Results for "Raquel Villacampa"

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Abelian Balanced Hermitian structures on unimodular Lie algebrasDec 22 2014Let $\mathfrak{g}$ be a $2n$-dimensional unimodular Lie algebra equipped with a Hermitian structure $(J,F)$ such that the complex structure $J$ is abelian and the fundamental form $F$ is balanced. We prove that the holonomy group of the associated Bismut ... More
Laplacian coflow for warped $\mathrm{G}_2$-structuresApr 12 2019We consider the Laplacian coflow of a $\mathrm{G}_2$-structure on warped products of the form $M^7= M^6 \times_f S^1$ with $M^6$ a compact 6-manifold endowed with an $\mathrm{SU}(3)$-structure. We give an explicit reinterpretation of this flow as a set ... More
A family of complex nilmanifolds with infinitely many real homotopy typesDec 21 2017We find a one-parameter family of non-isomorphic nilpotent Lie algebras $\mathfrak{g}_a$, with $a \in [0,\infty)$, of real dimension eight with (strongly non-nilpotent) complex structures. By restricting $a$ to take rational values, we arrive at the existence ... More
Solutions of the Laplacian flow and coflow of a Locally Conformal Parallel $\mathrm{G}_2$-structureNov 23 2017We study the Laplacian flow of a $\mathrm{G}_2$-structure where this latter structure is claimed to be Locally Conformal Parallel. The first examples of long time solutions of this flow with the Locally Conformal Parallel condition are given. These examples ... More
On Gauduchon connections with Kähler-like curvatureSep 07 2018We study Hermitian metrics with a Gauduchon connection being "K\"ahler-like", namely, satisfying the same symmetries for curvature as the Levi Civita and Chern connections. In particular, we investigate $6$-dimensional solvmanifolds with invariant complex ... More
Non-Kaehler Heterotic String Compactifications with non-zero fluxes and constant dilatonApr 10 2008Jun 17 2008We construct new explicit compact supersymmetric valid solutions with non-zero field strength, non-flat instanton and constant dilaton to the heterotic equations of motion in dimension six. We present balanced Hermitian structures on compact nilmanifolds ... More
Symplectic harmonicity and generalized coeffective cohomologiesApr 27 2014Jul 17 2018Relations between the symplectically harmonic cohomology and the coeffective cohomology of a symplectic manifold are obtained. This is achieved through a generalization of the latter, which in addition allows us to provide a coeffective version of the ... More
Non-nilpotent complex geometry of nilmanifolds and heterotic supersymmetryDec 27 2009Dec 04 2012We classify non-nilpotent complex structures on 6-nilmanifolds and their associated invariant balanced metrics. As an application we find a large family of solutions of the heterotic supersymmetry equations with non-zero flux, non-flat instanton and constant ... More
Balanced Hermitian geometry on 6-dimensional nilmanifoldsApr 28 2011Dec 04 2012The invariant balanced Hermitian geometry of nilmanifolds of dimension 6 is described. We prove that the holonomy group of the associated Bismut connection reduces to a proper subgroup of SU(3) if and only if the complex structure is abelian. As an application ... More
Symplectic harmonicity and generalized coeffective cohomologiesApr 27 2014Relations between the symplectically harmonic and the coeffective cohomologies of a symplectic manifold are given. This is achieved through a generalization of the latter, which in addition provides a coeffective version of the filtered cohomologies. ... More
On the Bott-Chern cohomology and balanced Hermitian nilmanifoldsOct 01 2012The Bott-Chern cohomology of 6-dimensional nilmanifolds endowed with invariant complex structure is studied with special attention to the cases when balanced or strongly Gauduchon Hermitian metrics exist. We consider complex invariants introduced by Angella ... More
Compact supersymmetric solutions of the heterotic equations of motion in dimensions 7 and 8Jun 26 2008Nov 16 2008We construct explicit compact solutions with non-zero field strength, non-flat instanton and constant dilaton to the heterotic string equations in dimensions seven and eight. We present a quadratic condition on the curvature which is necessary and sufficient ... More
Strong Kaehler with torsion structures from almost contact manifoldsSep 22 2009Nov 18 2010For an almost contact metric manifold $N$, we find conditions for which either the total space of an $S^1$-bundle over $N$ or the Riemannian cone over $N$ admits a strong K\"ahler with torsion (SKT) structure. In this way we construct new 6-dimensional ... More
