click if we switch it carefully?Nov 13 2006Apr 20 2007The transition probability in first-order perturbation theory for an Unruh-DeWitt detector coupled to a massless scalar field in Minkowski space is calculated. It has been shown recently that the conventional $i\epsilon$ regularisation prescription for ... More

In Medium modifications to rho from finite pion density effects and dilepton spectrumMay 15 2003The behavior of the pion dispersion relation in a pion medium is strongly modified by the introduction of a finite chemical potential associated to the finite pion number density. Such behavior is particularly important during the hadronic phase of a ... More

Quantum Disentanglement Eraser: an optical implementation using three-photon spontaneous decayJun 23 2015Oct 27 2015The 'disentanglement eraser' or 'entanglement restorer' scheme allows retrieving entanglement by erasing the information about the formation of a classical (or separable) state. It suggests an analogy between the pairs of properties: entangled-separable ... More

Quantum walk, entanglement and thermodynamic lawsMar 29 2015We consider an special dynamics of a quantum walk (QW) on a line. Initially, the walker localized at the origin of the line with arbitrary chirality, evolves to an asymptotic stationary state. In this stationary state a measurement is performed and the ... More