Results for "Felippe A. S. Barbosa"

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Quantum state engineering of light with continuous-wave optical parametric oscillatorsJul 01 2014The ability to engineer the quantum state of traveling optical fields is a central requirement for quantum information science and technology, including quantum communication, computing and metrology. In this video article, we describe the reliable generation ... More
Quantum state reconstruction of spectral field modes: homodyne and resonator detection schemesOct 09 2013Nov 21 2013We revisit the problem of quantum state reconstruction of light beams from the photocurrent quantum noise. As is well-known, but often overlooked, two longitudinal field modes contribute to each spectral component of the photocurrent (sideband modes). ... More
On-chip thermo-optic tuning of suspended microresonatorsMar 27 2017Suspended optical microresonators are promising devices for on-chip photonic applications such as radio-frequency oscillators, optical frequency combs, and sensors. Scaling up these devices demand the capability to tune the optical resonances in an integrated ... More
Beyond spectral homodyne detection: complete quantum measurement of spectral modes of lightAug 26 2013Nov 21 2013Spectral homodyne detection, a widely used technique for measuring quantum properties of light beams, cannot retrieve all the information needed to reconstruct the quantum state of spectral field modes. We show that full quantum state reconstruction can ... More
Breaking the Loss Limitation of On-chip High-confinement ResonatorsSep 27 2016On-chip optical resonators have the promise of revolutionizing numerous fields including metrology and sensing; however, their optical losses have always lagged behind their larger discrete resonator counterparts based on crystalline materials and flowable ... More
Visible Nonlinear PhotonicsJul 10 2019Over the past decade, remarkable advances have been realized in chip-based nonlinear photonic devices for classical and quantum applications in the near- and mid-infrared regimes. However, few demonstrations have been realized in the visible and near-visible ... More
Singular genuine rigidityMar 16 2018Dec 08 2018We extend the concept of genuine rigidity of submanifolds by allowing mild singularities, mainly to obtain new global rigidity results and unify the known ones. As one of the consequences, we simultaneously extend and unify Sacksteder and Dajczer-Gromoll ... More
Exploring six modes of an optical parametric oscillatorOct 09 2017Feb 20 2018We measure the complete quantum state for six modes of the electromagnetic field produced by an optical parametric oscillator. The investigation involves the sideband of the intense pump, signal, and idler fields generated by stimulated parametric downconversion ... More
Evolution of galactic magnetic fieldsSep 27 2018Dec 05 2018We study the cosmic evolution of the magnetic fields of a large sample of spiral galaxies in a cosmologically representative volume by employing a semi-analytic galaxy formation model and numerical dynamo solver in tandem. We start by deriving time- and ... More
A large change in the predicted number of small halos due to a small amplitude oscillating inflaton potentialJun 10 2010A smooth inflaton potential is generally assumed when calculating the primordial power spectrum, implicitly assuming that a very small oscillation in the inflaton potential creates a negligible change in the predicted halo mass function. We show that ... More
Strictly positive definite kernels on two-point compact homogeneous spacesMay 04 2015Oct 18 2015We present a necessary and sufficient condition for the strict positive definiteness of a real, continuous, isotropic and positive definite kernel on a two-point compact homogeneous space. The characterization adds to others previously obtained by D. ... More
Strict positive definiteness on a product of compact two-point homogeneous spacesMay 23 2016We present an explicit characterization for the real, continuous, isotropic and strictly positive definite kernels on a product of compact two-point homogeneous spaces, in the cases in which at least one of the spaces is a sphere of dimension greater ... More
Differentiable positive definite functions on two-point homogeneous spacesApr 29 2015In this paper we study continuous kernels on compact two point homogeneous spaces which are positive definite and zonal (isotropic). Such kernels were characterized by R. Gangolli some forty years ago and are very useful for solving scattered data interpolation ... More
Generalized Convolution Roots of Positive Definite Kernels on Complex SpheresOct 13 2014Feb 13 2015Convolution is an important tool in the construction of positive definite kernels on a manifold. This contribution provides conditions on an $L^2$-positive definite and zonal kernel on the unit sphere of $\mathbb{C}^q$ in order that the kernel can be ... More
