Results for "Andrés García-Suaza"

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Determining the number of factors in a forecast model by a random matrix test: cryptocurrenciesMay 02 2019We determine the number of statistically significant factors in a forecast model using a random matrices test. The applied forecast model is of the type of Reduced Rank Regression (RRR), in particular, we chose a flavor which can be seen as the Canonical ... More
Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type V. Mixed classes in Chevalley and Steinberg groupsDec 30 2018Jan 29 2019We show that all classes that are neither semisimple nor unipotent in finite simple Chevalley or Steinberg groups different from $PSL_n(q)$ collapse (i.e. are never the support of a finite-dimensional Nichols algebra). As a consequence, we prove that ... More
Distribution Regression in Duration Analysis: an Application to Unemployment SpellsApr 12 2019This article proposes estimation and inference procedures for distribution regression models with randomly right-censored data. The proposal generalizes classical duration models to a situation where slope coefficients can vary with the elapsed duration, ... More
Implicit Lagrange-Routh Equations and Dirac ReductionSep 07 2015Feb 25 2016In this paper, we make a generalization of Routh's reduction method for Lagrangian systems with symmetry to the case where not any regularity condition is imposed on the Lagrangian. First, we show how implicit Lagrange-Routh equations can be obtained ... More
Reduced dynamics and Lagrangian submanifolds of symplectic manifoldsFeb 12 2014May 19 2014In this paper, we will see that the symplectic creed by Weinstein "everything is a Lagrangian submanifold" also holds for Hamilton-Poincar\'e and Lagrange-Poincar\'e reduction. In fact, we show that solutions of the Hamilton-Poincar\'e equations and of ... More
Correlations and Flow of Information between The New York Times and Stock MarketsJul 18 2017We use Random Matrix Theory (RMT) and information theory to analyze the correlations and flow of information between 64,939 news from The New York Times and 40 world financial indices during 10 months along the period 2015-2016. The set of news was quantified ... More
Ga+, In+ and Tl+ Impurities in Alkali Halide Crystals: Distortion TrendsAug 30 2000A computational study of the doping of alkali halide crystals (AX: A = Na, K; X = Cl, Br) by ns2 cations (Ga+, In+ and Tl+) is presented. Active clusters of increasing size (from 33 to 177 ions) are considered in order to deal with the large scale distortions ... 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
Extreme values for $S_n(σ,t)$ near the critical lineJul 31 2018Let $S(\sigma,t)=\frac{1}{\pi}\arg\zeta(\sigma+it)$ be the argument of the Riemann zeta function at the point $\sigma+it$ of the critical strip. For $n\geq 1$ and $t>0$ we define $$ S_{n}(\sigma,t) = \int_0^t S_{n-1}(\sigma,\tau)\,d\tau\, + \delta_{n,\sigma\,}, ... More
An orbital-free molecular dynamics study of melting in K_20, K_55, K_92, K_142, Rb_55 and Cs_55 clustersMay 22 2000Feb 24 2001The melting-like transition in potasium clusters K_N, with N=20, 55, 92 and 142, is studied by using an orbital-free density-functional constant-energy molecular dynamics simulation method, and compared to previous theoretical results on the melting-like ... More
Melting behavior of large disordered sodium clustersMay 18 2000The melting-like transition in disordered sodium clusters Na_N, with N=92 and 142 is studied by using a first-principles constant-energy molecular dynamics simulation method. Na_142, whose atoms are distributed in two (surface and inner) main shells with ... More
Living Without a Mobile Phone: An AutoethnographyApr 13 2018This paper presents an autoethnography of my experiences living without a mobile phone. What started as an experiment motivated by a personal need to reduce stress, has resulted in two voluntary mobile phone breaks spread over nine years (i.e., 2002-2008 ... 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
A finitely generated, locally indicable group with no faithful action by C^1 diffeomorphisms of the intervalFeb 26 2009According to Thurston's stability theorem, every group of C^1 diffeomorphisms of the closed interval is locally indicable (.e., every finitely generated subgroup factors through Z). We show that, even for finitely generated groups, the converse of this ... 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.
