Results for "Sebastián A. Franchino-Viñas"

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Worldline Formalism and Noncommutative TheoriesOct 05 2015The objective of this Ph.D. thesis is the implementation of the Worldline Formalism in the frame of Noncommutative Quantum Field Theories. The result is a master formula for the 1-loop effective action that is applied to a number of scalar models -- among ... More
Vacuum effective actions and mass-dependent renormalization in curved spaceFeb 08 2019We review past and present results on the non-local form-factors of the effective action of semiclassical gravity in two and four dimensions computed by means of a covariant expansion of the heat kernel up to the second order in the curvatures. We discuss ... More
Worldline approach to the Grosse-Wulkenhaar modelJun 28 2014Dec 05 2014We apply the worldline formalism to the Grosse-Wulkenhaar model and obtain an expression for the one-loop effective action which provides an efficient way for computing Schwinger functions in this theory. Using this expression we obtain the quantum corrections ... More
Pumping current of a Luttinger liquid with finite lengthMar 16 2012We study transport properties in a Tomonaga-Luttinger liquid in the presence of two time-dependent point like weak impurities, taking into account finite-length effects. By employing analytical methods and performing a perturbation theory, we compute ... More
Form factors and decoupling of matter fields in four-dimensional gravityDec 02 2018Jan 31 2019We extend previous calculations of the non-local form factors of semiclassical gravity in $4D$ to include the Einstein-Hilbert term. The quantized fields are massive scalar, fermion and vector fields. The non-local form factor in this case can be seen ... More
The Interaction Between PDE and Graphs in Multiscale ModelingMay 27 2015Apr 18 2016In this article an upscaled model is presented, for complex networks with highly clustered regions exchanging some abstract quantities in both, microscale and macroscale level. Such an intricate system is approximated by a partitioned open map in $\mathbb{R}^{2}$ ... More
Gas electron multiplier based on laser-perforated CVD diamond film: First testsJun 18 2016Gas electron multiplier (GEM) is widely used in modern gas detectors of ionizing radiation in experiments on high-energy physics at accelerators and in other fields of science. Typically the GEM devices are based on a dielectric foil with holes and electrodes ... More
Discriminative training for Convolved Multiple-Output Gaussian processesFeb 07 2015Multi-output Gaussian processes (MOGP) are probability distributions over vector-valued functions, and have been previously used for multi-output regression and for multi-class classification. A less explored facet of the multi-output Gaussian process ... More
Semi-transparent Boundary Conditions in the Worldline FormalismDec 13 2010The interaction of a quantum field with a background containing a Dirac delta function with support on a surface of codimension 1 represents a particular kind of matching conditions on that surface for the field. In this article we show that the worldline ... More
Expansion-Free Cavity Evolution: Some exact Analytical ModelsMar 18 2011Nov 29 2011We consider spherically symmetric distributions of anisotropic fluids with a central vacuum cavity, evolving under the condition of vanishing expansion scalar. Some analytical solutions are found satisfying Darmois junction conditions on both delimiting ... More
Magnetic properties of a Fermi gas in a noncommutative phase spaceJun 10 2016Motivated by the precision attained by SQUID devices in measuring magnetic fields, we study in this article the thermodynamic behaviour of a fermion gas in two and three dimen\-sional spatial space with noncommutative coordinates and momenta. An explicit ... More
Boundaries in the Moyal planeJul 17 2013Dec 20 2013We study the oscillations of a scalar field on a noncommutative disc implementing the boundary as the limit case of an interaction with an appropriately chosen confining background. The space of quantum fluctuations of the field is finite dimensional ... More
