Results for "Miguel Orszag"

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Geometric quantum discord with Bures distance: the qubit caseAug 22 2013Dec 23 2013The minimal Bures distance of a quantum state of a bipartite system AB to the set of classical states for subsystem A defines a geometric measure of quantum discord. When A is a qubit, we show that this geometric quantum discord is given in terms of the ... More
Decoherence versus disentanglement for two qubits in a squeezed bathJan 09 2008We study the relation between the sudden death and revival of the entanglement of two qubits in a common squeezed reservoir, and the normal decoherence, by getting closer to the Decoherence Free Subspace and calculating the effect on the death and revival ... More
Geometric quantum discord with Bures distanceApr 11 2013Dec 20 2013We define a new measure of quantum correlations in bipartite quantum systems given by the Bures distance of the system state to the set of classical states with respect to one subsystem, that is, to the states with zero quantum discord. Our measure is ... More
Phonon maser stimulated by spin post-selectionFeb 08 2019In a sequence of single spins interacting dispersively with a mechanical oscillator, and using the micromaser model with random injection, we show that after an appropriate post-selection of each spin, a phonon laser analog with Poisson statistics is ... More
Determination of the maximum Global Quantum Discord via measurements of excitations in a cavity QED networkJan 13 2014Multipartite Quantum Correlations is one of the most relevant indicator of the quantumness of a system in many body systems. This remarkable feature is in general difficult to characterize and the known definitions are hard to measure. Besides the efforts ... More
Propagation and Distribution of Quantum Correlations in a Cavity QED NetworkJun 05 2013We study the propagation and distribution of quantum correlations through two chains of atoms inside cavities joined by optical fibers. We consider an effective Hamiltonian for the system and cavity losses, in the dressed atom picture, using the Generalized ... More
Thermally generated long-lived quantum correlations for two atoms trapped in fiber-coupled cavitiesNov 22 2011Apr 25 2012A theoretical model for driving a two qubit system to a stable long-lived entanglement is discussed. The entire system is represented by two atoms, initially in ground states and disentangled, each one coupled to a separate cavity with the cavities connected ... More
Generation and protection of Maximally Entangled State between many modes in an optical network with dissipationOct 03 2016We present a three-cavity network model with two modes in each cavity and a non-linear medium that generates a Kerr type interaction via both self-phase and cross-phase modulation processes. We have two main goals. The first one is to generate a multipartite ... More
Thermal effects on the sudden changes and freezing of correlations between remote atoms in cavity QED networkFeb 10 2014We investigate the thermal effects on the sudden changes and freezing of the quantum and classical correlations of remote qubits in a cavity quantum electrodynamics (CQED) network with losses. We find that the detrimental effect of the thermal reservoirs ... More
Selftrapping triggered by losses in cavity QEDDec 23 2014In a coupled cavity QED network model, we study the transition from a localized super fluid like state to a delocalized Mott insulator like state, triggered by losses. Without cavity losses, the transition never takes place. Further, if one measures the ... More
The power of a control qubit in weak measurementsSep 28 2016In the late 80s, a curious effect suggested by Aharanov, Albert and Vaidman opened up new vistas regarding quantum measurements on weakly coupled systems. There, a combination of a "weak" finite interaction together with a "strong" post-selection measurement ... More
Harnessing synthetic gauge fields for maximally entangled state generationJan 21 2014We study the generation of entanglement between two species of neutral cold atoms living on an optical ring lattice, where each group of particles can be described by a $d$-dimensional Hilbert space (qu$d$it). Synthetic magnetic fields are exploited to ... More
Quantum Correlations in Cavity QED NetworksJul 21 2014We present a Review of the dynamical features such as generation, propagation, distribution, sudden transition and freezing of the various quantum correlation measures, as Concurrence, Entanglement of Formation, Quantum Discord, as well their geometrical ... More
Macroscopic non-classical state preparation via post-selectionDec 09 2016Dec 04 2017Macroscopic mechanical qubits are fundamental both to test the classical-quantum boundary and present suitable candidates for quantum information processing. Motivated by these, we propose a feasible probabilistic scheme to generate an on-demand mechanical ... More