Balanced Hermitian metrics from SU(2)-structuresAug 08 2008We study the intrinsic geometrical structure of hypersurfaces in 6-manifolds carrying a balanced Hermitian SU(3)-structure, which we call {\em balanced} SU(2)-{\em structures}. We provide conditions which imply that such a 5-manifold can be isometrically ... More
Compact supersymmetric solutions of the heterotic equations of motion in dimension 5Nov 13 2008Jun 09 2009We construct explicit compact supersymmetric solutions with non-zero field strength, non-flat instanton and constant dilaton to the heterotic string equations in dimension five. We present a quadratic condition on the curvature which is necessary and ... More
Invariant complex structures on 6-nilmanifolds: classification, Frölicher spectral sequence and special Hermitian metricsNov 24 2011Oct 10 2014We classify invariant complex structures on 6-dimensional nilmanifolds up to equivalence. As an application, the behaviour of the associated Fr\"olicher sequence is studied as well as its relation to the existence of strongly Gauduchon metrics. We also ... More
Complex structures of splitting typeJul 13 2015Apr 27 2016We study the six-dimensional solvmanifolds that admit complex structures of splitting type classifying the underlying solvable Lie algebras. In particular, many complex structures of this type exist on the Nakamura manifold $X$, and they allow us to construct ... More
Invariant solutions to the Strominger system and the heterotic equations of motion on solvmanifoldsApr 11 2016We present compact solvmanifolds that provide many invariant solutions to the Strominger system with respect to a 2-parameter family of metric connections $\nabla^{\varepsilon,\rho}$. The family $\nabla^{\varepsilon,\rho}$ is a natural extension of the ... More
The modular class of a Dirac mapJan 26 2016In this paper we study the modular classes of Dirac manifolds and of Dirac maps, and we discuss their basic properties. We apply these results to explain the relationship between the modular classes of the various structures involved in the reduction ... More
Hyperbolicity and Types of Shadowing for C1 Generic Vector FieldsMay 13 2013Mar 04 2016We study various types of shadowing properties and their implication for C1 generic vector fields. We show that, generically, any of the following three hypotheses implies that an isolated set is topologically transitive and hyperbolic: (i) the set is ... More
Conservative flows with various types of shadowingJun 11 2013Jul 29 2014In the present paper we study the C1-robustness of the three properties: average shadowing, asymptotic average shadowing and limit shadowing within two classes of conservative flows: the incompressible and the Hamiltonian ones. We obtain that the first ... More
Sequences of Open Riemannian Manifolds with BoundaryJan 17 2013Jun 19 2013We consider sequences of open Riemannian manifolds with boundary that have no regularity conditions on the boundary. To define a reasonable notion of a limit of such a sequence, we examine "$\delta$ inner regions" which avoid the boundary by a distance ... More
On the Sormani-Wenger Intrinsic Flat Convergence of Alexandrov SpacesNov 25 2014We study noncollapsing sequences of integral current spaces $(X_j,d_j,T_j)$ with no boundary such that $(X_j,d_j)$ are Alexandrov spaces with nonnegative curvature and diameter uniformly bounded from above and such that the integral current structure ... More
Inflationary signatures of single-field models beyond slow-rollFeb 20 2012Jun 04 2012If the expansion of the early Universe was not close to de Sitter, the statistical imprints of the primordial density perturbation on the cosmic microwave background can be quite different from those derived in slow-roll inflation. In this paper we study ... More
Deep Watershed Transform for Instance SegmentationNov 24 2016Most contemporary approaches to instance segmentation use complex pipelines involving conditional random fields, recurrent neural networks, object proposals, or template matching schemes. In our paper, we present a simple yet powerful end-to-end convolutional ... More
Fatou-Bieberbach domains as basins of attraction of automorphisms tangent to the identityJul 12 2009We prove that there exists an automorphism of C^2 tangent to the identity with a domain of attraction to the origin, biholomorphic to the origin, along a degenerate characteristic direction.