Worldline approach to noncommutative field theoryApr 04 2012Jan 25 2013The study of the heat-trace expansion in noncommutative field theory has shown the existence of Moyal nonlocal Seeley-DeWitt coefficients which are related to the UV/IR mixing and manifest, in some cases, the non-renormalizability of the theory. We show ... More
Dynamical cubes and a criteria for systems having products extensionsJun 04 2014For minimal $\mathbb{Z}^{2}$-topological dynamical systems, we introduce a cube structure and a variation of the regionally proximal relation for $\mathbb{Z}^2$ actions, which allow us to characterize product systems and their factors. We also introduce ... More
On Riemann surfaces of genus $g$ with $4g-4$ automorphismsDec 03 2018In this article we study compact Riemann surfaces with a non-large group of automorphisms of maximal order; namely, compact Riemann surfaces of genus $g$ with a group of automorphisms of order $4g-4.$ Under the assumption that $g-1$ is prime, we provide ... More
Galois subspaces for the rational normal curveSep 07 2018We characterize all $(n-2)$-dimensional linear subspaces of $\mathbb{P}^{n}$ such that the induced linear projection, when restricted to the rational normal curve, gives a Galois morphism. We give an explicit description of these spaces as a disjoint ... More
A branch and cut algorithm for minimum spanning trees under conflict constraintsJul 04 2013Jun 30 2014We study approaches for the exact solution of the \NP--hard minimum spanning tree problem under conflict constraints. Given a graph $G(V,E)$ and a set $C \subset E \times E$ of conflicting edge pairs, the problem consists of finding a conflict-free minimum ... More
A Production Oriented Approach for Vandalism Detection in Wikidata - The Buffaloberry Vandalism Detector at WSDM Cup 2017Dec 19 2017Wikidata is a free and open knowledge base from the Wikimedia Foundation, that not only acts as a central storage of structured data for other projects of the organization, but also for a growing array of information systems, including search engines. ... More
A hierarchy of topological systems with completely positive entropyMar 05 2018Aug 27 2018We define a hierarchy of systems with topological completely positive entropy in the context of continuous countable amenable group actions on compact metric spaces. For each countable ordinal we construct a dynamical system on the corresponding level ... More
A Consciousness-Based Quantum Objective Collapse ModelJan 16 2018Jul 23 2018Ever since the early days of quantum mechanics it has been suggested that consciousness could be linked to the collapse of the wave function. However, no detailed account of such an interplay is usually provided. In this paper we present an objective ... More
A generalisation of Kani-Rosen decomposition theorem for Jacobian varietiesFeb 01 2017Dec 07 2017In this short paper we generalise a theorem due to Kani and Rosen on decomposition of Jacobian varieties of Riemann surfaces with group action. This generalisation extends the set of Jacobians for which it is possible to obtain an isogeny decomposition ... More
Families of Riemann Surfaces, Uniformization and ArithmeticityOct 13 2015Apr 05 2016A consequence of the results of Bers and Griffiths on the uniformization of complex algebraic varieties is that the universal cover of a family of Riemann surfaces, with base and fibers of finite hyperbolic type, is a contractible 2-dimensional domain ... More
Directional dynamical cubes for minimal $\mathbb{Z}^{d}$-systemsSep 25 2018We introduce the notions of directional dynamical cubes and directional regionally proximal relation defined via these cubes for a minimal $\mathbb{Z}^d$-system $(X,T_1,\ldots,T_d)$. We study the structural properties of systems that satisfy the so called ... More
The Data Analysis Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey: Emission-Line ModelingJan 03 2019Jan 11 2019SDSS-IV MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) is the largest integral-field spectroscopy survey to date, aiming to observe a statistically representative sample of 10,000 low-redshift galaxies. In this paper we study the reliability ... More
Reconstruction of a kinetic k--essence Lagrangian from a modified of dark energy equation of stateApr 08 2018In this paper the Lagrangian density of a purely kinetic k--essence that models the behavior of dark energy described by four parameterized equations of state proposed by Cooray \& Huterer (Astrophys. J. {\bf 513} L95, 1999), Zhang \& Wu (Mod. Phys. Lett. ... More