Toward a finite-dimensional formulation of Quantum Field TheoryMay 04 1998Rules of quantization and equations of motion for a finite-dimensional formulation of Quantum Field Theory are proposed which fulfill the following properties: a) both the rules of quantization and the equations of motion are covariant; b) the equations ... More
From entanglement renormalisation to the disentanglement of quantum double modelsDec 26 2010Aug 16 2011We describe how the entanglement renormalisation approach to topological lattice systems leads to a general procedure for treating the whole spectrum of these models, in which the Hamiltonian is gradually simplified along a parallel simplification of ... More
Technical notes on a 2-d lattice O(N) model problemSep 28 2004Jan 18 2005This paper provides a technical companion to M. Aguado and E. Seiler, hep-lat/0406041, in which the fate of perturbation theory in the thermodynamic limit is discussed for the O(N) model on a 2d lattice and different boundary conditions. The techniques ... More
The Alternative Daugavet Property of $C^*$-algebras and $JB^*$-triplesNov 24 2004A Banach space $X$ is said to have the alternative Daugavet property if for every (bounded and linear) rank-one operator $T:X\longrightarrow X$ there exists a modulus one scalar $\omega$ such that $\|Id + \omega T\|= 1 + \|T\|$. We give geometric characterizations ... More
Kahler geometry of toric varieties and extremal metricsNov 19 1997Recently Guillemin gave an explicit combinatorial way of constructing "toric" Kahler metrics on (symplectic) toric varieties, using only data on the moment polytope. In this paper, differential geometric properties of these metrics are investigated using ... More
On the completeness of trajectories for some mechanical systemsMar 25 2013Sep 26 2013The classical tools which ensure the completeness of vector fields and second order differential equations for mechanical systems are revisited. Possible extensions in three directions are discussed: infinite dimensional Banach and Hilbert manifolds, ... More
Some remarks on Causality Theory and Variational Methods in Lorentzian manifoldsDec 04 2007Feb 29 2008In this conference published in 1997 some problems on the geodesics of a Lorentzian manifold concerning causality and infinite-dimensional variational methods, are pointed out. Even though a big progress on many of these questions have been carried out ... More
Fibre bundles, connections, general relativity, and Einstein-Cartan theoryOct 05 2011We present in the most natural way, that is, in the context of the theory of vector and principal bundles and connections in them, fundamental geometrical concepts related to General Relativity and one of its extensions, the Einstein-Cartan theory.
Charge Conjugation in the Galilean LimitMar 17 2006Strictly working in the framework of the nonrelativistic quantum mechanics of a spin 1/2 particle coupled to an external electromagnetic field, we show, by explicit construction, the existence of a charge conjugation operator matrix which defines the ... More
On the foundations and necessity of classical gauge invarianceMar 10 2008We argue that, ideally, the ways to measure magnitudes in non-quantum theories of physics (spacetime, field theory), limit drastically their possible mathematical models. In particular, gauge invariance in the Yang-Mills framework, is a necessity of our ... More
Causal boundaries and holography on wave type spacetimesDec 01 2008Mar 14 2009The notion of a causal boundary for a spacetime has been a controversial topic during the last three decades. Moreover, recently the role of the boundary in the AdS/CFT correspondence for plane waves, have stimulated its redefinition with some possible ... More
What can(not) be measured with ton-scale dark matter direct detection experimentsJun 03 2011Oct 31 2011Direct searches for dark matter have prompted in recent years a great deal of excitement within the astroparticle physics community, but the compatibility between signal claims and null results of different experiments is far from being a settled issue. ... More
Can our number system be improved?Dec 14 2001Our number system is a magnificent tool. But it is far from perfect. Can it be improved? In this paper some possibilities are discussed, including the use of a different base or directed (negative as well as positive) numerals. We also put forward some ... More
The like-sign dimuon asymmetry and New PhysicsNov 14 2014The measurement by the D0 collaboration of a large like-sign dimuon asymmetry deviates significantly from Standard Model expectations. New Physics may be invoked to account for such a deviation. We analyse how generic extensions of the Standard Model ... More
On different definitions of numerical rangeFeb 25 2015We study the relation between the intrinsic and the spatial numerical ranges with the recently introduced "approximated" spatial numerical range. As main result, we show that the intrinsic numerical range always coincides with the convex hull of the approximated ... More