Osculating properties of decomposable scrollsNov 23 2007Osculating spaces of decomposable scrolls (of any genus and not necessarily normal)are studied and their inflectional loci are related to those of their generating curves by using systematically an idea introduced by Piene and Sacchiero in the setting ... More
Selection rules for quasiparticle interference with internal nonsymmorphic symmetriesDec 26 2017Dec 10 2018We study how nonsymmorphic symmetries that commute with lattice translations are reflected in the quasiparticle interference (QPI) maps measured by scanning tunneling microscopy (STM). QPI maps, which result from scattering of Bloch states off impurities, ... More
Constructions of MDS convolutional codes using superregular matricesMar 26 2019Maximum distance separable convolutional codes are the codes that present best performance in error correction for fixed rate and degree. In this paper we present conditions on the coefficients of the entries of the generator matrices of a convolutional ... More
An efficient asymptotic approach for testing monotone proportions assuming an underlying logit based order dose-response modelFeb 26 2014When an underlying logit based order dose-response model is considered with small or moderate sample sizes, the Cochran-Armitage (CA) test represents the most efficient test in the framework of the test-statistics applied with asymptotic distributions ... More
Hom-configurations and noncrossing partitionsDec 06 2010Let Q be a Dynkin quiver. The bounded derived category of the path algebra of Q has an autoequivalence given by the composition of the Auslander-Reiten translate and the square of the shift functor. We study maximal Hom-free sets in the corresponding ... More
Magnetorotational instability in stratified, weakly ionised accretion discsJul 14 2003We present a linear analysis of the vertical structure and growth of the magnetorotational instability in stratified, weakly ionised accretion discs, such as protostellar and quiescent dwarf novae systems. The method includes the effects of the magnetic ... More
Studies of Dimension-Six EFT effects in Vector Boson ScatteringSep 11 2018Oct 04 2018We discuss the implications of dimension-six operators of the Effective Field Theory (EFT) framework in the study of Vector Boson Scattering (VBS) in the $pp \to Z Z j j $ channel. We show that operators of dimension-six should not be neglected in favour ... More
Aspects of inflation and the very early universeSep 20 2013Until recently our knowledge of the primordial curvature perturbation was relatively modest. Ever since COBE delivered its map of data we know the scalar spectrum of primordial perturbations is approximately flat, with the power being only slightly stronger ... More
Asymptotic behavior of grafting raysSep 05 2007Sep 20 2007In this paper we study the convergence behavior of grafting rays to the Thurston boundary of Teichmuller space. When the grafting is done along a weighted system of simple closed curves or along a maximal uniquely ergodic lamination this behavior is the ... More
Remarks on Automorphisms of $\mathbb{C}^* \times \mathbb{C}^*$ and their basinsSep 12 2008We study basins of attraction of automorphisms of $\CC^2$ tangent to the identity that fix both axes. Our main result is that, if a well known conjecture about automorphisms of $\CC^*\times\CC^*$ holds, then there are no basins of attraction associated ... More
Automatic Evaluation of Neural Personality-based ChatbotsSep 30 2018Stylistic variation is critical to render the utterances generated by conversational agents natural and engaging. In this paper, we focus on sequence-to-sequence models for open-domain dialogue response generation and propose a new method to evaluate ... More
Splitting the hinge mode of higher-order topological insulatorsJul 11 2018Mar 01 2019The surface of a higher order topological insulator (HOTI) comprises a two-dimensional topological insulator (TI) with broken inversion symmetry, whose mass is determined by the microscopic details of the surface such as surface potentials and termination. ... More
Depth of segments and circles through points enclosing many points: a noteMar 07 2008Neumann-Lara and Urrutia showed in 1985 that in any set of n points in the plane in general positionthere is always a pair of points such that any circle through them contains at least (n-2)/60 points. In a series of papers, this result was subsequently ... More
Mutations of simple-minded systems in Calabi-Yau categories generated by a spherical objectDec 31 2015In this article, we give a definition and a classification of 'higher' simple-minded systems in triangulated categories generated by spherical objects with negative Calabi-Yau dimension. We also study mutations of this class of objects and that of 'higher' ... More
Proper Hamiltonian Cycles in Edge-Colored MultigraphsNov 19 2014Feb 13 2017A $c$-edge-colored multigraph has each edge colored with one of the $c$ available colors and no two parallel edges have the same color. A proper Hamiltonian cycle is a cycle containing all the vertices of the multigraph such that no two adjacent edges ... More
