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
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
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
Vacuum effective actions and mass-dependent renormalization in curved spaceFeb 08 2019Mar 02 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
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
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
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
Worldline Formalism in Snyder SpacesJun 29 2018We study the $\phi_{\star}^4$ model for a scalar field in a linearization of the Snyder model, using the methods of the Worldline Formalism. Our main result is a master equation for the 1-loop n-point function. From this we derive the renormalization ... 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
Thermodynamics in the NC discMar 15 2018We study the thermodynamics of a scalar field on a noncommutative disc implementing the boundary as the limit case of an interaction with an appropriately chosen confining background. We explicitly obtain expressions for thermodynamic potentials of gases ... 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
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
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
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
A geometric simulation theorem on direct products of finitely generated groupsJun 02 2017Jul 17 2018We show that every effectively closed action of a finitely generated group $G$ on a closed subset of $\{0,1\}^{\mathbb{N}}$ can be obtained as a topological factor of the $G$-subaction of a $(G \times H_1 \times H_2)$-subshift of finite type (SFT) for ... 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
Homological invariants relating the super Jordan plane to the Virasoro algebraJul 17 2017Aug 05 2017Nichols algebras are an important tool for the classification of Hopf algebras. Within those with finite GK dimension, we study homological invariants of the super Jordan plane, that is, the Nichols algebra $A=B(V(-1,2))$. These invariants are Hochschild ... More
Graded Quivers, Generalized Dimer Models and Toric GeometryApr 16 2019The open string sector of the topological B-model model on CY $(m+2)$-folds is described by $m$-graded quivers with superpotentials. This correspondence extends to general $m$ the well known connection between CY $(m+2)$-folds and gauge theories on the ... 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
Mildly Suppressed Star Formation in Central Regions of MaNGA Seyfert GalaxiesSep 30 2018Negative feedback from accretion onto super-massive black holes (SMBHs), that is to remove gas and suppress star formation in galaxies, has been widely suggested. However, for Seyfert galaxies which harbor less active, moderately accreting SMBHs in the ... More
Study of the core-crust transition in neutron stars with finite-range interactions: the dynamical methodApr 13 2019The properties of the core-crust transition in neutron stars are investigated using effective nuclear forces of finite-range. Special attention is paid to the so-called dynamical method for locating the transition point, which, apart from the stability ... More
On the connectedness of the singular locus of the moduli space of principally polarized abelian varietiesAug 22 2017Apr 05 2018Let $\mathcal{A}_g$ denote the moduli space of principally polarized abelian varieties of dimension $g \ge 3.$ In this paper we prove the connectedness of the singular sublocus of $\mathcal{A}_g$ consisting of those abelian varieties which possess an ... More
Lectures on the Euler characteristic of affine manifoldsFeb 10 2018These are lecture notes prepared for the summer school "Geometric, algebraic and topological methods in quantum field theory", held in Villa de Leyva in July 2017. Our goal is to provide an introduction to a conjecture of Chern that states that the Euler ... More
Setting the Agenda: Different strategies of a Mass Media in a model of cultural disseminationDec 29 2015Day by day, people exchange opinions about a given new with relatives, friends, and coworkers. In most cases, they get informed about a given issue by reading newspapers, listening to the radio, or watching TV, i.e., through a Mass Media (MM). However, ... More
Single-sided Real-time PESQ Score EstimationDec 27 2012For several years now, the ITU-T's Perceptual Evaluation of Speech Quality (PESQ) has been the reference for objective speech quality assessment. It is widely deployed in commercial QoE measurement products, and it has been well studied in the literature. ... 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
Quantifying time-dependent Media Agenda and Public Opinion by topic modelingJul 13 2018Apr 03 2019The mass media plays a fundamental role in the formation of public opinion, either by defining the topics of discussion or by making an emphasis on certain issues. Directly or indirectly, people get informed by consuming news from the media. Naturally, ... More
Planetesimal fragmentation and giant planet formation II: dependencies with planetesimal relative velocities and compositionsMar 28 2019Most of planet formation models that incorporate planetesimal fragmentation consider a catastrophic impact energy threshold for basalts at a constant velocity of 3 km/s during all the process of the formation of the planets. However, as planets grow the ... More
Partitioning edge-coloured hypergraphs into few monochromatic tight cyclesMar 11 2019Confirming a conjecture of Gy\'arf\'as, we prove that, for all natural numbers $k$ and $r$, the vertices of every $r$-edge-coloured complete $k$-uniform hypergraph can be partitioned into a bounded number (independent of the size of the hypergraph) of ... More
Parallel-in-time optical simulation of history statesJan 15 2019We present an experimental optical implementation of a parallel-in-time discrete model of quantum evolution, based on the entanglement between the quantum system and a finite dimensional quantum clock. The setup is based on a programmable spatial light ... 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
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 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
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
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
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
