Results for "Gioia Rau"

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ALMA observations of the "fresh" carbon-rich AGB star TX Piscium. The discovery of an elliptical detached shellNov 19 2018Aims. The carbon-rich asymptotic giant branch (AGB) star TX Piscium (TX Psc) has been observed multiple times during multiple epochs and at different wavelengths and resolutions, showing a complex molecular CO line profile and a ring-like structure in ... More
A Cluster Deficit in the ROSAT NEP SurveyNov 29 1999We have used data from the deepest region of the ROSAT All-Sky Survey, the North Ecliptic Pole (NEP) region, to produce a complete and unbiased X-ray selected sample of distant clusters to understand the nature of cluster evolution and determine implications ... More
High Angular Resolution Astrophysics: Resolving Stellar Surface FeaturesMar 11 2019We are now in an era where we can image details on the surfaces of stars. When resolving stellar surfaces, we see that every surface is uniquely complicated. Each imaged star provides insight into not only the stellar surface structures, but also the ... More
GHRS Observations of Cool, Low-Gravity Stars. VI Mass-Loss Rates and Wind Parameters for M GiantsNov 26 2018The photon-scattering winds of M-giants absorb parts of the chromospheric emission lines and produce self-reversed spectral features in high resolution {\it HST}/GHRS spectra. These spectra provide an opportunity to assess fundamental parameters of the ... More
Turbulent Friction in Rough Pipes and the Energy Spectrum of the Phenomenological TheoryJul 08 2005Dec 20 2005The classical experiments on turbulent friction in rough pipes were performed by J. Nikuradse in the 1930's. Seventy years later, they continue to defy theory. Here we model Nikuradse's experiments using the phenomenological theory of Kolmog\'orov, a ... More
RXJ1716.6+6708: a protocluster at z=0.81?Oct 13 1999At z=0.809, RXJ1716.6+6708 is the second most distant X-ray selected cluster so far published and the only one with a large number of spectroscopically determined cluster member velocities. The optical morphology of RXJ1716.6+6708 resembles an inverted ... More
X-ray Selected Clusters of GalaxiesJan 21 1996This paper given at the meeting on "Mapping, Measuring and Modelling the Universe" presents three topics: 1) the study of the clusters and groups of galaxies found serendipitously in the North Ecliptic Pole (NEP) region of the ROSAT all-sky survey; 2) ... More
X-ray Clusters at High RedshiftNov 30 1997As the largest gravitationally bound structures known, clusters provide clear constraints on the formation of structure and on the composition of the universe. Despite their extreme importance for cosmology the number of clusters at high redshift (z > ... More
A new discriminant algebra constructionMar 18 2015Dec 10 2015A discriminant algebra operation sends a commutative ring $R$ and an $R$-algebra $A$ of rank $n$ to an $R$-algebra $\Delta_{A/R}$ of rank $2$ with the same discriminant bilinear form. Constructions of discriminant algebra operations have been put forward ... More
Cluster SurveysOct 03 2000I review some of the current efforts to create unbiased samples of galaxy clusters. Readers are referred elsewhere for general wide area sky surveys and redshift surveys, and for Sunyaev-Zeldovich, radio, infrared and submm surveys, some of which were ... More
$L^{\infty}$ estimates and integrability by compensation in Besov-Morrey spaces and applicationsJan 03 2010$L^{\infty}$ estimates in the integrability by compensation result of H. Wente fail in dimension larger than two when Sobolev spaces are replaced by the ad-hoc Morrey spaces. However, in this paper we prove that $L^{\infty}$ estimates hold in arbitrary ... More
On the metric structure of space-timeSep 28 2010I present an analysis of the physical assumptions needed to obtain the metric structure of space-time. For this purpose I combine the axiomatic approach pioneered by Robb with ideas drawn from works on Weyl's "Raumproblem". The concept of a Lorentzian ... More
Statistical Mechanics in a NutshellMay 18 1998I give a concise introduction to some essential concepts of statistical mechanics: 1. Probability theory (constrained distributions, concentration theorem, frequency estimation, hypothesis testing); 2. Macroscopic systems in equilibrium (macrostate, thermodynamic ... More
Transport theory yields renormalization group equationsDec 13 1996Feb 18 1997We show that dissipative transport and renormalization can be described in a single theoretical framework. The appropriate mathematical tool is the Nakajima-Zwanzig projection technique. We illustrate our result in the case of interacting quantum gases, ... More