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
A decreasing step method for strongly oscillating stochastic modelsOct 07 2012Mar 18 2015We propose an algorithm for approximating the solution of a strongly oscillating SDE, that is, a system in which some ergodic state variables evolve quickly with respect to the other variables. The algorithm profits from homogenization results and consists ... More
Statistics of incompressible hydrodynamic turbulence: an alternative approachSep 19 2018Jan 26 2019Using a recent alternative form of the Kolmogorov-Monin exact relation for fully developed hydrodynamics (HD) turbulence, the incompressible energy cascade rate $\varepsilon$ is computed. Under this current theoretical framework, for three-dimensional ... More
Multipoint flux mixed finite element methods for slightly compressible flow in porous mediaNov 06 2018In this paper, we consider multipoint flux mixed finite element discretizations for slightly compressible Darcy flow in porous media. The methods are formulated on general meshes composed of triangles, quadrilaterals, tetrahedra or hexahedra. An inexact ... More
Driven and undriven states of multicomponent granular gases of inelastic and rough hard disks or spheresJan 31 2019Starting from a recent derivation of the energy production rates in terms of the number of translational and rotational degrees of freedom, a comparative study on different granular temperatures in gas mixtures of inelastic and rough disks or spheres ... More
An Alternative Derivation of the Analytic Expression of Transmission SpectraAug 16 2018Under some assumptions, an analytic expression for the transmission spectrum can be obtained, which can form the basis of atmospheric retrievals and allows insight on the degeneracies involved. In this Research Note we present an alternative derivation ... More
Indexed Dynamic Programming to boost Edit Distance and LCSS ComputationJun 12 2018There are efficient dynamic programming solutions to the computation of the Edit Distance from $S\in[1..\sigma]^n$ to $T\in[1..\sigma]^m$, for many natural subsets of edit operations, typically in time within $O(nm)$ in the worst-case over strings of ... More
Detection of a diffuse extended halo-like structure around 47 TucAug 21 2017We constructed for the first time a stellar density profile of 47 Tucanae (47 Tuc) out of $\sim$ 5.5 times its tidal radius ($r_t$) using high-quality deep $BV$ photometry. After carefully considering the influence of photometric errors, and Milky Way ... More
A BV-algebra Structure on Hochschild Cohomology of the Group Ring of Finitely Generated Abelian GroupsApr 10 2017We study a Batalin-Vilkovisky algebra structure on the Hochschild cohomology of the group ring of finitely generated abelian groups. The Batalin-Vilkovisky algebra structure for finite abelian groups comes from the fact that the group ring of finite groups ... More
Bounding $S_n(t)$ on the Riemann hypothesisFeb 14 2017Let $S(t) = \tfrac{1}{\pi} \arg \zeta (\frac12 + it)$ be the argument of the Riemann zeta-function at the point $\tfrac12 + it$. For $n \geq 1$ and $t>0$ define its iterates \begin{equation*} S_n(t) = \int_0^t S_{n-1}(\tau) \,{\rm d}\tau\, + \delta_n\,, ... More
Calibration of semi-analytic models of galaxy formation using Particle Swarm OptimizationOct 25 2013Jan 29 2015We present a fast and accurate method to select an optimal set of parameters in semi-analytic models of galaxy formation and evolution (SAMs). Our approach compares the results of a model against a set of observables applying a stochastic technique called ... More
Extensions of finite quantum groups by finite groupsAug 26 2006Mar 27 2008We give a necessary and sufficient condition for two Hopf algebras presented as central extensions to be isomorphic, in a suitable setting. We then study the question of isomorphism between the Hopf algebras constructed in 0707.0070v1 as quantum subgroups ... More
Chemical Vapor Deposition Growth of Boron-Carbon-Nitrogen layers from Methylamine Borane Thermolysis ProductsFeb 20 2019This work investigates the growth of B-C-N layers by chemical vapor deposition using methylamine borane (MeAB) as single-source precursor. MeAB has been synthesized and characterized, paying particular attention to the analysis of its thermolysis products, ... More
Non-adiabatic entropy production for non-Markov dynamicsMay 16 2012Sep 06 2012We extend the definition of non-adiabatic entropy production given for Markovian systems in [M. Esposito and C. Van den Broeck, Phys. Rev. Lett. 104 090601, (2010)], to arbitrary non-Markov ergodic dynamics. We also introduce a notion of stability characterizing ... More