Galactic magnetic fields and hierarchical galaxy formationJan 04 2015Apr 10 2015A framework is introduced for coupling the evolution of galactic magnetic fields sustained by the mean-field dynamo with the formation and evolution of galaxies in cold dark matter cosmology. Estimates of the steady-state strength of the large-scale and ... More
Constraints on galaxy formation models from the galaxy stellar mass function and its evolutionSep 22 2016Dec 19 2016We explore the parameter space of the semi-analytic galaxy formation model GALFORM, studying the constraints imposed by measurements of the galaxy stellar mass function (GSMF) and its evolution. We use the Bayesian Emulator method to quickly eliminate ... More
Constraints on galaxy formation models from the galaxy stellar mass function and its evolutionSep 22 2016We explore the parameter space of the semi-analytic galaxy formation model GALFORM, studying the constraints imposed by measurements of the galaxy stellar mass function (GSMF) and its evolution. We use the Bayesian Emulator method to quickly eliminate ... More
Random Primordial Magnetic Fields and the Gas Content of Dark Matter HalosMay 04 2010Aug 24 2010We recently predicted the existence of random primordial magnetic fields (RPMF) in the form of randomly oriented cells with dipole-like structure with a cell size $L_0$ and an average magnetic field $B_0$. Here we investigate models for primordial magnetic ... More
Suppression of small baryonic structures due to a primordial magnetic fieldMar 14 2010We investigate the impact of the existence of a primordial magnetic field on the filter mass, characterizing the minimum baryonic mass that can form in dark matter (DM) haloes. For masses below the filter mass, the baryon content of DM haloes are severely ... More
Melting of a colloidal crystalMay 21 1997A melting transition for a system of hard spheres interacting by a repulsive Yukawa potential of DLVO form is studied. To find the location of the phase boundary, we propose a simple theory to calculate the free energies for the coexisting liquid and ... More
Continuity as a computational effectJul 12 2015Aug 01 2016The original purpose of component-based development was to provide techniques to master complex software, through composition, reuse and parametrisation. However, such systems are rapidly moving towards a level in which software becomes prevalently intertwined ... More
A Nonanticipative Analog Method for Long-Term Forecasting of Air Temperature ExtremesJul 12 2015A nonanticipative analog method is used for the long-term forecast of air temperature extremes. The data to be used for prediction include average daily air temperature, mean visibility, mean wind speed, mean dew point, maximum and minimum temperatures ... More
Asymmetric combination of logics is functorial: A surveyNov 13 2016May 08 2017Asymmetric combination of logics is a formal process that develops the characteristic features of a specific logic on top of another one. Typical examples include the development of temporal, hybrid, and probabilistic dimensions over a given base logic. ... More
Asymmetric combination of logics is functorialNov 13 2016Asymmetric combination of logics is a formal process that develops the characteristic features of a specific logic on top of another one. Typical examples include the development of temporal, hybrid, and probabilistic dimensions over a given base logic. ... More
A logic for n-dimensional hierarchical refinementJun 07 2016Hierarchical transition systems provide a popular mathematical structure to represent state-based software applications in which different layers of abstraction are represented by inter-related state machines. The decomposition of high level states into ... More
The role of logical interpretations in program developmentNov 27 2013Jan 29 2014Stepwise refinement of algebraic specifications is a well known formal methodology for program development. However, traditional notions of refinement based on signature morphisms are often too rigid to capture a number of relevant transformations in ... More
Refinement by interpretation in π-institutionsJun 21 2011The paper discusses the role of interpretations, understood as multifunctions that preserve and reflect logical consequence, as refinement witnesses in the general setting of pi-institutions. This leads to a smooth generalization of the refinement-by-interpretation ... More
Fundamentals for immediate implementation of a quantum secured InternetJul 14 2006Aug 16 2006This work shows how a secure Internet for users A and B can be implemented through a fast key distribution system that uses physical noise to encrypt information transmitted in deterministic form. Starting from a shared secret random sequence between ... More