On the structure of (claw,bull)-free graphsDec 31 2018In this research, we determine the structure of (claw, bull)-free graphs. We show that every connected (claw, bull)-free graph is either an expansion of a path, an expansion of a cycle, or the complement of a triangle-free graph; where an expansion of ... More
Determination of polariton condensates' critical temperatureFeb 12 2019We investigate the thermal robustness of traveling polariton condensates. We create remote condensates that have never been in contact, and study their interference in momentum space, when they travel with the same velocity, by means of time-resolved ... More
Differential Galois theory and isomonodromic deformationsOct 19 2018Here we present a geometric setting for the differential Galois theory of $G$-invariant connections with parameters. As an application of some classical results on differential algebraic groups and Lie algebra bundles, we see that the Galois group with ... More
Poisson and symplectic reductions of 4-DOF isotropic oscillators. The van der Waals system as benchmarkFeb 07 2015This paper is devoted to studying Hamiltonian oscillators in 1:1:1:1 resonance with symmetries, which include several models of perturbed Keplerian systems. Normal forms are computed in Poisson and symplectic formalisms, by mean of invariants and Lie-transforms ... More
On automorphism groups of Toeplitz subshiftsJan 04 2017Jun 14 2017In this article we study automorphisms of Toeplitz subshifts. Such groups are abelian and any finitely generated torsion subgroup is finite and cyclic. When the complexity is non superlinear, we prove that the automorphism group is, modulo a finite cyclic ... More
Temperature dependence of the coherence in polariton condensatesOct 17 2017Feb 28 2018We present a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates. The simultaneous detection of their emission both in real- and reciprocal-space allows us to fully monitor the condensates' dynamics. ... More
The inverse problem of the calculus of variations for discrete systemsAug 14 2017We develop a geometric version of the inverse problem of the calculus of variations for discrete mechanics and constrained discrete mechanics. The geometric approach consists of using suitable Lagrangian and isotropic submanifolds. We also provide a transition ... More
Retrieving intracycle interference in angular-resolved laser-assisted photoemission from argonAug 14 2018We report on a combined experimental and theoretical study of XUV ionization of atomic argon in the presence of a near-infrared laser field. The resulting energy- and angle- resolved photoemission spectra have been described in the literature as interferences ... More
The Data Analysis Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey: OverviewJan 03 2019Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is acquiring integral-field spectroscopy for the largest sample of galaxies to date. By 2020, the MaNGA Survey --- one of three core programs in the fourth-generation Sloan Digital Sky Survey ... More
Cooperative behavior of molecular motions giving rise to two glass transitions in the same supercooled mesophase of a smectogenic odd liquid crystal dimerOct 01 2018In the present work, a detailed analysis of the glassy behavior and the relaxation dynamics of the liquid crystal dimer {\alpha}-(4-cyanobiphenyl-4'-yloxy)-{\omega}-(1-pyrenimine-benzylidene-4'-oxy) heptane (CBO7O.Py) throughout both nematic and smectic ... More
Revival of an abandoned telescope: the Boller and Chivens Bochum 0.61-metre telescope of Universidad de ValparaisoAug 10 2018In 2015 the Institute of Physics and Astronomy of the Universidad de Valpara\'iso in Chile received as a donation the Bochum 0.61-meter telescope. Here we preset the ongoing project to convert this senior member of La Silla Observatory to modern standards ... More
Geometric and physical properties of closed ever expanding dust modelsApr 18 2018Current observations suggest that our Universe is not incompatible with a small positive spatial curvature that can be associated with rest frames having a "closed" standard topology. We examine a toy model generalisation of the $\Lambda$CDM model in ... More