Applying the simplest Kochen-Specker set for quantum information processingAug 28 2014Kochen-Specker (KS) sets are key tools for proving some fundamental results in quantum theory and also have potential applications in quantum information processing. However, so far, their intrinsic complexity has prevented experimentalists from using ... 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
Tests of a dual-readout fiber calorimeter with SiPM light sensorsMay 08 2018In this paper, we describe the first tests of a dual-readout fiber calorimeter in which silicon photomultipliers are used to sense the (scintillation and Cherenkov) light signals. The main challenge in this detector is implementing a design that minimizes ... More
Optical Integral Field Spectroscopy observations applied to simulated galaxies: Testing the fossil record methodNov 12 2018Nov 27 2018By means of post-processed cosmological Hydrodynamics simulations we explore the ability of the fossil record method to recover the stellar mass, age gradients, and global/radial star formation and mass growth histories of galaxies observed with an optical ... 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
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
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
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
Characterizing the local relation between star formation rate and gas-phase metallicity in MaNGA spiral galaxiesApr 08 2019The role of gas accretion in galaxy evolution is still a matter of debate. The presence of inflows of metal-poor gas that trigger star formation bursts of low metallicity has been proposed as an explanation for the local anti-correlation between star ... 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
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
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
Robust Heteroclinic TangenciesMar 01 2019We construct diffeomorphisms in dimension $d\geq 2$ exhibiting $C^1$-robust heteroclinic tangencies.
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
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
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
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
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
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
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
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
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.
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
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
Branes on $G$-manifoldsJan 27 2017Let $X$ be Calabi-Yau manifold acted by a group $G$. We give a definition of $G$-equivariance for branes on $X$, and assign to each equivariant brane an element of the equivariant cohomology of $X$ that can be considered as a charge of the brane. We prove ... 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
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
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
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
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
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
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
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
Transverse Josephson vortices and localized states in stacked Bose-Einstein condensatesOct 14 2018Stacks of Bose-Einstein condensates coupled by long Josephson junctions present a rich phenomenology susceptible of experimental realization. We show that transverse Bloch waves excited in an array of one-dimensional condensates can carry tunneling super ... 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
Transverse Josephson vortices and localized states in stacked Bose-Einstein condensatesOct 14 2018Apr 13 2019The stacks of Bose-Einstein condensates coupled by long Josephson junctions present a rich phenomenology feasible to experimental realization and specially suitable for technological applications as the nonlinear-optics and superconducting analogues have ... 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
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
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
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
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
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
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
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
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
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
On the Thomas-Fermi approximation for Bose condensates in trapsOct 14 1998Thomas-Fermi theory for Bose condesates in inhomogeneous traps is revisited. The phase-space distribution function in the Thomas-Fermi limit is $f_0(\bold{R},\bold{p})$ $\alpha$ $\delta(\mu - H_{cl})$ where $H_{cl}$ is the classical counterpart of the ... 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
Stability Peninsulas on the Neutron Drip LineJun 29 2011Nov 28 2011Using HF+BCS method with Skyrme forces we analyze the neutron drip line. It is shown that around magic and new magic numbers the drip line may form stability peninsulas. It is shown the location of these peninsulas does not depend on the choice of Skyrme ... More
Suppression of Superfluidity upon Overflow of Trapped Fermions. Quantal and Thomas-Fermi StudiesOct 06 2011Two issues are treated in this work: (i) the generic fact that if a fermionic superfluid in the BCS regime overflows from a narrow container into a much wider one, pairing is much suppressed at the overflow point. Physical examples where this feature ... More
Fiber and Crystals Dual Readout calorimetersNov 11 2016The RD52 (DREAM) collaboration is performing R\&D on dual readout calorimetry techniques with the aim of improving hadronic energy resolution for future high energy physics experiments. The simultaneous detection of Cherenkov and scintillation light enables ... More
Fiber and Crystals Dual Readout calorimetersNov 11 2016Nov 14 2016The RD52 (DREAM) collaboration is performing R\&D on dual readout calorimetry techniques with the aim of improving hadronic energy resolution for future high energy physics experiments. The simultaneous detection of Cherenkov and scintillation light enables ... More
Resistive MSGC with double layered electrodesMar 31 2014The first successful attempts to optimize the electric field in Resistive Microstrip Gas Chamber (RMSGC) using additional field shaping strips located inside the detector substrate are described.