Decoding the bispectrum of single-field inflationAug 18 2011Oct 24 2011Galileon fields arise naturally from the decoupling limit of massive gravities, and possess special self-interactions which are protected by a spacetime generalization of Galilean symmetry. We briefly revisit the inflationary phenomenology of Galileon ... More
A polynomial skew-product with a wandering Fatou-diskMay 06 2014Little is known about the existence of wandering Fatou components for rational maps in two complex variables. In 2003 Lilov proved the non-existence of wandering Fatou components for polynomial skew-products in the neighborhood of an invariant super-attracting ... More
Simple-minded systems and reduction for negative Calabi-Yau triangulated categoriesAug 07 2018We develop the basic properties of $w$-simple-minded systems in $(-w)$-Calabi-Yau triangulated categories for $w \geq 1$. The main result is a reduction technique for negative Calabi-Yau triangulated categories. We show that the theory of simple-minded ... More
Torsion pairs in a triangulated category generated by a spherical objectApr 17 2014Nov 06 2015We extend Ng's characterisation of torsion pairs in the 2-Calabi-Yau triangulated category generated by a 2-spherical object to the characterisation of torsion pairs in the w-Calabi-Yau triangulated category, $T_w$, generated by a w-spherical object for ... More
Proper Hamiltonian Cycles in Edge-Colored MultigraphsNov 19 2014Jul 27 2016A $c$-edge-colored multigraph has each edge colored with one of the $c$ available colors and no two parallel edges have the same color. A proper Hamiltonian cycle is a cycle containing all the vertices of the multigraph such that no two adjacent edges ... More
Mild bounds on bigravity from primordial gravitational wavesMay 03 2015If the amplitude of primordial gravitational waves is measured in the near-future, what could it tell us about bigravity? To address this question, we study massive bigravity theories by focusing on a region in parameter space which is safe from known ... More
A geometric model for the module category of a gentle algebraMar 15 2018In this article, gentle algebras are realised as tiling algebras, which are associated to partial triangulations of unpunctured surfaces with marked points on the boundary. This notion of tiling algebras generalise the notion of Jacobian algebras of triangulations ... More
Quantum quenches during inflationNov 30 2016We propose a new technique to study fast transitions during inflation, by studying the dynamics of quantum quenches in an $O(N)$ scalar field theory in de Sitter spacetime. We compute the time evolution of the system using a non-perturbative large-$N$ ... More
One-Loop counterterms in first order quantum gravityJun 08 2017Jan 15 2018One-loop counterterms are computed in first order formalism for the Einstein-Hilbert action using the background field method and the heat kernel technique. The obtained result coincides with the result found by Hooft and Veltman in second order formalism. ... More
Fully Connected Deep Structured NetworksMar 09 2015Convolutional neural networks with many layers have recently been shown to achieve excellent results on many high-level tasks such as image classification, object detection and more recently also semantic segmentation. Particularly for semantic segmentation, ... More
Quantum quenches during inflationNov 30 2016Feb 22 2017We propose a new technique to study fast transitions during inflation, by studying the dynamics of quantum quenches in an $O(N)$ scalar field theory in de Sitter spacetime. We compute the time evolution of the system using a non-perturbative large-$N$ ... More
A generalized tetrahedral propertySep 18 2017Dec 23 2018We present examples of metric spaces that are not Riemannian manifolds nor dimensionally homogeneous that satisfy the Tetrahedral Property. In spite of that, Euclidean cones over metric spaces with small diameter do not satisfy this property. We extend ... More
Scale-dependent bias from multiple-field inflationMar 24 2013May 29 2013We provide a formula for the scaling behaviour of the inflationary bispectrum in the 'squeezed' limit where one momentum becomes much smaller than the other two. This determines the scaling of the halo bias at low wavenumber and will be an important observable ... More
Jacobi-Nijenhuis algebroids and their modular classesJun 11 2007Sep 26 2007Jacobi-Nijenhuis algebroids are defined as a natural generalization of Poisson-Nijenhuis algebroids, in the case where there exists a Nijenhuis operator on a Jacobi algebroid which is compatible with it. We study modular classes of Jacobi and Jacobi-Nijenhuis ... More
A Prototype for the Cherenkov Telescope Array Pipelines Framework: Modular Efficiency Simple System (MESS)Sep 04 2015Sep 07 2015The Cherenkov Telescope Array (CTA) is a ground-based $\gamma$-ray observatory that will observe the full sky in the energy range from 20 GeV to 100 TeV from facilities in both hemispheres. It is proposed to consist of more than 100 telescopes, producing ... More