A wireless secure key distribution system with no couriers: a One-Time-Pad RevivalJan 16 2019Among the problems to guarantee secrecy for in-transit information, the difficulties involved in renewing cryptographic keys in a secure way using couriers, the perfect secrecy encryption method known as One-Time-Pad (OTP) became almost obsolete. Pure ... More
Fast and secure key distribution using mesoscopic coherent states of lightDec 05 2002Apr 28 2004This work shows how two parties A and B can securely share sequences of random bits at optical speeds. A and B possess true-random physical sources and exchange random bits by using a random sequence received to cipher the following one to be sent. A ... More
Mixing angle and Glashow's AlgebraJul 20 2001Considering transformations in the basis of fundamental fields on a principal fiber bundle, without modification in the space-time sector, we construct an algebra GA, which we call Glashow algebra. The structure constants of this algebra depend on a mixing ... More
One-time pad booster for InternetApr 11 2007One-time pad encrypted files can be sent through Internet channels using current Internet protocols. However, the need for renewing shared secret keys make this method unpractical. This work shows how users can use a fast physical random generator based ... More
Transverse coincidence-structures in spontaneous parametric down-conversion with orbital angular momentum: TheoryJun 06 2007Coincidence-structures in the transverse plane of Type-II spontaneous parametric down-conversion carrying orbital angular momentum are obtained. Azimuthal symmetry breaking around the pump beam direction reveals itself on these quantum images. Analytical ... More
Noise Secured InternetOct 03 2005Feb 28 2006This work shows how a secure Internet can be implemented through a fast key distribution system that uses physical noise to protect the transmitted information. Starting from a shared random sequence $K_0$ between two (or more) users, longsequences $R$ ... More
Can humans see beyond intensity images?Feb 24 2012The human's visual system detect intensity images. Quite interesting, detector systems have shown the existence of different kind of images. Among them, images obtained by two detectors (detector array or spatially scanning detector) capturing signals ... More
A wireless physically secure key distribution systemJan 01 2016Jul 25 2016A secure key distribution protocol protected by light's noise was introduced in 2003 [Phys. Rev. A 68, 052307 (2003)]. That protocol utilized the shot noise of light present in the optical channel (eg., an optical fiber) to restrict information leaks ... More
Secure sharing of random bits over the InternetMay 15 2007May 17 2007Although one-time pad encrypted files can be sent through Internet channels, the need for renewing shared secret keys have made this method unpractical. This work presents a scheme to turn practical the fast sharing of random keys over arbitrary Internet ... More
The Effect of a Single Supernova Explosion on the Cuspy Density Profile of a Small-Mass Dark Matter HaloApr 14 2011Some observations of galaxies, and in particular dwarf galaxies, indicate a presence of cored density profiles in apparent contradiction with cusp profiles predicted by dark matter N-body simulations. We constructed an analytical model, using particle ... More
The rate of stellar encounters along a migrating orbit of the SunSep 28 2016The frequency of Galactic stellar encounters the Solar system experienced depends on the local density and velocity dispersion along the orbit of the Sun in the Milky Way galaxy. We aim at determining the effect of the radial migration of the solar orbit ... More
The Parker Instability in Disk GalaxiesOct 21 2015Nov 19 2015We examine the evolution of the Parker instability in galactic disks using 3D numerical simulations. We consider a local Cartesian box section of a galactic disk, where gas, magnetic fields and cosmic rays are all initially in a magnetohydrostatic equilibrium. ... More
The solar siblings in the Gaia eraFeb 04 2015We perform realistic simulations of the Sun's birth cluster in order to predict the current distribution of solar siblings in the Galaxy. We study the possibility of finding the solar siblings in the Gaia catalogue by using only positional and kinematic ... More
Backward Renormalization Priors and the Cortical Source Localization Problem with EEG or MEGFeb 11 2015We study source localization from high dimensional M/EEG data by extending a multiscale method based on Entropic inference devised to increase the spatial resolution of inverse problems. This method is used to construct informative prior distributions ... More
Radial Migration of the Sun in the Milky Way: a Statistical StudyOct 08 2014Oct 09 2014The determination of the birth radius of the Sun is important to understand the evolution and consequent disruption of the Sun's birth cluster in the Galaxy. Motivated by this fact, we study the motion of the Sun in the Milky Way during the last 4.6 Gyr ... More