Pair Production in the Quantum Boltzmann EquationFeb 09 1994A source term in the quantum Boltzmann equation, which accounts for the spontaneous creation of $e^+e^-$-pairs in external electric fields, is derived from first principles and evaluated numerically. Careful analysis of time scales reveals that this source ... More
Moments and Classification for Conjugation-Invariant Rotations and Fake Uniformity in the Stochastic Radon TransformMar 06 2012We consider a generalisation of the stochastic Radon transform, introduced for an inverse problem in tomography by Panaretos. Specifically, we allow the distribution of the three-dimensional rotation in the statistical model of that work to be different ... More
Fake uniformity in a shape inversion formulaMar 06 2012Dec 29 2017We revisit a shape inversion formula derived by Panaretos in the context of a particle density estimation problem with unknown rotation of the particle. A distribution is presented which imitates, or 'fakes', the uniformity or Haar distribution that is ... More
Intersections on tropical moduli spacesDec 19 2008Aug 24 2015This article explores to which extent the algebro-geometric theory of rational descendant Gromov-Witten invariants can be carried over to the tropical world. Despite the fact that the tropical moduli-spaces we work with are non-compact, the answer is ... More
Two-phase densification of cohesive granular aggregatesMay 02 2001When poured into a container, cohesive granular materials form low-density, open granular aggregates. If pressed upon with a ram, these aggregates densify by particle rearrangement. Here we introduce experimental evidence to the effect that particle rearrangement ... More
Reconstructing the relaxation dynamics induced by an unknown heat bathMar 14 2011Dec 08 2011In quantum state tomography, one potential source of error is uncontrolled contact of the system with a heat bath whose detailed properties are not known, and whose impact on the system moreover varies between different runs of the experiment. Precisely ... More
Inferring the Gibbs state of a small quantum systemAug 21 2010Mar 03 2011Gibbs states are familiar from statistical mechanics, yet their use is not limited to that domain. For instance, they also feature in the maximum entropy reconstruction of quantum states from incomplete measurement data. Outside the macroscopic realm, ... More
On quantum vs. classical probabilityOct 10 2007Apr 28 2009Quantum theory shares with classical probability theory many important properties. I show that this common core regards at least the following six areas, and I provide details on each of these: the logic of propositions, symmetry, probabilities, composition ... More
Ballistic Transport Through Chaotic Cavities: Can Parametric Correlations and the Weak Localization Peak be Described by a Brownian Motion Model?Aug 24 1994A Brownian motion model is devised on the manifold of S-matrices, and applied to the calculation of conductance-conductance correlations and of the weak localization peak. The model predicts that (i) the correlation function in $B$ has the same shape ... More
Convergence of macrostates under reproducible processesApr 26 2010May 03 2010I show that whenever a system undergoes a reproducible macroscopic process the mutual distinguishability of macrostates, as measured by their relative entropy, diminishes. This extends the second law which regards only ordinary entropies, and hence only ... More
Measurement-based quantum foundationsSep 05 2009Jan 31 2010I show that quantum theory is the only probabilistic framework that permits arbitrary processes to be emulated by sequences of local measurements. This supports the view that, contrary to conventional wisdom, measurement should not be regarded as a complex ... More
Sur le nombre de points visités par une marche aléatoire sur un amas infini de percolationMay 02 2006In this article, we consider random walk on the infinite cluster of bond percolation on $\Z^d (d \geq 2)$. We show that the Laplace transformation of the number of visited points $N\_n$, has a behaviour as the random walk was on $\Z^d$. More precisely, ... More
Radio interferometric imaging of spatial structure that varies with time and frequencyAug 20 2012The spatial-frequency coverage of a radio interferometer is increased by combining samples acquired at different times and observing frequencies. However, astrophysical sources often contain complicated spatial structure that varies within the time-range ... More