A new LES model derived from generalized Navier-Stokes equations with nonlinear viscositySep 15 2015Large Eddy Simulation (LES) is a very useful tool when simulating turbulent flows if we are only interested in its "larger" scales. One of the possible ways to derive the LES equations is to apply a filter operator to the Navier-Stokes equations, obtaining ... More
Short-Term Meaning Shift: A Distributional ExplorationSep 10 2018Apr 03 2019We present the first exploration of meaning shift over short periods of time in online communities using distributional representations. We create a small annotated dataset and use it to assess the performance of a standard model for meaning shift detection ... More
PIXOR: Real-time 3D Object Detection from Point CloudsFeb 17 2019Feb 28 2019We address the problem of real-time 3D object detection from point clouds in the context of autonomous driving. Computation speed is critical as detection is a necessary component for safety. Existing approaches are, however, expensive in computation ... More
Enhanced (p)reheating in DBI InflationAug 28 2009We study preheating in DBI hybrid inflation. Preheating occurs since the matter fields are non-minimally coupled to the inflaton. Despite the coupling being small, preheating happens as a narrow parametric resonance in which matter fields and inflaton ... More
Why does the effective field theory of inflation work?Nov 04 2013May 16 2014The effective field theory (EFT) of inflation has become the preferred method for computing cosmological correlation functions of the curvature fluctuation, $\zeta$. It makes explicit use of the soft breaking of time diffeomorphisms by the inflationary ... More
Bayesian Mixed Effect Sparse Tensor Response Regression Model with Joint Estimation of Activation and ConnectivityMar 30 2019Brain activation and connectivity analyses in task-based functional magnetic resonance imaging (fMRI) experiments with multiple subjects are currently at the forefront of data-driven neuroscience. In such experiments, interest often lies in understanding ... More
Classification of interacting fermionic phases by dimensional reductionJan 07 2016We present a dimensional reduction argument to derive the classification of fermionic symmetry protected topological phases in the presence of interactions. The dimensional reduction proceeds by relating the topological character of a $d$-dimensional ... More
Conformal invariance versus Weyl invarianceMar 13 2019The most general quadratic lagrangian describing spin 2 particles in flat spacetime and containing operators of dimension up to 6 is carefully analyzed, determining the precise conditions for it to be invariant under linearized (transverse) diffeomorphisms, ... More
Column distance of convolutional codes over ZprJul 31 2017Rosenthal et al. introduced and thoroughly studied the notion of Maximum Distance Profile (MDP) convolutional codes over (non-binary) finite fields refining the classical notion of optimum distance profile, see for instance [18, p.164]. These codes have ... More
On fractional p-Laplacian problems with weightApr 22 2014We investigate the existence of nonnegative solutions for a nonlinear problem involving the fractional p-Laplacian operator. The problem is set on a unbounded domain, and compactness issues have to be handled.
Unified description of the classical Hall viscosityMar 13 2019In absence of time-reversal symmetry, viscous electron flow hosts a number of interesting phenomena, of which we focus here on the Hall viscosity. Taking a step beyond the hydrodynamic definition of the Hall viscosity, we derive a generalized relation ... More
PIXOR: Real-time 3D Object Detection from Point CloudsFeb 17 2019We address the problem of real-time 3D object detection from point clouds in the context of autonomous driving. Computation speed is critical as detection is a necessary component for safety. Existing approaches are, however, expensive in computation ... More
Dynamics of shadow system of a singular Gierer-Meinhardt system on an evolving domainMar 24 2019The main purpose of the current paper is to contribute towards the comprehension of the dynamics of the shadow system of a singular Gierer-Meinhardt model on an isotropically evolving domain. In the case where the inhibitor's response to the activator's ... More
Variability Analysis of Complex Networks Measures based on Stochastic DistancesJul 29 2014Complex networks can model the structure and dynamics of different types of systems. It has been shown that they are characterized by a set of measures. In this work, we evaluate the variability of complex networks measures face to perturbations and, ... More
Riding on irrelevant operatorsMay 20 2014Nov 11 2014We investigate the stability of a class of derivative theories known as $P(X)$ and Galileons against corrections generated by quantum effects. We use an exact renormalisation group approach to argue that these theories are stable under quantum corrections ... More