Coefficients and higher order derivatives of cyclotomic polynomials: old and newMay 14 2018Aug 22 2018The $n^{th}$ cyclotomic polynomial $\Phi_n(x)$ is the minimal polynomial of an $n^{th}$ primitive root of unity. Its coefficients are the subject of intensive study and some formulas are known for them. Here we are interested in formulas which are valid ... More
Un-reduction of systems of second-order ordinary differential equationsJun 24 2016In this paper we consider an alternative approach to "un-reduction". This is the process where one associates to a Lagrangian system on a manifold a dynamical system on a principal bundle over that manifold, in such a way that solutions project. We show ... More
Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type III. Semisimple classes in PSL(n,q)Jun 22 2015Jun 29 2015We show that Nichols algebras of most simple Yetter-Drinfeld modules over the projective special linear group over a finite field, corresponding to semisimple orbits, have infinite dimension. We introduce a new criterium to determine when a conjugacy ... More
Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type IV. Unipotent classes in Chevalley and Steinberg groupsDec 23 2016We show that all unipotent classes in finite simple Chevalley or Steinberg groups, different from PSL_n(q) and PSp_{2n}(q), collapse (i.e. are never the support of a finite-dimensional Nichols algebra), with a possible exception on one class of involutions ... More
Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type I. Non-semisimple classes in PSL(n,q)Dec 21 2013Jul 01 2014We show that Nichols algebras of most simple Yetter-Drinfeld modules over the projective special linear group over a finite field, corresponding to non-semisimple orbits, have infinite dimension. We spell out a new criterium to show that a rack collapses. ... More
Cohort aggregation modelling for complex forest stands: Spruce-aspen mixtures in British ColumbiaOct 24 2016Oct 25 2016Mixed-species growth models are needed as a synthesis of ecological knowledge and for guiding forest management. Individual-tree models have been commonly used, but the difficulties of reliably scaling from the individual to the stand level are often ... More
Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type III. Semisimple classes in PSL(n,q)Jun 22 2015Mar 12 2018We show that Nichols algebras of most simple Yetter-Drinfeld modules over the projective special linear group over a finite field, corresponding to semisimple orbits, have infinite dimension. We introduce a new criterium to determine when a conjugacy ... More
O-asymptotic classes of finite structuresOct 09 2014In this paper we introduce the concept of O-asymptotic classes of finite structures, melding ideas coming from 1-dimensional asymptotic classes and o-minimality. The results we present here include a cell-decomposition result for O-asymptotic classes ... More
$L^p$-$L^q$ estimates for Electromagnetic Helmholtz equation. Singular potentialsOct 09 2013In space dimension $n\geq3$, we consider the electromagnetic Schr\"odinger Hamiltonian $H=(\nabla-iA(x))^2+V$ and the corresponding Helmholtz equation (\nabla-iA(x))^2u+u+V(x)u=f\quad \text{in}\quad \mathbb{R}^n, where the magnetic and electric potentials ... More
Toeplitz minors and specializations of skew Schur polynomialsJun 08 2017Nov 27 2017We express minors of Toeplitz matrices of finite and large dimension, including the case of symbols with Fisher-Hartwig singularities, in terms of specializations of symmetric functions. By comparing the resulting expressions with the inverses of some ... More
Duration of local violations of the second law of thermodynamics along single trajectories in phase spaceDec 04 2012Feb 03 2014We define the {\it violation fraction} $\nu$ as the cumulative fraction of time that the entropy change is negative during single realizations of processes in phase space. This quantity depends both on the number of degrees of freedom $N$ and the duration ... More
Symmetry for the duration of entropy-consuming intervalsMar 10 2014Apr 28 2014We introduce the violation fraction $\upsilon$ as the cumulative fraction of time that a mesoscopic system spends consuming entropy at a single trajectory in phase space. We show that the fluctuations of this quantity are described in terms of a symmetry ... More
Matrix models for classical groups and Toeplitz$\pm $Hankel minors with applications to Chern-Simons theory and fermionic modelsJan 25 2019We study matrix integration over the classical Lie groups $U(N),Sp(2N),O(2N)$ and $O(2N+1)$, using symmetric function theory and the equivalent formulation in terms of determinants and minors of Toeplitz$\pm$Hankel matrices. We establish a number of factorizations ... More
Estimating reducible stochastic differential equations by conversion to a least-squares problemOct 16 2017Jun 23 2018Stochastic differential equations (SDEs) are increasingly used in longitudinal data analysis, compartmental models, growth modelling, and other applications in a number of disciplines. Parameter estimation, however, currently requires specialized software ... More