Serendipitous discovery of a strong-lensed galaxy in integral field spectroscopy from MUSEMar 25 2018May 31 20182MASX J04035024-0239275 is a bright red elliptical galaxy at redshift 0.0661 that presents two extended sources at 2\arcsec~to the north-east and 1\arcsec~to the south-west. The sizes and surface brightnesses of the two blue sources are consistent with ... More
Dust unveils the formation of a mini-Neptune planet in a protoplanetary ringFeb 13 2019Rings and radial gaps are ubiquitous in protoplanetary disks. Their possible connection to planet formation is currently subject to intense debate. In principle, giant planet formation leads to wide gaps which separate the gas and dust mass reservoir ... More
Relative drifts and temperature anisotropies of protons and $α$ particles in the expanding solar wind -- 2.5D hybrid simulationsOct 10 2014We perform 2.5D hybrid simulations to investigate the origin and evolution of relative drift speeds between protons and $\alpha$ particles in the collisionless turbulent low-$\beta$ solar wind plasma. We study the generation of differential streaming ... More
Equilibrium states for a class of skew-productsAug 06 2018We consider skew-products on $M\times \mathbb{T}^2$, where $M$ is the two-sphere or the two-torus, which are partially hyperbolic and semi-conjugate to an Axiom A diffeomorphism. This class of dynamics includes the open sets of $\Omega$-non-stable systems ... More
A formula for the local metric pressureJan 22 2019In this note we present a formula for the local metric pressure that generalizes Brin-Katok result for the metric entropy. As an application, we give a straightforward proof of the fact that non-atomic weak-Gibbs invariant probability measures are equilibrium ... More
Ion Heating in Inhomogeneous Expanding Solar Wind Plasma: The Role of Parallel and Oblique Ion-Cyclotron WavesJul 17 2014Sep 30 2014Remote sensing observations of coronal holes show that heavy ions are hotter than protons and their temperature is anisotropic. In-situ observations of fast solar wind streams provide direct evidence for turbulent Alfv\'en wave spectrum, left-hand polarized ... More
GW150914: First search for the electromagnetic counterpart of a gravitational-wave event by the TOROS collaborationJul 26 2016We present the results of the optical follow-up conducted by the TOROS collaboration of the first gravitational-wave event GW150914. We conducted unfiltered CCD observations (0.35-1 micron) with the 1.5-m telescope at Bosque Alegre starting ~2.5 days ... More
Beam shaping for laser-based adaptive optics in astronomyMay 21 2014The availability and performance of laser-based adaptive optics (AO) systems are strongly dependent on the power and quality of the laser beam before being projected to the sky. Frequent and time-consuming alignment procedures are usually required in ... More
Measurement of the muon inclusive cross section in pp collisions at $\sqrt{s}$ = 7 TeV with the ATLAS detectorNov 21 2011The measurement of the muon inclusive di?fferential cross section dsigma/dpT in pp collisions at sqrt(s)=7 TeV with the ATLAS detector is presented. The analysis is performed in the pseudorapidity interval |eta|< 2.5 for muon of transverse momentum 4 ... More
Energy relaxation of exciton-polariton condensates in quasi-1D microcavitiesApr 09 2013Jul 12 2013We present a time-resolved study of energy relaxation and trapping dynamics of polariton condensates in a semiconductor microcavity ridge. The combination of two non-resonant, pulsed laser sources in a GaAs ridge-shaped microcavity gives rise to profuse ... More
Spin Selective Filtering of Polariton Condensate FlowApr 08 2015Spin-selective spatial filtering of propagating polariton condensates, using a controllable spin-dependent gating barrier, in a one-dimensional semiconductor microcavity ridge waveguide is reported. A nonresonant laser beam provides the source of propagating ... More
Model dependence of the neutron-skin thickness on the symmetry energyMay 17 2016The model dependence in the correlations of the neutron-skin thickness in heavy nuclei with various symmetry energy parameters is analyzed by using several families of systematically varied microscopic mean field models. Such correlations show a varying ... More