Inversion of a mapping associated with the Aomoto-Forrester systemFeb 06 2013Dec 05 2013This article is devoted to the study of a general class of Hamiltonian systems which extends the Calogero systems with external quadratic potential associated to any root system. The interest for such a class comes from a previous article of Aomoto and ... More
Inflectional loci of scrollsDec 14 2006Mar 28 2007Let $X\subset \mathbb P^N$ be a scroll over a smooth curve $C$ and let $\L=\mathcal O_{\mathbb P^N}(1)|_X$ denote the hyperplane bundle. The special geometry of $X$ implies that some sheaves related to the principal part bundles of $\L$ are locally free. ... More
Few-Shot Learning Through an Information Retrieval LensJul 09 2017Nov 14 2017Few-shot learning refers to understanding new concepts from only a few examples. We propose an information retrieval-inspired approach for this problem that is motivated by the increased importance of maximally leveraging all the available information ... More
On the chiral covariant approach to $ρρ$ scatteringDec 23 2016Nov 29 2017We examine in detail a recent work (D.~G\"ulmez, U.-G.~Mei\ss ner and J.~A.~Oller, Eur. Phys. J. C 77:460 (2017)), where improvements to make $\rho\rho$ scattering relativistically covariant are made. The paper has the remarkable conclusion that the $J=2$ ... More
Soccer Field Localization from a Single ImageApr 10 2016In this work, we propose a novel way of efficiently localizing a soccer field from a single broadcast image of the game. Related work in this area relies on manually annotating a few key frames and extending the localization to similar images, or installing ... More
Wald type and Phi-divergence based test-statistics for isotonic binomial proportionsFeb 26 2014In this paper new test statistics are introduced and studied for the important problem of testing hypothesis that involves inequality constraint on proportions when the sample comes from independent binomial random variables: Wald type and phi-divergence ... More
Analyzing Tag Distributions in Folksonomies for Resource ClassificationFeb 23 2012Recent research has shown the usefulness of social tags as a data source to feed resource classification. Little is known about the effect of settings on folksonomies created on social tagging systems. In this work, we consider the settings of social ... More
Radiative decays of the Y(3940), Z(3930) and the X(4160) as dynamically generated resonancesOct 04 2010We study the radiative decay properties of the charmonium-like X, Y and Z mesons generated dynamically from vector meson-vector meson interaction in the framework of a unitarized hidden-gauge formalism. In the present work we calculate the one- and two-photon ... More
Analysing the potential of seq-to-seq models for incremental interpretation in task-oriented dialogueAug 28 2018We investigate how encoder-decoder models trained on a synthetic dataset of task-oriented dialogues process disfluencies, such as hesitations and self-corrections. We find that, contrary to earlier results, disfluencies have very little impact on the ... More
On MDS convolutional Codes over $\mathbb Z_{p^r}$Jan 18 2016Maximum Distance Separable (MDS) convolutional codes are cha- racterized through the property that the free distance meets the generalized Singleton bound. The existence of free MDS convolutional codes over Z p r was recently discovered in [26] via the ... More
FollowMe: Efficient Online Min-Cost Flow Tracking with Bounded Memory and ComputationJul 23 2014Dec 25 2014One of the most popular approaches to multi-target tracking is tracking-by-detection. Current min-cost flow algorithms which solve the data association problem optimally have three main drawbacks: they are computationally expensive, they assume that the ... More
The δN formula is the dynamical renormalization groupOct 29 2012Oct 30 2013We derive the 'separate universe' method for the inflationary bispectrum, beginning directly from a field-theory calculation. We work to tree-level in quantum effects but to all orders in the slow-roll expansion, with masses accommodated perturbatively. ... More
Large slow-roll corrections to the bispectrum of noncanonical inflationMar 21 2011Jul 27 2011Nongaussian statistics are a powerful discriminant between inflationary models, particularly those with noncanonical kinetic terms. Focusing on theories where the Lagrangian is an arbitrary Lorentz-invariant function of a scalar field and its first derivatives, ... More
The effects of a fast-turning trajectory in multiple-field inflationJan 23 2014Aug 27 2014The latest results from PLANCK impose strong constraints on features in the spectrum of the curvature perturbations from inflation. We analyse the possibility of particle production induced by sharp turns of the trajectory in field space in inflation ... More