Routh reduction for first-order field theoriesJul 10 2018Nov 13 2018We present a reduction theory for first order Lagrangian field theories which takes into account the conservation of momenta. The relation between the solutions of the original problem with a prescribed value of the momentum and the solutions of the reduced ... More
Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type II. Unipotent classes in symplectic groupsDec 23 2014We show that Nichols algebras of most simple Yetter-Drinfeld modules over the projective symplectic linear group over a finite field, corresponding to unipotent orbits, have infinite dimension. We give a criterium to deal with unipotent classes of general ... More
Isolated factorizations and their applications in simplicial affine semigroupsApr 03 2018We introduce the concept of isolated factorizations of an element of a commutative monoid and study its properties. We give several bounds for the number of isolated factorizations of simplicial affine semigroups and numerical semigroups. We also generalize ... More
Un-Reduction of Systems of Second-Order Ordinary Differential EquationsJun 24 2016Dec 07 2016In this paper we consider an alternative approach to "un-reduction". This is the process where one associates to a Lagrangian system on a manifold a dynamical system on a principal bundle over that manifold, in such a way that solutions project. We show ... More
On the eigenvalues of a class of matrices with displacement structure arising in optimal controlAug 27 2018In this work we present a framework for studying the eigenvalues of a family of matrices with a particular displacement structure. The family admits a specific decomposition as the product of an upper and a lower triangular matrices having an increasing ... More
Strong Bisimulation for Control OperatorsJun 22 2019The purpose of this paper is to identify programs with control operators whose reduction semantics are in exact correspondence. This is achieved by introducing a relation $\simeq$, defined over a revised presentation of Parigot's $\lambda\mu$-calculus ... More
Towards the solution of some fundamental questions concerning group actions on the circle and codimension-one foliationsDec 15 2013Sep 07 2014We consider finitely generated groups of real-analytic circle diffeomorphisms. We show that if such a group admits an exceptional minimal set (i.e., a minimal invariant Cantor set), then its Lebesgue measure is zero; moreover, there are only finitely ... More
An Empirical Study of Customer Spillover Learning about Service QualityJul 20 2016"Spillover" learning is defined as customers' learning about the quality of a service (or product) from their previous experiences with similar yet not identical services. In this paper, we propose a novel, parsimonious and general Bayesian hierarchical ... More
Laying the Groundwork for a Worker-Centric Peer EconomyJul 21 2018The "gig economy" has transformed the ways in which people work, but in many ways these markets stifle the growth of workers and the autonomy and protections that workers have grown to expect. We explored the viability of a "worker centric peer economy"--a ... More
Exact law for homogeneous compressible Hall magnetohydrodynamics turbulenceJul 28 2017We derive the exact law for three-dimensional (3D) homogeneous compressible isothermal Hall magnetohydrodynamics (CHMHD) turbulence, without the assumption of isotropy. The Hall current is shown to introduce new flux and sources terms that act at the ... More
Bandlimited approximations and estimates for the Riemann zeta-functionOct 28 2017In this paper, we provide explicit upper and lower bounds for the argument of the Riemann zeta-function and its antiderivatives in the critical strip under the assumption of the Riemann hypothesis. This extends the previously known bounds for these quantities ... More
Understanding and enhancing superconductivity in FeSe/STO by quantum size effectsJun 30 2016Nov 24 2016Superconductivity in one-atom-layer iron selenide (FeSe) on a strontium titanate (STO) substrate is enhanced by almost an order of magnitude with respect to bulk FeSe. There is recent experimental evidence suggesting that this enhancement persists in ... More
Understanding and enhancing superconductivity in FeSe/STO by quantum size effectsJun 30 2016Superconductivity in one-atom-layer iron selenide (FeSe) on a strontium titanate (STO) substrate is enhanced by almost an order of magnitude with respect to bulk FeSe. There is recent experimental evidence suggesting that this enhancement persists in ... More