Non-equilibrium properties of graphene probed by superconducting tunnel spectroscopyNov 21 2018Feb 14 2019We report on non-equilibrium properties of graphene probed by superconducting tunnel spectroscopy. A hexagonal boron nitride (hBN) tunnel barrier in combination with a superconducting Pb contact is used to extract the local energy distribution function ... More
Blender-horseshoes in center-unstable Hénon-like familiesApr 07 2018A blender-horseshoe is a locally maximal transitive hyperbolic set that appears in dimension at least three carrying a distinctive geometrical property: its local stable manifold "behaves" as a manifold of topological dimension greater than the expected ... More
A Categorical Generalization of CounterpointSep 30 2018We extend Mazzola's counterpoint model in terms of category theory. One immediate outcome is the possibility of relaxing the "yes/no" character of the definitions of consonance, and stressing its dependence on context in general. A counterpoint model ... More
Fields of moduli of classical Humbert curvesSep 16 2016The computation of the field of moduli of a closed Riemann surface seems to be a very difficult problem and even more difficult is to determine if the field of moduli is a field of definition. In this paper we consider the family of closed Riemann surfaces ... More
Inversion of nonsmooth maps between Banach spacesDec 02 2017May 15 2018We study the invertibility nonsmooth maps between infinite-dimensional Banach spaces. To this end, we introduce an analogue of the notion of pseudo-Jacobian matrix of Jeyakumar and Luc in this infinite-dimensional setting. Using this, we obtain several ... More
Counter-directional polariton couplerFeb 11 2019We report on an on-chip routing device for propagating condensates of exciton-polaritons. This counterdirectional coupler implements signal control by a photonic microdisk potential, which couples two lithographically defined waveguides and reverses the ... More
The Three Hundred project: a large catalogue of theoretically modelled galaxy clusters for cosmological and astrophysical applicationsSep 12 2018We introduce the THE THREE HUNDRED project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the data set and study the differences to observations for fundamental galaxy cluster properties ... More
The Origin of the Entropy in the UniverseOct 15 1996Mar 13 1997We discuss the entropy generation in quantum tunneling of a relativistic particle under the influence of a time varying force with the help of squeezing formalism. It is shown that if one associates classical coarse grained entropy to the phase space ... More
Controlling skyrmion helicity via engineered Dzyaloshinskii-Moriya interactionsNov 14 2015Single magnetic skyrmion dynamics in chiral magnets with a spatially inhomogeneous Dzyaloshinskii-Moriya interaction (DMI) is considered. Based on the relation between DMI coupling and skyrmion helicity, it is argued that the latter must be included as ... More
Hénon-like families and blender-horseshoes at non-transverse heterodimensional cyclesJun 17 2018In dimension three and under certain regularity assumptions, we construct a renormalisation scheme at the heterodimensional tangency of a non-transverse heterodimensional cycle associated with a pair of saddle-foci whose limit dynamic is a center-unstable ... More
Particle Creation in the Bell-Szekeres SpacetimeNov 24 1995The quantization of a real massless scalar field in a spacetime produced in a collision of two electromagnetic plane waves with constant wave fronts is considered. The background geometry in the interaction region, the Bell-Szekeres solution, is locally ... More
Bi-Directional Energy Cascades and the Origin of Kinetic Alfvénic and Whistler Turbulence in the Solar WindJul 09 2013Jan 01 2014The observed sub-proton scale turbulence spectrum in the solar wind raises the question of how that turbulence originates. Observations of keV energetic electrons during solar quite-time suggest them as possible source of free energy to drive the turbulence. ... More
Pairing correlations of cold fermionic gases at overflow from a narrow to a wide harmonic trapSep 17 2014Nov 05 2014Within the context of Hartree-Fock-Bogoliubov theory, we study the behavior of superfluid Fermi systems when they pass from a small to a large container. Such systems can be now realized thanks to recent progress in experimental techniques. It will allow ... More