Fluctuation Phenomena in Chaotic Dirac Quantum Dots: Artificial Atoms on Graphene FlakesOct 02 2015We develop the stub model for the Dirac Quantum Dot, an electron confining device on a grapheme surface. Analytical results for the average conductance and the correlation functions are obtained and found in agreement with those found previously using ... More
Yang-Mills fields as optical mediaJul 27 2001A geometrization of the Yang-Mills field, by which an SU(2) gauge theory becomes equivalent to a 3-space geometry - or optical system - is examined. In a first step, ambient space remains Euclidean and current problems on flat space can be looked at from ... More
Wu-Yang ambiguity in connection spaceOct 12 2004Two distinct gauge potentials can have the same field strength, in which case they are said to be ``copies'' of each other. The consequences of this possibility for the general space A of gauge potentials are examined. Any two potentials are connected ... More
Spin Accumulation Encoded in Electronic Noise for Mesoscopic Billiards with Finite Tunneling RatesAug 29 2011Apr 12 2012We study the effects of spin accumulation (inside reservoirs) on electronic transport with tunneling and reflections at the gates of a quantum dot. Within the stub model, the calculation focus on the current-current correlation function for the flux of ... More
Accretion Signatures from Massive Young Stellar ObjectsSep 08 2004High resolution (lambda / Delta-lambda = 50,000) K-band spectra of massive, embedded, young stellar objects are presented. The present sample consists of four massive young stars located in nascent clusters powering Galactic giant H II regions. Emission ... More
Tunable ${\cal χ/PT}$ Symmetry in Noisy GrapheneMay 23 2018We investigate the resonant regime of a mesoscopic cavity made of graphene or a doped beam splitter. Using Non-Hermitian Quantum Mechanics, we consider the Bender-Boettcher assumption that a system must obey parity and time reversal symmetry. Therefore, ... More
Anti-correlation for Conductance Fluctuations in Chaotic Quantum DotsJun 21 2013We investigate the correlation functions of mesoscopic electronic transport in open chaotic quantum dots with finite tunnel barriers in the crossover between Wigner-Dyson ensembles. Using an analytical stub formalism, we show the emergence of a depletion/amplification ... More
Chandra X-ray Observations of the Young Stellar Cluster NGC 6193 in the Ara OB1 AssociationApr 25 2005A 90 ks Chandra HETG observation of the young stellar cluster NGC 6193 in the southern Ara OB1 association detected 43 X-ray sources in a 2' x 2' core region centered on the young O stars HD 150135 (O6.5V) and HD 150136 (O3+O6V). The cluster is dominated ... More
Spectrophotometric Distances to Galactic H\,{\sc{ii}} RegionsSep 20 2010We present a near infrared study of the stellar content of 35 H\,{\sc{ii}} regions in the Galactic plane. In this work, we have used the near infrared domain $J-$, $H-$ and $K_{s}-$ band color images to visually inspect the sample. Also, color-color and ... More
A physical approach to modelling large-scale galactic magnetic fieldsSep 10 2018Jan 28 2019A convenient representation of the structure of the large-scale galactic magnetic field is required for the interpretation of polarization data in the sub-mm and radio ranges, in both the Milky Way and external galaxies. We develop a simple and flexible ... More
Conformal immersion of Riemannian products in low codimensionNov 13 2018We proved that a conformal immersion of $M_0^{n_0}\times M_1^{n_1}$ as an hipersurface in a Euclidean space must be an extrinsic product of immersions, under the assumption that $n_0, n_1 \geq 2$ and that $M^{n_0}_0\times M^{n_1}_1$ is not conformally ... More
Universal Spin Hall Conductance Fluctuations in Chaotic Dirac Quantum DotsMar 01 2016We present complete analytical and numerical results that demonstrate the anomalous universal fluctuations of the spin-Hall conductance in chiral materials such as graphene and topological insulators. We investigated both the corresponding fluctuations, ... More
High Spatial Resolution Spectroscopy of W51 IRS2E and IRS2W: Two Very Massive Young Stars in Early Formation StagesMar 27 2008We present $K$-band spectra of the near infrared counterparts to IRS2E and IRS2W which is associated with the ultracompact HII region W51d, both of them embedded sources in the Galactic compact HII region W51 IRS2. The high spatial resolution observations ... More
Enhanced flow of core-softened fluids through nanotubesJul 11 2013We investigate through non-equilibrium molecular dynamic simulations the flow of core-softened fluids inside nanotubes. Our results reveal a anomalous increase of the overall mass flux for nanotubes with sufficiently smaller radii. This is explained in ... More