Rhythms of the collective brain: Metastable synchronization and cross-scale interactions in connected multitudesNov 21 2016Collective social events operate at many levels of organization -- from individuals to crowds -- presenting a variety of temporal and spatial scales of activity, whose causal interactions challenge our understanding of social systems. Large data sets ... More
On the Geometry of Static SpacetimesJun 16 2004Jun 26 2004We review geometrical properties of a static spacetime $(M,g)$, including geodesic completeness, causality, standard splittings, compact $M$, closed geodesics and geodesic connectedness. We pay special attention to the critical quadratic behavior at infinity ... More
Finding long simple paths in a weighted digraph using pseudo-topological orderingsSep 23 2016Given a weighted digraph D, finding the longest simple path is well known to be NP-hard. Furthermore, even giving an approximation algorithm is known to be NP-hard. In this paper we describe an efficient heuristic algorithm for finding long simple paths, ... More
Smoothing of ribbons over curvesFeb 05 2003Apr 04 2005We prove that ribbons, i.e. double structures associated with a line bundle $\SE$ over its reduced support, a smooth irreducible projective curve of arbitrary genus, are smoothable if their arithmetic genus is greater than or equal to $3 $ and the support ... More
Character varieties for real formsOct 17 2016Oct 12 2017Let $\Gamma$ be a finitely generated group and $G$ a real form of $\mathrm{SL}_n(\mathbb{C})$. We propose a definition for the $G$-character variety of $\Gamma$ as a subset of the $\mathrm{SL}_n(\mathbb{C})$-character variety of $\Gamma$. We consider ... More
Generalized symmetries and invariant matter couplings in two-dimensional dilaton gravityFeb 20 1997Apr 04 1997New features of the generalized symmetries of generic two-dimensional dilaton models of gravity are presented and invariant gravity-matter couplings are introduced. We show that there is a continuum set of Noether symmetries, which contains half a de ... More
Kahler geometry of toric manifolds in symplectic coordinatesApr 19 2000A theorem of Delzant states that any symplectic manifold $(M,\om)$ of dimension $2n$, equipped with an effective Hamiltonian action of the standard $n$-torus $\T^n = \R^{n}/2\pi\Z^n$, is a smooth projective toric variety completely determined (as a Hamiltonian ... More
Kahler metrics on toric orbifoldsMay 14 2001A theorem of E.Lerman and S.Tolman, generalizing a result of T.Delzant, states that compact symplectic toric orbifolds are classified by their moment polytopes, together with a positive integer label attached to each of their facets. In this paper we ... More
A note on stability and Cauchy time functionsApr 21 2013May 13 2013Since the solution of the so-called folk problems of smoothability, there has been a special interest in the properties of classical time and volume functions of spacetimes. Here we supply some information that complements the one provided in arXiv:1108.5120v3 ... More
Causal hierarchy of spacetimes, temporal functions and smoothness of Geroch's splitting. A revisionNov 29 2004Feb 15 2005After the heroic epoch of Causality Theory, problems concerning the smoothability of time functions and Cauchy hypersurfaces remained as unanswered folk questions. Just recently solved, our aim is to discuss the state of the art on this topic, including ... More
Modified Entropic Gravity and CosmologyFeb 06 2012It has been recently proposed that gravity might be an entropic force. Although a well defined fundamental description for such a mechanism is still lacking, it is still possible to address the viability of phenomenological models of entropic-inspired ... More
The group of isometries of a Banach space and dualitySep 22 2008We construct an example of a real Banach space whose group of surjective isometries has no uniformly continuous one-parameter semigroups, but the group of surjective isometries of its dual contains infinitely many of them. Other examples concerning numerical ... More
Exchange Bias Theory: a ReviewJul 05 2001Research on the exchange bias (EB) phenomenon has witnessed a flurry of activity during recent years, which stems from its use in magnetic sensors and as stabilizers in magnetic reading heads. EB was discovered in 1956 but it attracted only limited attention ... More
An A-based cofibrantly generated model categoryMay 08 2014We develop a cofibrantly generated model category structure in the category of topological spaces in which weak equivalences are A-weak equivalences and such that the generalized CW(A)-complexes are cofibrant objects. With this structure the exponential ... More
$L^{2}$-homology for inclusions of von Neumann algebrasMar 24 2014Mar 25 2014In this paper we define $L^{2}$-homology and $L^{2}$-Betti numbers for tracial *-algebras $A$ with respect to a von Neumann subalgebra $B$. When $B$ is reduced to the field of complex numbers we recover the $L^{2}$-Betti numbers of $A$ as defined by A. ... More