Entropy Production via Particle ProductionOct 24 1994I critically examine the notion of ``irreversibility,'' and discuss in what sense it applies to the spontaneous creation of particles in external fields. The investigation reveals that particle creation in very strong fields can only be described by a ... More
Appearance of Gibbs states in quantum-state tomographyApr 08 2014Dec 19 2014I investigate the extent to which the description of quantum systems by Gibbs states can be justified purely on the basis of tomographic data, without recourse to theoretical concepts such as infinite ensembles, environments, information, or to the systems' ... More
Assessing thermalization and estimating the Hamiltonian with output data onlySep 12 2011I consider the generic situation where a finite number of identical test systems in varying (possibly unknown) initial states are subjected independently to the same unknown process. I show how one can infer from the output data alone whether or not the ... More
Existence of graphs with sub exponential transitions probability decay and applicationsApr 18 2007In this paper, we present a complete proof of the construction of graphs with bounded valency such that the simple random walk has a return probability at time $n$ at the origin of order $exp(-n^{\alpha}),$ for fixed $\alpha \in [0,1[$ and with Folner ... More
Lower bounds and asymptotics of real double Hurwitz numbersMay 23 2018We study the real counterpart of double Hurwitz numbers, called real double Hurwitz numbers here. We establish a lower bound for these numbers with respect to their dependence on the distribution of branch points. We use it to prove, under certain conditions, ... More
Reconstruction of Markovian dynamics from untimed dataMar 22 2015I develop a theoretical framework for inferring nonequilibrium equations of motion from incomplete experimental data. I focus on genuinely irreversible, Markovian processes, for which the incomplete data are given in the form of snapshots of the macrostate ... More
Evidence procedure for efficient quantum state tomographyApr 05 2010Jun 27 2010I show that in tomographic experiments measurement of a small set of observables suffices to confirm or incrementally amend prior expectations with a high degree of confidence. To this end I adapt the evidence procedure, an estimation technique used in ... More
Geometric magnetism in classical transport theoryMar 14 1997May 28 1997The effective dynamics of a slow classical system coupled to a fast chaotic environment is described by means of a Master equation. We show how this approach permits a very simple derivation of geometric magnetism.
Algebraic approach to renormalizationJul 27 1996In close analogy to the Bloch-Feshbach formalism known from the theory of nuclear dynamics, I develop a mathematical framework that allows one to understand renormalization in terms of purely algebraic operations (projections, dilatations) in Hilbert ... More
Reasoning about quantum systems at the macroscopic levelMay 25 2008In this didactical note I review in depth the rationale for using generalised canonical distributions in quantum statistics. Particular attention is paid to the proper definitions of quantum entropy and quantum relative entropy, as well as to quantum ... More
Consistent reasoning about a continuum of hypotheses on the basis of finite evidenceJun 15 2007In the modern Bayesian view classical probability theory is simply an extension of conventional logic, i.e., a quantitative tool that allows for consistent reasoning in the presence of uncertainty. Classical theory presupposes, however, that--at least ... More
Dynamics and habitability in circumstellar planetary systems of known binary starsMay 22 2016Dec 02 2016We present a survey on exoplanetary systems of binary stars with stellar separations less than 100 au. For a sample of 11 binaries that harbour detected circumstellar giant planets we investigate the frequency of systems with secular resonances (SR) affecting ... More
Rough-conduit flows and the existence of fully developed turbulenceAug 14 2005It is widely believed that at high Reynolds number (Re) all turbulent flows approach a state of "fully developed turbulence" defined by a unique, Re-independent statistics of the velocity fluctuations. Yet direct measurements of the velocity fluctuations ... More
Constraints on CDM theories from observations of massive, X-ray luminous clusters of galaxies at high redshiftFeb 26 1995During the course of a gravitational lensing survey of distant, X-ray selected, EMSS clusters of galaxies, we have studied 6 X-ray luminous (Lx > 5x10^44 h_{50}^{-2} erg s^{-1}) clusters at redshifts exceeding z=0.5. All of these clusters are apparently ... More