Entanglement Distribution Statistic in Andreev BilliardsNov 02 2017We investigate statistical aspects of the entanglement production for open chaotic mesoscopic billiards in contact with superconducting parts, known as Andreev billiards. The complete distributions of concurrence and entanglement of formation are obtained ... More
Enlarged geometries of gauge bundlesJul 20 2001The geometrical picture of gauge theories must be enlarged when a gauge potential ceases to behave like a connection, as it does in electroweak interactions. When the gauge group has dimension four, the vector space isomorphism between spacetime and the ... More
Parity and Time Reversal Symmetry in Hanbury Brown-Twiss EffectFeb 15 2017The current manuscript employs the parity and time reversal symmetry in the Hanbury Brown-Twiss experiment. For this purpose, we develop a general scattering matrix framework founded on the concatenation of many individual compounded scattering processes ... More
Spacetime algebraic skeletonJul 10 2002Jul 10 2002The cosmological constant Lambda, which has seemingly dominated the primaeval Universe evolution and to which recent data attribute a significant present-time value, is shown to have an algebraic content: it is essentially an eigenvalue of a Casimir invariant ... More
Multiple liquid-liquid critical points and anomalies in core-softened potentialsJun 07 2012Jun 19 2012The relation between liquid-liquid phase transitions and waterlike density anomalies in core-softened potentials of fluids was investigated in an exactly solvable one dimensional lattice model and a in a three dimensional fluid with fermi-like potential, ... More
Quantum density anomaly in optically trapped ultracold gasesApr 24 2019We show that the Bose-Hubbard Model exhibits an increase in density with temperature at fixed pressure in the regular fluid regime and in the superfluid phase. The anomaly at the Bose-Einstein condensate is the first density anomaly observed in a quantum ... More
Quest for finding the lost siblings of the SunNov 21 2014The aim of this paper is to find lost siblings of the Sun by analyzing high resolution spectra. Finding solar siblings will enable us to constrain the parameters of the parental cluster and the birth place of the Sun in the Galaxy. The solar siblings ... More
Phase coherent resonator detection as a complete quantum measurement of the two-mode spectral quantum state of lightDec 18 2015The introduction of phase coherence in the detection of quantum noise of light yields a pure quantum measurement of spectral modes. We theoretically show that such coherent quantum measurement performed with the technique of resonator detection (RD) is ... More
Analyzing the Gaussian character of the spectral quantum state of light via quantum noise measurementsFeb 05 2015Gaussian quantum states hold special importance in the continuous variable (CV) regime. In quantum information science, the understanding and characterization of central resources such as entanglement may strongly rely on the knowledge of the Gaussian ... More
Experimental demonstration of three-color entanglementSep 22 2010Entanglement is the essential quantum resource for a potential speed-up of information processing, as well as for sophisticated quantum communication. Quantum information networks will be required to convey information from one place to another, by using ... More
Spin-to-Charge Conversion in 2D Electron Gas and Single-layer Graphene DevicesDec 13 2017We investigate the spin-to-charge conversion emerging from a mesoscopic device connected to multiple terminals. We obtain analytical expressions to the characteristic coefficient of spin-to-charge conversion which are applied in two kinds of ballistic ... More
Presence of asymmetric noise in multi-terminal chaotic cavitiesAug 24 2011This work deals with chaotic quantum dot connected to two and four leads. We use standard diagrammatic procedure to integrate on the unitary group, to study the main term in the semiclassical expansion of the noise in the three pure Wigner-Dyson ensembles ... More
Anomalous Entanglement in Chaotic Dirac BilliardsJan 22 2015We present analytical and numerical results that demonstrate the presence of anomalous entanglement behavior on the Dirac Billiards. We investigate the statistical distribution of the characteristic entangled measures, focusing on the mean, on the variance ... More
A generalized Bak-Sneppen model for Earth's magnetic field reversalsJun 24 2011We introduce a simple model for Earth's magnetic field reversals. The model consists in random nodes simulating vortices in the liquid part of the core which through a simple updating algorithm converge to a self organized critical state, with inter-reversal ... More