Asymptotically linear fractional Schrodinger equationsJan 09 2014By exploiting a variational technique based upon projecting over the Pohozaev manifold, we prove existence of positive solutions for a class of nonlinear fractional Schrodinger equations having a nonhomogenous nonautonomous asymptotically linear nonlinearity. ... More
A Prototype Data Format for the Cherenkov Telescope Array: Regions Of Interest (ROI)Sep 04 2015The Cherenkov Telescope Array (CTA) is a ground-based $\gamma$-ray observatory that will observe the full sky in the energy range from 20 GeV to 100 TeV from facilities in both hemispheres. It is proposed to consist of more than 100 telescopes and the ... More
Dimensional hierarchy of fermionic interacting topological phasesJan 07 2016Nov 14 2016We present a dimensional reduction argument to derive the classification reduction of fermionic symmetry protected topological phases in the presence of interactions. The dimensional reduction proceeds by relating the topological character of a $d$-dimensional ... More
PIXOR: Real-time 3D Object Detection from Point CloudsFeb 17 2019Mar 02 2019We address the problem of real-time 3D object detection from point clouds in the context of autonomous driving. Computation speed is critical as detection is a necessary component for safety. Existing approaches are, however, expensive in computation ... More
Endomorphism algebras for a class of negative Calabi-Yau categoriesFeb 06 2016Feb 16 2016We consider an orbit category of the bounded derived category of a path algebra of type A_n which can be viewed as a -(m+1)-cluster category, for m >= 1. In particular, we give a characterisation of those maximal m-rigid objects whose endomorphism algebras ... More
The ascending central series of nilpotent Lie algebras with complex structureAug 16 2017We obtain several restrictions on the terms of the ascending central series of a nilpotent Lie algebra $\mathfrak g$ under the presence of a complex structure $J$. In particular, we find a bound for the dimension of the center of $\mathfrak g$ when it ... More
BRDF Estimation of Complex Materials with Nested LearningNov 22 2018The estimation of the optical properties of a material from RGB-images is an important but extremely ill-posed problem in Computer Graphics. While recent works have successfully approached this problem even from just a single photograph, significant simplifications ... More
Understanding quality control of hard metals in industry -- A quantum mechanics approachFeb 21 2019For many decades, the magnetic saturation of, e.g. hard metals (HM) such as WC-Co-based cemented carbides, has been used as process and quality control in industry to ensure consistency of product properties. In an urge of replacing cobalt as a binder ... More
Extraction of isoscalar $ππ$ phase-shifts from lattice QCDMar 07 2018We conduct a two-flavor ($N_f=2$) lattice QCD calculation of the elastic phase-shifts for pion-pion scattering in the scalar, isoscalar channel (the $\sigma$-meson). The calculation is performed for two quark masses corresponding to a pion mass of $315\text{ ... More
Physical content of Quadratic GravityFeb 16 2018Jul 12 2018We have recently undergone an analysis of gravitational theories as defined in first order formalism, where the metric and the connection are treated as independent fields. The physical meaning of the connection field has historically been somewhat elusive. ... More
A survey on the Convergence of Manifolds with BoundaryOct 02 2013This survey reviews precompactness theorems for classes of Riemannian manifolds with boundary. We begin with the works of Kodani, Anderson-Katsuda-Kurylev-Lassas-Taylor and Wong. We then present new results of Knox and the author with Sormani.
Inflationary perturbation theory is geometrical optics in phase spaceMar 12 2012Sep 07 2012A pressing problem in comparing inflationary models with observation is the accurate calculation of correlation functions. One approach is to evolve them using ordinary differential equations ("transport equations"), analogous to the Schwinger-Dyson hierarchy ... More
Preheating in Dirac-Born-Infeld inflationMay 13 2010Sep 10 2010We study how the universe reheats following an era of chaotic Dirac-Born-Infeld inflation, and compare the rate of particle production with that in models based on canonical kinetic terms. Particle production occurs through non-perturbative resonances ... More
Superconducting properties and hydrostatic pressure effect on ABi3 (A=Ba,Sr) single crystalsJul 12 2016We report on the crystal growth and characterization of ABi3 (A=Ba,Sr) superconductors. Single crystals of both compounds were grown by the self-flux technique. BaBi3 crystallized in a tetragonal structure with space group P4/mmm and SrBi3 in a cubic ... More
Double screeningApr 01 2016Attempts to modify gravity in the infrared typically require a screening mechanism to ensure consistency with local tests of gravity. These screening mechanisms fit into three broad classes; we investigate theories which are capable of exhibiting more ... More