The EMSS catalog of X-ray-selected clusters of galaxies. I. An atlas of CCD images of 41 distant clustersMay 31 1994An atlas of deep, wide-field R-band CCD images of a complete sample of distant, X-ray-selected clusters of galaxies is presented. These clusters are the 41 most distant (z>= 0.15) and most X-ray luminous (Lx >= 2x10**44 erg\s-1) clusters in the Einstein ... More
Extreme fluctuations and the finite lifetime of the turbulent stateJun 19 2009Mar 10 2010We argue that the transition to turbulence is controlled by large amplitude events that follow extreme distribution theory. The theory suggests an explanation for recent observations of the turbulent state lifetime which exhibit super-exponential scaling ... More
On the Weak Lefschetz Property for Vector Bundles on $\mathbb P^2$Mar 27 2018Let $R=\mathbb K[x,y,z]$ be a standard graded polynomial ring where $\mathbb K$ is an algebraically closed field of characteristic zero. Let $M = \oplus_j M_j$ be a finite length graded $R$-module. We say that $M$ has the Weak Lefschetz Property if there ... More
Quantitative Boltzmann Gibbs principles via orthogonal polynomial dualityDec 22 2017We study fluctuation fields of orthogonal polynomials in the context of particle systems with duality. We thereby obtain a systematic orthogonal decomposition of the fluctuation fields of local functions, where the order of every term can be quantified. ... More
Constraining Stellar Photospheres as an Essential Step for Transmission Spectroscopy of Small ExoplanetsMar 14 2019Transmission spectra probe the atmospheres of transiting exoplanets, but these observations are also subject to signals introduced by magnetic active regions on host stars. Here we outline scientific opportunities in the next decade for providing useful ... More
The Advanced Spectral Library (ASTRAL): Reference Spectra for Evolved M-StarsNov 28 2018The HST Treasury Program "Advanced Spectral Library Project: Cool Stars" was designed to collect representative, high quality ultraviolet spectra of eight evolved F-M type cool stars. The Space Telescope Imaging Spectrograph (STIS) echelle spectra of ... More
Cool, evolved stars: results, challenges, and promises for the next decadeMar 11 2019Cool, evolved stars are the main source of chemical enrichment of the interstellar medium (ISM), and understanding their mass loss and structure offers a unique opportunity to study the cycle of matter in the Universe. Pulsation, convection, and other ... More
Homeomorphisms of One-dimensional Inverse Limits with Applications to Substitution Tilings, Unstable Manifolds, and Tent MapsMay 31 1999Suppose that f and g are Markov surjections, each defined on a wedge of circles, each fixing the branch point and having the branch point as the only critical value. We show that if the points in the inverse limit spaces associated with f and g corresponding ... More
Existence of the harmonic measure for random walks on graphs and in random environmentsNov 22 2011Feb 15 2012We give a sufficient condition for the existence of the harmonic measure from infinity of transient random walks on weighted graphs. In particular, this condition is verified by the random conductance model on $\Z^d$, $d\geq 3$, when the conductances ... More
Improved approximation for two dimensional strip packing with polynomial bounded widthOct 14 2016We study the well-known two-dimensional strip packing problem. Given is a set of rectangular axis-parallel items and a strip of width $W$ with infinite height. The objective is to find a packing of these items into the strip, which minimizes the packing ... More
Renormalization by Projection: On the Equivalence of the Bloch-Feshbach Formalism and Wilson's RenormalizationNov 15 1995Jul 02 1996We employ projection operator techniques in Hilbert space to derive a continuous sequence of effective Hamiltonians which describe the dynamics on successively larger length scales. We show for the case of \phi^4 theory that the masses and couplings in ... More
Exit time for anchored expansionMar 23 2009Jul 02 2015Let $(X_n)_{n\geq 0}$ be a reversible random walk on a graph $G$ satisfying an anchored isoperimetric inequality. We give upper bounds for exit time (and occupation time in transient case) by X of any set which contains the root. As an application, we ... More
Probabilistic Mortality Forecasting with Varying Age-Specific Survival ImprovementsNov 21 2013Jan 13 2014We propose a probabilistic mortality forecasting model that can be applied to derive forecasts for populations with regular and irregular mortality developments. Our model (1) uses rates of mortality improvement to model dynamic age patterns of mortality ... More