Crossover of thermal to shot noise in chaotic cavitiesFeb 21 2011We study the crossover between thermal and shot-noise power in a chaotic quantum dot in the presence of non-ideal contacts at finite temperature. The result explicitly demonstrates that the temperature affect the suppression-amplification effect present ... More
The Stellar Content of Obscured Galactic Giant HII Regions. VI: W51AFeb 25 2008We present K-band spectra of newly born OB stars in the obscured Galactic giant H II region W51A and ~ 0.8'' angular resolution images in the J, H and K_S-bands. Four objects have been spectroscopically classified as O-type stars. The mean spectroscopic ... More
Conductance Peak Density in NanowiresSep 22 2018We present a complete numerical calculation and an experimental data analysis of the universal conductance fluctuations in quasi-one-dimension nanowires. The conductance peak density model, introduced in nanodevice research on [Phys. Rev. Lett. 107, 176807 ... More
Universal Braess paradox in open quantum dotsOct 28 2014We present analytical and numerical results that demonstrate the presence of the Braess paradox in chaotic quantum dots. The paradox that we identify, originally perceived in classical networks, shows that the addition of more capacity to the network ... More
Gemini Mid-Infrared Imaging of Massive Young Stellar Objects in NGC 3576Aug 11 2003We present a mid-infrared study of NGC 3576. The high-resolution images were taken at the Gemini South Observatory through narrow and broad band filters centered between 7.9 micron and 18 micron. The nearly diffraction limited images show IRS 1 resolved ... More
The statistics of chaos in a bursting laserFeb 07 2019We demonstrate experimentally how semiconductor lasers subjected to double optical feedback change the statistics of their chaotic spiking dynamics from Gaussian to long-tail Power Law distributions associated to the emergency of bursting. These chaotic ... More
Modeling the input history of programs for improved instruction-memory performanceNov 23 2004When a program is loaded into memory for execution, the relative position of its basic blocks is crucial, since loading basic blocks that are unlikely to be executed first places them high in the instruction-memory hierarchy only to be dislodged as the ... More
Time-Reversal Symmetry Breaking and Decoherence in Chaotic Dirac BilliardsSep 21 2016In this work, we perform a statistical study on Dirac Billiards in the extreme quantum limit (a single open channel on the leads). Our numerical analysis uses a large ensemble of random matrices and demonstrates the preponderant role of dephasing mechanisms ... More
Generalized correlation functions for conductance fluctuations and the mesoscopic spin Hall effectDec 09 2012We study the spin-Hall conductance fluctuations in ballistic mesoscopic systems. We obtain universal expressions for the spin and charge current fluctuations, cast in terms of current-current autocorrelation functions. We show that the latter are conveniently ... More
The Lower Bound Error for polynomial NARMAX using an Arbitrary Number of Natural Interval ExtensionsNov 21 2017The polynomial NARMAX (Nonlinear AutoRegressive Moving Average model with eXogenous input) is a model that represents the dynamics of physical systems. This polynomial contains information from the past of the inputs and outputs of the process, that is, ... More
Molecular correlations and solvation in simple fluidsMar 11 2010We study the molecular correlations in a lattice model of a solution of a low-solubility solute, with emphasis on how the thermodynamics is reflected in the correlation functions. The model is treated in Bethe-Guggenheim approximation, which is exact ... More
Properties of magnetic nanodots with perpendicular anisotropyMay 09 2011Nanodots with magnetic vortices have many potential applications, such as magnetic memories (VRAMs) and spin transfer nano-oscillators (STNOs). Adding a perpendicular anisotropy term to the magnetic energy of the nanodot it becomes possible to tune the ... More
Correlation functions and correlation widths in Quantum-Chaotic Scattering for mesoscopic systems and nucleiAug 05 2015Oct 07 2015We derive analytical expressions for the correlation functions of the electronic conductance fluctuations of an open quantum dot under several conditions. Both the variation of energy and that of an external parameter such as an applied perpendicular ... More
Minimal chordal sense of direction and circulant graphsMar 03 2005A sense of direction is an edge labeling on graphs that follows a globally consistent scheme and is known to considerably reduce the complexity of several distributed problems. In this paper, we study a particular instance of sense of direction, called ... More