Detection of protonated formaldehyde in the prestellar core L1689BMar 01 2016Complex organic molecules (COMs) are detected in many regions of the interstellar medium, including prestellar cores. However, their formation mechanisms in cold (~10 K) cores remain to this date poorly understood. The formyl radical HCO is an important ... More
On convex polyhedron semigroupsJul 16 2015Let $\mathbf{F}$ be bounded convex polyhedron of $\R^3_{\geq}$ and $\psi_k$ the homothety with center the origin and radius $k$. The convex polyhedron semigroup associated to $\mathbf{F}$ is the semigroup $\cup_{k\in\N}\psi_k(\mathbf{F})\cap \N^3$. In ... More
Disconnected pseudo-$C_\ell$ covariances for projected large-scale structure dataJun 27 2019The disconnected part of the power spectrum covariance matrix (also known as the "Gaussian" covariance) is the dominant contribution on large scales for galaxy clustering and weak lensing datasets. The presence of a complicated sky mask causes non-trivial ... More
Quantum hypercomputation based on the dynamical algebra su(1,1)Feb 09 2006Feb 14 2006An adaptation of Kieu's hypercomputational quantum algorithm (KHQA) is presented. The method that was used was to replace the Weyl-Heisenberg algebra by other dynamical algebra of low dimension that admits infinite-dimensional irreducible representations ... More
Numerical Simulations of a Possible Hypercomputational Quantum AlgorithmApr 05 2005The hypercomputers compute functions or numbers, or more generally solve problems or carry out tasks, that cannot be computed or solved by a Turing machine. Several numerical simulations of a possible hypercomputational algorithm based on quantum computations ... More
Existence of dicritical singularities of Levi-flat hypersurfaces and holomorphic foliationsNov 14 2016Nov 28 2017We study holomorphic foliations tangent to singular real-analytic Levi-flat hypersurfaces in compact complex manifolds of complex dimension two. We give some hypotheses to guarantee the existence of dicritical singularities of these objects. As consequence, ... More
Online Learning for Non-Stationary A/B TestsFeb 14 2018May 27 2018The rollout of new versions of a feature in modern applications is a manual multi-stage process, as the feature is released to ever larger groups of users, while its performance is carefully monitored. This kind of A/B testing is ubiquitous, but suboptimal, ... More
Call-by-need, neededness and all thatJan 31 2018We show that call-by-need is observationally equivalent to weak-head needed reduction. The proof of this result uses a semantical argument based on a (non-idempotent) intersection type system called $\mathcal{V}$. Interestingly, system $\mathcal{V}$ also ... More
Deep Washington photometry of inconspicuous star cluster candidates in the Large Magellanic CloudOct 27 2014Oct 29 2014We present deep Washington photometry of 45 poorly populated star cluster candidates in the Large Magellanic Cloud (LMC). We have performed a systematic study to estimate the parameters of the cluster candidates by matching theoretical isochrones to the ... More
Anosov representations and dominated splittingsMay 05 2016Jun 13 2017We provide a link between Anosov representations introduced by Labourie and dominated splitting of linear cocycles. This allows us to obtain equivalent characterizations for Anosov representations and to recover recent results due to Gu\'eritaud-Guichard-Kassel-Wienhard ... More
On the ergodic theory of free group actions by real-analytic circle diffeomorphismsDec 15 2013Nov 02 2016We consider finitely generated groups of real-analytic circle diffeomorphisms. We show that if such a group admits an exceptional minimal set (i.e., a minimal invariant Cantor set), then its Lebesgue measure is zero; moreover, there are only finitely ... More
Pair Correlation Estimates for the Zeros of the Zeta-Function via Semidefinite ProgrammingOct 20 2018In this paper we study the distribution of the non-trivial zeros of the zeta-function $\zeta(s)$ (and other L-functions) under Montgomery's pair correlation approach. We use semidefinite programming to improve the asymptotic bounds for $N^*(T)$, $N_d(T)$ ... More
Routh reduction and the class of magnetic Lagrangian systemsMar 15 2012Jun 08 2012In this paper, some new aspects related to Routh reduction of Lagrangian systems with symmetry are discussed. The main result of this paper is the introduction of a new concept of transformation that is applicable to systems obtained after Routh reduction ... More
Vector-borne disease risk indexes in spatially structured populationsOct 11 2017There are economic and physical limitations when applying prevention and control strategies for urban vector borne diseases. Consequently, there are increasing concerns and interest in designing efficient strategies and regulations that health agencies ... More