Generation of the Single Precision BLAS library for the Parallella platform, with Epiphany co-processor acceleration, using the BLIS frameworkAug 18 2016The Parallella is a hybrid computing platform that came into existence as the result of a Kickstarter project by Adapteva. It is composed of the high performance, energy-efficient, manycore architecture, Epiphany chip (used as co-processor) and one Zynq-7000 ... More
Mass-deformed ABJ and ABJM theory, Meixner-Pollaczek polynomials, and $su(1,1)$ oscillatorsApr 21 2016May 18 2016We give explicit analytical expressions for the partition function of $U(N)_{k}\times U(N+M)_{-k}$ ABJ theory at weak coupling ($k\rightarrow \infty )$ for finite and arbitrary values of $N$ and $M$ (including the ABJM case and its mass-deformed generalization). ... More
Exact solution of Chern-Simons-matter matrix models with characteristic/orthogonal polynomialsJan 23 2016Apr 27 2016We solve for finite $N$ the matrix model of supersymmetric $U(N)$ Chern-Simons theory coupled to $N_{f}$ fundamental and $N_{f}$ anti-fundamental chiral multiplets of $R$-charge $1/2$ and of mass $m$, by identifying it with an average of inverse characteristic ... More
Constraints on a Class of Two-Higgs Doublet Models with tree level FCNCOct 28 2014We analyse a class of two Higgs doublet models where flavour-changing neutral currents (FCNC) are present at tree level in a mixing-suppressed manner. In this class of models, because of a discrete symmetry imposed on the lagrangian, the FCNC couplings ... More
Note on the phase space of asymptotically flat gravity in Ashtekar-Barbero variablesDec 17 2014We describe the canonical phase space of asymptotically flat gravity in Ashtekar-Barbero variables. We show that the Gauss constraint multiplier must fall off slower than previously considered in order to recover ADM phase space. The generators of the ... More
Epic substructures and primitive positive functionsJul 11 2016For $\mathbf{A}\leq\mathbf{B}$ first order structures in a class $\mathcal{K}$, say that $\mathbf{A}$ is an epic substructure of $\mathbf{B}$ in $\mathcal{K}$ if for every $\mathbf{C}\in\mathcal{K}$ and all homomorphisms $g,g^{\prime}:\mathbf{B}\rightarrow\mathbf{C}$, ... More
Forbidden Configurations: Finding the number predicted by the Anstee-Sali Conjecture is NP-hardOct 30 2012Jan 29 2013Let F be a hypergraph and let forb(m,F) denote the maximum number of edges a hypergraph with m vertices can have if it doesn't contain F as a subhypergraph. A conjecture of Anstee and Sali predicts the asymptotic behaviour of forb(m,F) for fixed F. In ... More
On causality and closed geodesics of compact Lorentzian manifolds and static spacetimesFeb 15 2005Some results related to the causality of compact Lorentzian manifolds are proven: (1) any compact Lorentzian manifold which admits a timelike conformal vector field is totally vicious, and (2) a compact Lorentzian manifold covered regularly by a globally ... More
Finsler metrics and relativistic spacetimesNov 19 2013Sep 15 2014Recent links between Finsler Geometry and the geometry of spacetimes are briefly revisited, and prospective ideas and results are explained. Special attention is paid to geometric problems with a direct motivation in Relativity and other parts of Physics. ... More
A note on the existence of standard splittings for conformally stationary spacetimesJun 04 2008Oct 16 2012Let $(M,g)$ be a spacetime which admits a complete timelike conformal Killing vector field $K$. We prove that $(M,g)$ splits globally as a standard conformastationary spacetime with respect to $K$ if and only if $(M,g)$ is distinguishing (and, thus causally ... More
On the definition and examples of Finsler metricsNov 22 2011Oct 01 2012For a standard Finsler metric F on a manifold M, its domain is the whole tangent bundle TM and its fundamental tensor g is positive-definite. However, in many cases (for example, the well-known Kropina and Matsumoto metrics), these two conditions are ... More
On the Eclipse of Thales, Cycles and ProbabilitiesJul 08 2013According to classical tradition, Thales of Miletus predicted the total solar eclipse that took place on 28 May 585 BCE. Even if some authors have flatly denied the possibility of such a prediction, others have struggled to find cycles which would justify ... More
Quantum and Classical Fields in the Finite-Dimensional FormalismOct 09 2001The quantization rules recently proposed by M. Navarro (and independently I.V. Kanatchikov) for a finite-dimensional formulation of quantum field theory are applied to the Klein-Gordon and the Dirac fields to obtain the quantum equations of motion of ... More
Symmetries in two-dimensional dilaton gravity with matterJun 13 1997Sep 10 1997The symmetries of generic 2D dilaton models of gravity with (and without) matter are studied in some detail. It is shown that $\delta_2$, one of the symmetries of the matterless models, can be generalized to the case where matter fields of any kind are ... More
A note on causally simple and globally hyperbolic spacetimesOct 27 2006Nov 28 2006This paper has been withdrawn because the part concerning the definition of global hyperbolicity has already been included in an expanded and clearer way in gr-qc/0611138. The remainder will be also extended and posted.