Tropical Real Hurwitz numbersDec 13 2014Aug 25 2015In this paper, we define tropical analogues of real Hurwitz numbers, i.e. numbers of covers of surfaces with compatible involutions satisfying prescribed ramification properties. We prove a correspondence theorem stating the equality of the tropical numbers ... More
First Steps in Tropical Intersection TheorySep 24 2007Jan 20 2009We establish first parts of a tropical intersection theory. Namely, we define cycles, Cartier divisors and intersection products between these two (without passing to rational equivalence) and discuss push-forward and pull-back. We do this first for fans ... More
Three bodies bind even when two do not: Efimov states and Fano resonances in atoms and nucleiJun 08 2007Efimov's prediction more than three decades ago that three-body bound states can exist when the pairwise attractions do not bind or only support weakly bound states of a pair, has remained unconfirmed till just the past year. This lecture provides the ... More
Two-qubit analogs of octonions and projective planesAug 05 2008Apr 01 2009A quantum spin-1/2, and its associated su(2) algebra of Pauli spin matrices are familiarly linked to Clifford algebra and quaternions. Somewhat more loosely, we develop connections between the su(4) algebra of two spins and of its sub-algebras, which ... More
Quantum InterpretationsJun 03 2006Difficulties and discomfort with the interpretation of quantum mechanics are due to differences in language between it and classical physics. Analogies to The Special Theory of Relativity, which also required changes in the basic worldview and language ... More
Broadband X-ray Spectroscopy of GRS 1915+105Nov 09 2000We analyzed RXTE data of GRS 1915+105 of X-ray low states between 1996 and 1998. The X-ray spectrum is dominated by the power law component. We found (i) that the power law is pivoting at 10-30 keV, (ii) that the power law slope correlates with radio ... More
Generalized Bloch equations for a strongly driven tunneling systemMay 15 1996Nov 07 1996Using the Robertson projection operator formalism, we derive generalized Bloch equations which describe the dynamics of a biased two-level tunneling system strongly driven by an external field and weakly coupled to a super-Ohmic heat bath. The generalized ... More
Comptonization and reflection of X-ray radiation and the X-ray-radio correlation in the chi-states of GRS 1915+105Jul 22 2002Oct 06 2002We present a comprehensive X-ray study of four years of pointed RXTE observations of GRS 1915+105 in the chi-state. We interpret the behavior of the hard power law tail spectrum as coming from inverse Compton scattering of soft disk photons on a thermally ... More
The X-ray spectrum of LSI+61o303May 17 2001It had been proposed earlier that the hard X-ray and gamma-ray radiation of the Be/X-ray system LSI+61o303 could be due to inverse Compton scattering of optical photons from the Be star by the same electron population which also produces the radio emission. ... More
Gamma-Ray Bursts: The multiwavelength context in 2015 and beyondFeb 21 2011We collect information as complete as possible about the upcoming telescopes and facilities relevant to gamma-ray bursts, both in the electromagnetic bands as well as for non-electromagnetic messengers. We describe the expected synergy between these new ... More
Supersymmetry in quantum mechanics: An extended viewJan 23 2004The concept of supersymmetry in a quantum mechanical system is extended, permitting the recognition of many more supersymmetric systems, including very familiar ones such as the free particle. Its spectrum is shown to be supersymmetric, with space-time ... More
Microscopic theory of absorption and emission in nanostructured solar cells: Beyond the generalized Planck formulaDec 08 2009Absorption and emission in inorganic bipolar solar cells based on low dimensional structures exhibiting the effects of quantum confinement is investigated in the framework of a comprehensive microscopic theory of the optical and electronic degrees of ... More
Q-curve and area rules for choosing heuristic parameter in Tikhonov regularizationSep 06 2018We consider choice of the regularization parameter in Tikhonov method if the noise level of the data is unknown. One of the best rules for the heuristic parameter choice is the quasi-optimality criterion where the parameter is chosen as the global minimizer ... More
Heuristic parameter choice in Tikhonov method from minimizers of the quasi-optimality functionAug 07 2017We consider choice of the regularization parameter in Tikhonov method in the case of the unknown noise level of the data. From known heuristic parameter choice rules often the best results were obtained in the quasi-optimality criterion where the parameter ... More