Marginal and Irrelevant Disorder in Einstein-Maxwell backgroundsDec 01 2015Jan 15 2016We study analytically the effect of a weak random chemical potential of zero average in an Einstein-Maxwell background. For uncorrelated disorder this perturbation is relevant however we show that it can become marginal or even irrelevant by tuning disorder ... More
Onset of the ridge structure in AA, pA and pp collisionsMay 14 2014Dec 12 2014It is shown that the anomalous sharp increasing of the strength of the near-side ridge structures observed in Au-Au collisions at $\sqrt{s}=$ 62 GeV and $\sqrt{s}=$ 200 GeV and the onset of the ridge structure in pPb and in pp collisions can be naturally ... More
A branch-point approximant for the equation of state of hard spheresMar 23 2009Jun 26 2009Using the first seven known virial coefficients and forcing it to possess two branch-point singularities, a new equation of state for the hard-sphere fluid is proposed. This equation of state predicts accurate values of the higher virial coefficients, ... More
Ultra-short Pulse Propagation in Nonlinear OpticsJun 27 2018In this work, we perform a detailed review about the theoretical modeling of the optical propagation of ultra-short pulses in different scenarios of nonlinear optics. In particular, we focus our efforts on optical fibers and uniform media, with special ... More
Bigraded cochain complexes and Poisson cohomologyMar 05 2019We present an algebraic framework for the computation of low-degree cohomology of a class of bigraded complexes which arise in Poisson geometry around (pre)symplectic leaves. We also show that this framework can be applied to the more general context ... More
Measuring micro-displacements of specular surfaces using speckle interferometryDec 24 2018The displacement field of an object surface can be measured by using speckle interferometry. This technique is based on the phenomenon of laser speckle and consists in correlating speckle interferograms taken after and before the deformation of the surface. ... More
Towards a comprehensive model of Earth's disk-integrated Stokes vectorSep 30 2014A significant body of work on simulating the remote appearance of Earth-like exoplanets has been done over the last decade. The research is driven by the prospect of characterizing habitable planets beyond the Solar System in the near future. In this ... More
Time dependent quantum scattering theory on complete manifolds with a corner of codimension 2Oct 19 2012Sep 23 2015We show the existence and orthogonality of wave operators naturally associated to a compatible Laplacian on a complete manifold with a corner of codimension 2. In fact, we prove asymptotic completeness i.e. that the image of these wave operators is equal ... More
Absence of singular continuous spectrum for some geometric LaplaciansOct 19 2012We provide two examples of spectral analysis techniques of Schroedinger operators applied to geometric Laplacians. In particular we show how to adapt the method of analytic dilation to Laplacians on complete manifolds with corners of codimension 2 finding ... More
Measuring Cultural Dynamics Through the Eurovision Song ContestJan 14 2013May 10 2013Measuring culture and its dynamics through surveys has important limitations, but the emerging field of computational social science allows us to overcome them by analyzing large-scale datasets. In this article, we study cultural dynamics through the ... More
About the Geometric Solution to the Problems of Dark EnergyNov 19 2010Feb 06 2011In this paper is proposed a geometric solution to the dark energy, assuming that the space can be divided into regions of size $\sim L_{p}$ and energy $\sim E_{p}$. Significantly this assumption generate a energy density similar to the energy density ... More
Exact Solutions for Restricted Incompressible Navier--Stokes Equations with Dirichlet Boundary ConditionsJul 28 2017Mar 03 2019In this paper it is exposed how to obtain a relation that have to be hold for all free divergent velocity fields that evolve according to Navier--Stokes equations. However, checking the violation of this relation requires a huge computational effort. ... More
On mapping exoplanet atmospheres with high-dispersion spectro-polarimetry. Some model predictionsFeb 03 2018Planets reflect and linearly polarize the radiation that they receive from their host stars. The emergent polarization is sensitive to aspects of the planet atmosphere such as the gas composition and the occurrence of condensates and their optical properties. ... More
Degenerate Hessian structures on radiant manifoldsMar 02 2015Sep 29 2017We present a rigorous mathematical treatment of Ruppeiner geometry, by considering degenerate Hessian metrics defined on radiant manifolds. A manifold $M$ is said to be radiant if it is endowed with a symmetric, flat connection $\bar\nabla$ and a global ... More