Norm-attaining compact operatorsJun 05 2013Jun 13 2014We show examples of compact linear operators between Banach spaces which cannot be approximated by norm attaining operators. This is the negative answer to an open question posed in the 1970's. Actually, any strictly convex Banach space failing the approximation ... More
Modeling the multiwavelength emission from G73.9+0.9: Gamma-rays from a SNR-MC interactionSep 12 2015G73.9+0.9 has been classified as a probable shell-type supernova remnant (SNR), although it has also been suggested that this object could be a pulsar wind nebula (PWN). Here, a broadband model of the non-thermal emission of G73.9+0.9 from radio to gamma-rays ... More
Spherical CR Dehn SurgerySep 15 2015Consider a three dimensional cusped spherical $\mathrm{CR}$ manifold $M$ and suppose that the holonomy representation of $\pi_1(M)$ can be deformed in such a way that the peripheral holonomy is generated by a non-parabolic element. We prove that, in this ... More
twister - a P2P microblogging platformDec 26 2013This paper proposes a new microblogging architecture based on peer-to-peer networks overlays. The proposed platform is comprised of three mostly independent overlay networks. The first provides distributed user registration and authentication and is based ... More
A-homology, A-homotopy and spectral sequencesApr 19 2011May 08 2014Given a CW-complex A we define an `A-shaped' homology theory which behaves nicely towards A-homotopy groups allowing the generalization of many classical results. We also develop a relative version of the Federer spectral sequence for computing A-homotopy ... More
Multiple-antenna fading coherent channels with arbitrary inputs: Characterization and optimization of the reliable information transmission rateOct 25 2012We investigate the constrained capacity of multiple-antenna fading coherent channels, where the receiver knows the channel state but the transmitter knows only the channel distribution, driven by arbitrary equiprobable discrete inputs in a regime of high ... More
Character varieties for real formsOct 17 2016Let $\Gamma$ be a finitely generated group and $G$ a real form of $\mathrm{SL}_n(\mathbb{C})$. We propose a definition for the $G$-character variety of $\Gamma$ as a subset of the $\mathrm{SL}_n(\mathbb{C})$-character variety of $\Gamma$. We consider ... More
Geodesic connectedness of semi-Riemannian manifoldsMay 04 2000Sep 12 2000The question whether a Riemannian manifold is geodesically connected can be studied from geometrical as well as variational methods, and accurate results can be obtained by using the associated distance and related properties of the positive-definiteness. ... More
Spherical CR uniformization of Dehn surgeries of the Whitehead link complementFeb 15 2018We apply a spherical CR Dehn surgery theorem in order to obtain infinitely many Dehn surgeries of the Whitehead link complement that carry spherical CR structures. We consider as starting point the spherical CR uniformization of the Whitehead link complement ... More
Toric Kahler Metrics: Cohomogeneity One Examples of Constant Scalar Curvature in Action-Angle CoordinatesDec 02 2009In these notes, after an introduction to toric Kahler geometry, we present Calabi's family of U(n)-invariant extremal Kahler metrics in symplectic action-angle coordinates and show that it actually contains, as particular cases, many interesting cohomogeneity ... More
Polymer representations and geometric quantizationNov 02 2011Polymer representations of the Weyl algebra of linear systems provide the simplest analogues of the representation used in loop quantum gravity. The construction of these representations is algebraic, based on the Gelfand-Naimark-Segal construction. Is ... More
Asymptotic Distribution Of The Roots Of The Ehrhart Polynomial Of The Cross-PolytopeDec 10 2010We use the method of steepest descents to study the root distribution of the Ehrhart polynomial of the $d$-dimensional cross-polytope, namely $\mathcal{L}_{d}$, as $d\rightarrow \infty$. We prove that the distribution function of the roots, approximately, ... More
Hardy-Littlewood inequalities for norms of positive operators on sequence spacesAug 15 2012We consider estimates of Hardy and Littlewood for norms of operators on sequence spaces, and we apply a factorization result of Maurey to obtain improved estimates and simplified proofs for the special case of a positive operator.