Comptonization, the X-ray-radio correlation and the long-term periodicity in the chi-states of GRS 1915+105Jul 23 2002We analyzed 139 chi-state observations of GRS 1915+105 with RXTE from 1997 to 2000 and found i) that the observations fall into two groups with different Comptonization behavior, ii) that the slope of the hard X-ray component correlates with the radio ... More
What is Physics: The individual and the universal, and seeing past the noiseMay 09 2016Along with weaving together observations, experiments, and theoretical constructs into a coherent mesh of understanding of the world around us, physics over its past five centuries has continuously refined the base concepts on which the whole framework ... More
Dimensions, nodes and phases in quantum numbersJun 26 2009Students of quantum mechanics encounter discrete quantum numbers in a somewhat incoherent and bewildering number of ways. For each physical system studied, quantum numbers seem to be introduced in its own specific way, some enumerating from 1 and others ... More
Linear Time Algorithms for Multiple Cluster Scheduling and Multiple Strip PackingFeb 09 2019We study the Multiple Cluster Scheduling problem and the Multiple Strip Packing problem. For both problems, there is no algorithm with approximation ratio better than $2$ unless $P = NP$. In this paper, we present an algorithm with approximation ratio ... More
Tropical rational equivalence on R^rNov 18 2008Aug 08 2014We introduce an improved version of rational equivalence in tropical intersection theory which can be seen as a replacement of chapter 8 of our previous article arXiv:0709.3705v2. Using this new definition, rational equivalence is compatible with push-forwards ... More
R.A.Fisher, design theory, and the Indian connectionOct 21 2009Design Theory, a branch of mathematics, was born out of the experimental statistics research of the population geneticist R. A. Fisher and of Indian mathematical statisticians in the 1930s. The field combines elements of combinatorics, finite projective ... More
Algebraic characterization of X-states in quantum informationJun 25 2009A class of two-qubit states called X-states are increasingly being used to discuss entanglement and other quantum correlations in the field of quantum information. Maximally entangled Bell states and "Werner" states are subsets of them. Apart from being ... More
From Reversible Quantum Microdynamics to Irreversible Quantum TransportMay 08 1995The transition from reversible microdynamics to irreversible transport can be studied very efficiently with the help of the so-called projection method. We give a concise introduction to that method, illustrate its power by using it to analyze the well-known ... More
The diagonal of tropical matroid varieties and cycle intersectionsDec 15 2010We define an intersection product of tropical cycles on matroid varieties (via cutting out the diagonal) and show that it is well-behaved. In particular, this enables us to intersect cycles on moduli spaces of tropical rational marked curves $M_{0,n}$ ... More
A Microscopic Perspective on Photovoltaic Reciprocity in Ultrathin Solar CellsFeb 08 2017Apr 14 2017The photovoltaic reciprocity theory relates the electroluminescence spectrum of a solar cell under applied bias to the external photovoltaic quantum efficiency of the device as measured at short circuit conditions. Its derivation is based on detailed ... More
Tropical descendant Gromov-Witten invariantsSep 08 2008Nov 29 2009We define tropical Psi-classes on the moduli space of rational tropical curves in R^2 and consider intersection products of Psi-classes and pull-backs of evaluations on this space. We show a certain WDVV equation which is sufficient to prove that tropical ... More
Weak Lensing Observations of High-Redshift Clusters of GalaxiesNov 10 1999We present results of a weak gravitational lensing survey of six X-ray selected high-redshift clusters of galaxies. We find that the masses of the clusters derived from weak lensing are comparable to those derived from the X-ray observations. We show ... More
Global solutions of a free boundary problem via mass transport inequalitiesFeb 22 2014Jun 10 2014We study a free boundary problem which arises as the continuum version of a stochastic particles system in the context of Fourier law. Local existence and uniqueness of the classical solution are well known in the literature of free boundary problems. ... More
Folding Energetics in Thin-Film DiaphragmsMay 02 2000We perform experiments on thin-film diaphragms to show that the folding patterns of anisotropically compressed diaphragms are strikingly different from those of isotropically compressed ones. We then use a simple von Karman model to relate the overall ... More