Pairing in exotic neutron rich nuclei around the drip line and in the crust of neutron starsMar 22 2013Exotic and drip-line nuclei as well as nuclei immersed in a low density gas of neutrons in the outer crust of neutron stars are systematically investigated with respect to their neutron pairing properties. This is done using Skyrme density-functional ... More
Exploring the Kibble-Zurek mechanism in a secondary bifurcationMar 08 2011We present new experimental results on the quenching dynamics of an extended thermo-convective system (a network array of approximately 100 convective oscillators) going through a secondary subcritical bifurcation. We characterize a dynamical phase transition ... More
Microscopic-Macroscopic Approach for Binding Energies with the Wigner-Kirkwood Method - IIJul 02 2012The binding energies of deformed even-even nuclei have been analysed within the framework of a recently proposed microscopic-macroscopic model. We have used the semiclassical Wigner - Kirkwood $\hbar$ expansion up to fourth - order, instead of the usual ... More
An effective decomposition approach and heuristics to generate spanning trees with a small number of branch verticesSep 22 2015Jun 30 2016Given a graph $G=(V,E)$, the minimum branch vertices problem consists in finding a spanning tree $T=(V,E')$ of $G$ minimizing the number of vertices with degree greater than two. We consider a simple combinatorial lower bound for the problem, from which ... More
Microscopic-Macroscopic Approach for Binding Energies with Wigner-Kirkwood MethodNov 24 2009The semi-classical Wigner-Kirkwood $\hbar$ expansion method is used to calculate shell corrections for spherical and deformed nuclei. The expansion is carried out up to fourth order in $\hbar$. A systematic study of Wigner-Kirkwood averaged energies is ... More
Action Integrals and discrete seriesAug 08 2011Let $G$ be a complex semisimple Lie group and ${G}_{\mathbb R}$ a real form that contains a compact Cartan subgroup $T_{\mathbb R}$. Let $\pi$ be a discrete series representation of $G_{\mathbb R}$. We present geometric interpretations in terms of concepts ... More
Invariants under deformation of the actions of topological groupsMay 20 2016Let $\varphi$ and $\varphi'$ be two homotopic actions of the topological group $G$ on the topological space $X$. To an object $A$ in the $G$-equivariant derived category $D_{\varphi}(X)$ of $X$ relative to the action $\varphi$ we associate an object $A'$ ... More
A Characteristic Number of Hamiltonian Bundles over $S^2$Jun 09 2005Dec 16 2005Each loop $\psi$ in the group $\text{Ham}(M)$ of Hamiltonian diffeomorphisms of a symplectic manifold $M$ determines a fibration $E$ on $S^2$, whose coupling class \cite{G-L-S} is denoted by $c$. If $VTE$ is the vertical tangent bundle of $E$, we relate ... More
Continuous families of Hamiltonian torus actionsMay 19 2008We determine conditions under which two Hamiltonian torus actions on a symplectic manifold $M$ are homotopic by a family of Hamiltonian torus actions, when $M$ is a toric manifold and when $M$ is a coadjoint orbit.
Charge of $D$-branes on singular varietiesNov 19 2018Considering the $D$-branes on a variety $Z$ as the objects of the derived category $D^b(Z)$, we propose a definition for the charge of $D$-branes on not necessarily smooth varieties. We define the charge $Q({\mathcal G})$ of ${\mathcal G}\in D^b(Z)$ as ... More
Lifting Hamiltonian loops to isotopies in fibrationsFeb 22 2013Let $G$ be a Lie group, $H$ a closed subgroup and $M$ the homogeneous space $G/H$. Each representation $\Psi$ of $H$ determines a $G$-equivariant principal bundle ${\mathcal P}$ on $M$ endowed with a $G$-invariant connection. We consider subgroups ${\mathcal ... More
The stellar metallicity gradients in galaxy discs in a cosmological scenarioApr 27 2016The stellar metallicity gradients of disc galaxies provide information on the disc assembly, star formation processes and chemical evolution. They also might store information on dynamical processes which could affect the distribution of chemical elements ... More
All-carbon multi-electrode array for real-time in vitro measurements of oxidizable neurotransmittersAug 25 2016We report on the ion beam fabrication of all-carbon multi electrode arrays (MEAs) based on 16 graphitic micro-channels embedded in single-crystal diamond (SCD) substrates. The fabricated SCD-MEAs are systematically employed for the in vitro simultaneous ... More