Why old tires are still being preferred as dock bumpers in harboursMay 28 2012Sep 26 2012The usage of old tires as dock and tugboat bumpers has been a common practice from long ago, proving to be safe for docking even the largest freighters. The reaction force and stored energy of an axially compressed tire is studied in order to determine ... More
Recent progress on the notion of global hyperbolicityDec 12 2007Feb 25 2010Global hyperbolicity is a central concept in Mathematical Relativity. Here, we review the different approaches to this concept explaining both, classical approaches and recent results. The former includes Cauchy hypersurfaces, naked singularities, and ... More
Null to time-like infinity Green's functions for asymptotic symmetries in Minkowski spacetimeSep 04 2015We elaborate on the Green's functions that appeared in [1,2] when generalizing, from massless to massive particles, various equivalences between soft theorems and Ward identities of large gauge symmetries. We analyze these Green's functions in considerable ... More
Universe made of baryonic gravitating particles behaves as a ΛCDM UniverseMay 02 2014Sep 10 2014Using an approximate solution to the $N$-body problem in general relativity, and the \emph{principle of local isotropy at any point}, we construct a cosmological model, with zero curvature, for a universe composed uniquely by collision-less gravitating ... More
The version for compact operators of Lindenstrauss properties A and BFeb 25 2015It has been very recently discovered that there are compact linear operators between Banach spaces which cannot be approximated by norm attaining operators. The aim of this expository paper is to give an overview of those examples and also of sufficient ... More
Invariant subspaces and Deddens algebrasMar 20 2014It is shown that if the Deddens algebra ${\mathcal D}_T$ associated with a quasinilpotent operator $T$ on a complex Banach space is closed and localizing then $T$ has a nontrivial closed hyperinvariant subspace.
Einstein-Cartan Theory and Gauge SymmetryDec 13 2012Mar 08 2013We argue that the non gauge invariant coupling between torsion and the Maxwell or Yang-Mills fields in Einstein-Cartan theory can not be ignored. Arguments based in the existence of normal frames in neighbourhoods, and an approximation to a \delta-function, ... More
Quantum Mechanics and Leggett's InequalitiesJun 27 2008Jul 08 2008We show that when the proper description of the behaviour of individual photons or spin 1/2 particles in a spherically symmetric entangled pair is done through the use of the density matrix, the Leggett's inequality is not violated by quantum mechanics. ... More
EPR, Bell, GHZ, and Hardy theorems, and quantum mechanicsAug 09 2005We review the theorems of Einstein-Podolsky-Rosen (EPR), Bell, Greenberger-Horne-Zeilinger (GHZ), and Hardy, and present arguments supporting the idea that quantum mechanics is a complete, causal, non local, and non separable theory.