On the mediation of program allocation in high-demand environmentsApr 27 2016Apr 28 2016In this paper we challenge the widely accepted premise that, in order to carry out a distributed computation, say on the cloud, users have to inform, along with all the inputs that the algorithm in use requires, the number of processors to be used. We ... More
The evolution of the Sun's birth cluster and the search for the solar siblings with GaiaJan 04 2016We use self-consistent numerical simulations of the evolution and disruption of the Sun's birth cluster in the Milky Way potential to investigate the present-day phase space distribution of the Sun's siblings. The simulations include the gravitational ... More
Robustness of bipartite Gaussian entangled beams propagating in lossy channelsSep 22 2010Subtle quantum properties offer exciting new prospects in optical communications. Quantum entanglement enables the secure exchange of cryptographic keys and the distribution of quantum information by teleportation. Entangled bright beams of light attract ... More
Improving the Global Fitting Method on Non-Linear Time Series AnalysisMay 09 2006In this paper, we are concerned with improving the forecast capabilities of the Global approach to Time Series. We assume that the normal techniques of Global mapping are applied, the noise reduction is performed, etc. Then, using the mathematical foundations ... More
Untappable key distribution system: a one-time-pad boosterJun 05 2014Jul 08 2015One-time-pad (OTP) encryption simply cannot be cracked, even by a quantum computer. The need of sharing in a secure way supplies of symmetric random keys turned the method almost obsolete as a standing-alone method for fast and large volume telecommunication. ... More
Is the Sgr dSph a dark matter dominated system?Sep 05 2012We study the evolution of possible progenitors of Sgr dSph}using several numerical N-body simulations of different dwarf spheroidal galaxies both with and without dark matter, as they orbit the Milky Way. The barionic and dark components of the dwarfs ... More
6-cycle double covers of cubic graphsMay 31 2005Apr 17 2009A cycle double cover (CDC) of an undirected graph is a collection of the graph's cycles such that every edge of the graph belongs to exactly two cycles. We describe a constructive method for generating all the cubic graphs that have a 6-CDC (a CDC in ... More
Approximate conditional distributions of distances between nodes in a two-dimensional sensor networkDec 17 2008When we represent a network of sensors in Euclidean space by a graph, there are two distances between any two nodes that we may consider. One of them is the Euclidean distance. The other is the distance between the two nodes in the graph, defined to be ... More
Charge reversal of colloidal particlesSep 23 2005A theory is presented for the effective charge of colloidal particles in suspensions containing multivalent counterions. It is shown that if colloids are sufficiently strongly charged, the number of condensed multivalent counterion can exceed the bare ... More
Flexible Polyelectrolytes with Monovalent SaltJul 23 2004We present a model for describing flexible polyelectrolytes in a good solvent a nd in the presence of monovalent salt . The molecule composed by $N$ monomers is characterized by the end to end distanc e $R_e=b (Z-1)^\gamma$ and the number of associated ... More
New Territory: SZ Cluster SurveysAug 27 1998The potential of the Sunyaev-Zel'dovich (SZ) effect for cluster studies has long been appreciated, although not yet fully exploited. Recent technological advances and improvements in observing strategies have changed this, to the point where it is now ... More
Multiple sequence alignment based on set coversDec 10 2004We introduce a new heuristic for the multiple alignment of a set of sequences. The heuristic is based on a set cover of the residue alphabet of the sequences, and also on the determination of a significant set of blocks comprising subsequences of the ... More
Finding approximate palindromes in stringsSep 23 2003We introduce a novel definition of approximate palindromes in strings, and provide an algorithm to find all maximal approximate palindromes in a string with up to $k$ errors. Our definition is based on the usual edit operations of approximate pattern ... More
Counting independent terms in big-oh notationDec 31 2015The field of computational complexity is concerned both with the intrinsic hardness of computational problems and with the efficiency of algorithms to solve them. Given such a problem, normally one designs an algorithm to solve it and sets about establishing ... More
Disentanglement in Bipartite Continuous-Variable SystemsSep 22 2010Nov 17 2011Entanglement in bipartite continuous-variable systems is investigated in the presence of partial losses, such as those introduced by a realistic quantum communication channel, e.g. by propagation in an optical fiber. We find that entanglement can vanish ... More