Cohomological vertex operatorsJul 26 2016Given a Calabi-Yau manifold and considering the $B$-branes on it as objects in the derived category of coherent sheaves, we identify the vertex operators for strings between two branes with elements of the cohomology groups of Ext sheaves. We define the ... More
Spanning Class in the Category of BranesApr 11 2018Given a generic anticanonical hypersurface $Y$ of a toric variety determined by a reflexive polytope, we define a line bundle ${\mathcal L}$ on $Y$ that generates a spanning class in the bounded derivative category $D^b(Y)$. From this fact, we deduce ... More
Equivariant branesFeb 06 2015Feb 10 2015Given a Calabi-Yau manifold $X$ acted by a group $G$ and considering the $B$-branes on $X$ as objects in the derived category of coherent sheaves, we give a definition of equivariant branes, which generalizes the concept of equivariant sheaves. We also ... More
A characteristic number of bundles determined by mass linear pairsSep 09 2008Nov 13 2008Let $\Delta$ be a Delzant polytope in ${\mathbb R}^n$ and ${\bf b}\in{\mathbb Z}^n$. Let $E$ denote the symplectic fibration over $S^2$ determined by the pair $(\Delta, {\bf b})$. We prove the equivalence between the fact that $(\Delta, {\bf b})$ is a ... More
Critical values of moment maps on quantizable manifoldsNov 02 2007Let $M$ be a quantizable symplectic manifold acted on by $T=(S^1)^r$ in a Hamiltonian fashion and $J$ a moment map for this action. Suppose that the set $M^{T}$ of fixed points is discrete and denote by ${\alpha}_{pj}\in{\mathbb Z}^r$ the weights of the ... More
Action integrals and infinitesimal charactersAug 14 2008Oct 26 2009Let $G$ be a reductive Lie group and ${\mathcal O}$ the coadjoint orbit of a hyperbolic element of ${\frak g}^*$. By $\pi$ is denoted the unitary irreducible representation of $G$ associated with ${\mathcal O}$ by the orbit method. We give geometric interpretations ... More
Characteristic number associated to mass linear pairsJun 15 2011Aug 09 2011Let $\Delta$ be a Delzant polytope in ${\mathbb R}^n$ and ${\mathbf b}\in{\mathbb Z}^n$. Let $E$ denote the symplectic fibration over $S^2$ determined by the pair $(\Delta,\,{\mathbf b})$. Under certain hypotheses, we prove the equivalence between the ... More
Hamiltonian diffeomorphisms of toric manifoldsJun 09 2005We prove that $\pi_1(\text{Ham}(M))$ contains an infinite cyclic subgroup, where $\text{Ham}(M)$ is the Hamiltonian group of the one point blow up of ${\Bbb C}P^3$. We give a sufficient condition for the group $\pi_1(\text{Ham}(M))$ to contain an infinite ... More
Cohomological vertex operatorsJul 26 2016Jan 12 2017Given a Calabi-Yau manifold and considering the $B$-branes on it as objects in the derived category of coherent sheaves, we identify the vertex operators for strings between two branes with elements of the cohomology groups of Ext sheaves. We define the ... More
Creation and analysis of biochemical constraint-based models: the COBRA Toolbox v3.0Oct 11 2017Feb 23 2018COnstraint-Based Reconstruction and Analysis (COBRA) provides a molecular mechanistic framework for integrative analysis of experimental data and quantitative prediction of physicochemically and biochemically feasible phenotypic states. The COBRA Toolbox ... More
Structural and Dynamical Patterns on Online Social Networks: the Spanish May 15th Movement as a case studyJul 08 2011The number of people using online social networks in their everyday life is continuously growing at a pace never saw before. This new kind of communication has an enormous impact on opinions, cultural trends, information spreading and even in the commercial ... More
Enveloping semigroups of systems of order dMay 07 2013In this paper we study the Ellis semigroup of a d-step nilsystem and the inverse limit of such systems. By using the machinery of cubes developed by Host, Kra and Maass, we prove that such a system has a d-step topologically nilpotent enveloping semigroup. ... More
NPF: mirror development in ChileJul 17 2018Jul 19 2018In the era of high-angular resolution astronomical instrumentation, where long and very long baseline interferometers (constituted by many, $\sim$ 20 or more, telescopes) are expected to work not only in the millimeter and submillimeter domain, but also ... More