Solar Axion search with Micromegas detectors in the CAST Experiment with $^{3}$He as buffer gasJun 08 2015Axions are well motivated particles proposed in an extension of the SM as a solution to the strong CP problem. Also, there is the category of Axion-Like Particles (ALPs) which appear in extensions of the SM and share the same phenomenology of the axion. ... More
Automated asteroseismic peak detectionsJan 29 2018Space observatories such as $\textit{Kepler}$ have provided data that can potentially revolutionise our understanding of stars. Through detailed asteroseismic analyses we are capable of determining fundamental stellar parameters and reveal the stellar ... More
Optical Supersymmetry in the Time DomainMar 24 2019Originally emerged within the context of string and quantum field theory, and later fruitfully extrapolated to photonics, the algebraic transformations of quantum-mechanical supersymmetry were conceived in the space realm. Here, we introduce a paradigm ... More
Aspects of reduction and transformation of Lagrangian systems with symmetryFeb 06 2014This paper contains results on geometric Routh reduction and it is a continuation of a previous paper where a new class of transformations is introduced between Lagrangian systems obtained after Routh reduction. In general, these reduced Lagrangian systems ... More
Combined effect of thermal and quantum fluctuations in superconducting nanostructures: a path integral approachSep 20 2011We study the combined effect of thermal and quantum fluctuations in a zero dimensional superconductor. By using path integral techniques, we obtain novel expressions for the partition function and the superconducting order parameter which include both ... More
Universal quantum constraints on the butterfly effectOct 29 2015Jul 05 2016Lyapunov exponents, a purely classical quantity, play an important role in the evolution of quantum chaotic systems in the semiclassical limit. We conjecture the existence of an upper bound on the Lyapunov exponents that contribute to the quantum motion, ... More
Interplay of classical and "quantum" capacitance in a one dimensional array of Josephson junctionsDec 11 2013Even in the absence of Coulomb interactions phase fluctuations induced by quantum size effects become increasingly important in superconducting nano-structures as the mean level spacing becomes comparable with the bulk superconducting gap. Here we study ... More
Many-Body Localization in a finite-range Sachdev-Ye-Kitaev modelJan 10 2018We study the level statistics of a generalized Sachdev-Ye-Kitaev (SYK) model with two-body and one-body random interactions of finite range by exact diagonalization. Tuning the range of the one-body term, while keeping the two-body interaction sufficiently ... More
Rare Flavor Processes in Maximally Natural SupersymmetrySep 19 2014Feb 23 2015We study CP-conserving rare flavor violating processes in the recently proposed theory of Maximally Natural Supersymmetry (MNSUSY). MNSUSY is an unusual supersymmetric (SUSY) extension of the Standard Model (SM) which, remarkably, is un-tuned at present ... More
Conductivity and entanglement entropy of high dimensional holographic superconductorsFeb 12 2015Jan 13 2016We investigate the dependence of the conductivity and the entanglement entropy on the space-time dimensionality $d$ in two holographic superconductors: one dual to a quantum critical point with spontaneous symmetry breaking, and the other modeled by a ... More
Size effects in superconducting thin films coupled to a substrateNov 17 2013Jan 13 2016Recent experimental advances in surface science have made it possible to track the evolution of superconductivity in films as the thickness enters the nanoscale region where it is expected that the substrate plays an important role. Here, we put forward ... More
Drude weight and Mazur-Suzuki bounds in holographyDec 14 2015We investigate the Drude weight and the related Mazur-Suzuki (MS) bound in a broad variety of strongly coupled field theories with a gravity dual at finite temperature and chemical potential. We revisit the derivation of the recently proposed universal ... More
Non equilibrium stationary states of a kicked linear chain of spins coupled to a heat bathNov 06 2016We consider a linear chain made of spins of one half in contact with a finite temperature environment for which periodic delta-kicks are applied to the qubits of the linear chain in two different ways: periodic kicks are applied to a single qubit and ... More
Thermodynamic inference based on coarse-grained data or noisy measurementsDec 23 2015Fluctuation theorems have become an important tool in single molecule biophysics to measure free energy differences from non-equilibrium experiments. When significant coarse-graining or noise affect the measurements, the determination of the free energies ... More