The CPT Group of the Dirac FieldApr 16 2004Aug 12 2004Using the standard representation of the Dirac equation we show that, up to signs, there exist only TWO SETS of consistent solutions for the matrices of charge conjugation (C), parity (P), and time reversal (T). In both cases, P^2=-1, and then two succesive ... More
Some criteria for Wind Riemannian completeness and existence of Cauchy hypersurfacesMar 14 2017Jun 05 2017Recently, a link between Lorentzian and Finslerian Geometries has been carried out, leading to the notion of wind Riemannian structure (WRS), a generalization of Finslerian Randers metrics. Here, we further develop this notion and its applications to ... More
Wind Riemannian spaceforms and Randers metrics of constant flag curvatureJan 05 2017Recently, wind Riemannian structures (WRS) have been introduced as a generalization of Randers and Kropina metrics. They are constructed from the natural data for Zermelo navigation problem, namely, a Riemannian metric $g_R$ and a vector field $W$ (the ... More
The Hamiltonian Tube Of A Cotangent-Lifted ActionOct 14 2014The Marle-Guillemin-Sternberg (MGS) form is local model for a neighborhood of an orbit of a Hamiltonian Lie group action on a symplectic manifold. One of the main features of the MGS form is that it puts simultaneously in normal form the existing symplectic ... More
On contact invariants of non-simply connected Gorenstein toric contact manifoldsDec 26 2018The first two authors showed in~\cite{AM1} how the Conley-Zehnder index of any contractible periodic Reeb orbit of a non-degenerate toric contact form on a good toric contact manifold with zero first Chern class, i.e. a Gorenstein toric contact manifold, ... More
Evidence-Based Comparison of Modularity Support Between Java and Object TeamsSep 09 2011Background: Aspect-oriented programming (AOP) is an emerging programming paradigm whose focus is about improving modularity, with an emphasis on the modularization of crosscutting concerns. Objective: The goal of this paper is to assess the extent to ... More
On the interplay between Lorentzian Causality and Finsler metrics of Randers typeMar 20 2009Dec 04 2010We obtain some results in both Lorentz and Finsler geometries, by using a correspondence between the conformal structure (Causality) of standard stationary spacetimes on $M=\R\times S$ and Randers metrics on $S$. In particular, for stationary spacetimes, ... More
Quantum theory of a two-mode open-cavity laserMay 09 2011Aug 25 2011We develop the quantum theory of an open-cavity laser assuming that only two modes compete for gain. We show that the modes interact to build up a collective mode that becomes the lasing mode when pumping exceeds a threshold. This collective mode exhibits ... More
Discrete Rotational Symmetry, Moment Isotropy, and High Order Lattice Boltzmann ModelsSep 10 2007Conventional lattice Boltzmann models only satisfy moment isotropy up to fourth order. In order to accurately describe improtant physical effects beyond the isothermal Navier-Stokes fluid regime, higher order isotropy is required. In this paper, we present ... More
Nonlinear mushy-layer convection with chimneys: stability and optimal solute fluxesMay 04 2012Dec 21 2012We model buoyancy-driven convection with chimneys -- channels of zero solid fraction -- in a mushy layer formed during directional solidification of a binary alloy in two-dimensions. A large suite of numerical simulations is combined with scaling analysis ... More
On the Uniqueness of Kinematics of Loop Quantum CosmologySep 19 2012The holonomy-flux algebra $\A$ of loop quantum gravity is known to admit a natural representation that is uniquely singled out by the requirement of covariance under spatial diffeomorphisms. In the cosmological context, the requirement of spatial homogeneity ... More
Function classes and relational constraints stable under compositions with clonesFeb 07 2009The general Galois theory for functions and relational constraints over arbitrary sets described in the authors' previous paper is refined by imposing algebraic conditions on relations.
Second order hydrodynamics of a CFT plasma from boost invariant expansionAug 12 2008Sep 08 2008We compute finite coupling correction to a nonlinear second order hydrodynamic coefficient in the boost invariant expansion of the N=4 supersymmetric Yang-Mills plasma. The result is universal for a large class of strongly coupled four dimensional conformal ... More
3D Euler equations and ideal MHD mapped to regular systems: probing the finite-time blowup hypothesisJul 15 2010Dec 03 2010We prove by an explicit construction that solutions to incompressible 3D Euler equations defined in the periodic cube can be mapped bijectively to a new system of equations whose solutions are globally regular. We establish that the usual Beale-Kato-Majda ... More
Propagation of Chaos in a Coagulation ModelOct 13 2011A deterministic coalescing dynamics with constant rate for a particle system in a finite volume with a fixed initial number of particles is considered. It is shown that, in the thermodynamic limit, with the constraint of fixed density, the corresponding ... More
Bounded rational points on curvesAug 02 2013Sep 04 2013We establish the sharp estimate <<_d N^{2/d} for the number of rational points of height at most N on an irreducible projective curve of degree d. We deduce this from a result for general hypersurfaces that is sensitive to the coefficients of the corresponding ... More
Distribution of ranks of β-decay half-livesNov 21 2010I studied the distribution of ranks of values of 2949 {\beta}-decay half-lives according to an empirical beta law with two exponents. {\beta}-decay half-life ranks showed good fit to a beta function with two exponents.
Hitting and returning into rare events for all alpha-mixing processesMar 25 2010May 31 2010We prove that for any $\alpha$-mixing stationnary process the hitting time of any $n$-string $A_n$ converges, when suitably normalized, to an exponential law. We identify the normalization constant $\lambda(A_n)$. A similar statement holds also for the ... More