Quasiplatonic curves with symmetry group ${\mathbb Z}_{2}^{2} \rtimes {\mathbb Z}_{m}$ are definable over ${\mathbb Q}$Apr 03 2016Sep 15 2016It is well known that every closed Riemann surface $S$ of genus $g \geq 2$, admitting a group $G$ of conformal automorphisms so that $S/G$ has triangular signature, can be defined over a finite extension of ${\mathbb Q}$. It is interesting to know, in ... More
A family of relativistic charged thin disks with an inner edgeJun 14 2009A new family of exact solutions of the Einstein-Maxwell equations for static axially symmetric spacetimes is presented. The metric functions of the solutions are explicitely computed and are simply written in terms of the oblate spheroidal coordinates. ... More
Exact Static Axially Symmetric Thin Annular Dust DisksJun 04 2009A new family of exact solutions of the Einstein field equations for static and axially simmetric spacetimes is presented. All the metric functions of the solutions are explicitly computed and the obtained expressions are simply written in terms of oblate ... More
Tuning the two-electron hybridization and spin states in parallel-coupled InAs quantum dotsMar 01 2018We study spin transport in the one- and two-electron regimes of parallel-coupled double quantum dots (DQDs). The DQDs are formed in InAs nanowires by a combination of crystal-phase engineering and electrostatic gating, with an interdot tunnel coupling ... More
Relativistic static thin dust disks with an inner edge: An infinite family of new exact solutionsNov 24 2008An infinite family of new exact solutions of the Einstein vacuum equations for static and axially symmetric spacetimes is presented. All the metric functions of the solutions are explicitly computed and the obtained expressions are simply written in terms ... More
Charge separation in donor-C60 complexes with real-time Green's functions: The importance of nonlocal correlationsJan 23 2018We use the Nonequilibrium Green's Function (NEGF) method to perform real-time simulations of the ultrafast electron dynamics of photoexcited donor-C60 complexes modeled by a Pariser-Parr-Pople Hamiltonian. The NEGF results are compared to mean-field Hartree-Fock ... More
Spectroscopy and level detuning of few-electron spin states in parallel InAs quantum dotsAug 20 2018We use tunneling spectroscopy to study the evolution of few-electron spin states in parallel InAs nanowire double quantum dots (QDs) as a function of level detuning and applied magnetic field. Compared to the much more studied serial configuration, parallel ... More
Compatible associative bialgebrasNov 11 2017We introduce a non-symmetric operad $\mathcal{N}$, whose dimension in degree $n$ is given by the Catalan number $c_{n-1}$. It arises naturally in the study of coalgebra structures defined on compatible associative algebras. We prove that any free compatible ... More
SDSS-IV MaNGA: Inside-out vs. outside-in quenching in different local environmentsJan 16 2019The large Integral Field Spectroscopy (IFS) surveys have allowed the classification of ionizing sources of emission lines on sub-kpc scales. In this work, we define two non-parametric parameters, quiescence (f$_{q}$) and its concentration (c$_{q}$), to ... More
An Empirical Study of the L2-Boost technique with Echo State NetworksJan 02 2015A particular case of Recurrent Neural Network (RNN) was introduced at the beginning of the 2000s under the name of Echo State Networks (ESNs). The ESN model overcomes the limitations during the training of the RNNs while introducing no significant disadvantages. ... More
Cosmological implications of baryon acoustic oscillation (BAO) measurementsNov 04 2014Oct 09 2015We derive constraints on cosmological parameters and tests of dark energy models from the combination of baryon acoustic oscillation (BAO) measurements with cosmic microwave background (CMB) and Type Ia supernova (SN) data. We take advantage of high-precision ... More
Thomas-Fermi studies of pairing in inhomogeneous systems: nuclear and cold atom systems at overflowApr 16 2012A novel Thomas-Fermi (TF) approach to inhomogeneous superfluid Fermi-systems is presented and shown that it works well also in cases where the Local Density Approximation (LDA) breaks down. The novelty lies in the fact that the semiclassical approximation ... More