A Statistical Comparative Planetology Approach to Maximize the Scientific Return of Future Exoplanet Characterization EffortsMar 12 2019Provided that sufficient resources are deployed, we can look forward to an extraordinary future in which we will characterize potentially habitable planets. Until now, we have had to base interpretations of observations on habitability hypotheses that ... More
Weak Lensing by High-Redshift Clusters of Galaxies - I: Cluster Mass ReconstructionJan 20 2000We present the results of a weak lensing survey of six high-redshift (z > 0.5), X-ray selected clusters of galaxies. We have obtained ultra-deep R-band images of each cluster with the Keck Telescope, and have measured a weak lensing signal from each cluster. ... More
Evolution of X-ray Luminous Clusters from z=0.3 to z=0.8Jul 24 2001Observations of the highest redshift clusters provide the longest lever arm in the attempt to evaluate the evolution of their bulk properties. I present the most recent results on galaxy cluster evolution based on data from the ROSAT North Ecliptic Pole ... More
Towards Correctness of Program Transformations Through Unification and Critical Pair ComputationDec 22 2010Correctness of program transformations in extended lambda calculi with a contextual semantics is usually based on reasoning about the operational semantics which is a rewrite semantics. A successful approach to proving correctness is the combination of ... More
Signed counts of real simple rational functionsDec 15 2017We study the problem of counting real simple rational functions $\varphi$ with prescribed ramification data (i.e. a particular class of oriented real Hurwitz numbers of genus $0$). We introduce a signed count of such functions that is invariant under ... More
Duality for stochastic models of transportDec 13 2012Jun 11 2013We study three classes of continuous time Markov processes (inclusion process, exclusion process, independent walkers) and a family of interacting diffusions (Brownian energy process). For each model we define a boundary driven process which is obtained ... More
Dualities in population genetics: a fresh look with new dualitiesFeb 13 2013Oct 19 2014We apply our general method of duality, introduced in [Giardina', Kurchan, Redig, J. Math. Phys. 48, 033301 (2007)], to models of population dynamics. The classical dualities between forward and ancestral processes can be viewed as a change of representation ... More
Asymmetric stochastic transport models with ${\mathcal{U}}_q(\mathfrak{su}(1,1))$ symmetryJul 06 2015By using the algebraic construction outlined in \cite{CGRS}, we introduce several Markov processes related to the ${\mathcal{U}}_q(\mathfrak{su}(1,1))$ quantum Lie algebra. These processes serve as asymmetric transport models and their algebraic structure ... More
A generalized Asymmetric Exclusion Process with $U_q(\mathfrak{sl}_2)$ stochastic dualityJul 12 2014We study a new process, which we call ASEP$(q,j)$, where particles move asymmetrically on a one-dimensional integer lattice with a bias determined by $q\in (0,1)$ and where at most $2j\in\mathbb{N}$ particles per site are allowed. The process is constructed ... More
Local density of diffeomorphisms with large centralizersSep 27 2007Given any compact manifold M, we construct a non-empty open subset O of the space of C^1-diffeomorphisms of M and a dense subset D of O such that the centralizer of every diffeomorphism in D is uncountable, hence non-trivial.
A multi-scale multi-frequency deconvolution algorithm for synthesis imaging in radio interferometryJun 14 2011Aims : We describe MS-MFS, a multi-scale multi-frequency deconvolution algorithm for wide-band synthesis-imaging, and present imaging results that illustrate the capabilities of the algorithm and the conditions under which it is feasible and gives accurate ... More
Self-consistent redshift estimation using correlation functions without a spectroscopic reference sampleFeb 07 2018We present a new method to estimate redshift distributions and galaxy-dark matter bias model parameters (gdmbm) using correlation functions in a fully data driven manner. Unlike other machine learning, template methods, or correlation redshift methods, ... More
On the axioms of Leibniz algebroids associated to Nambu-Poisson manifoldsOct 22 2015Let $E \rightarrow M$ be a smooth vector bundle with a bilinear product on $\Gamma(E)$ satisfying the Jacobi identity. Assuming only the existence of an anchor map $\mathfrak{a}$ we show that $\mathfrak{a}([X,Y]) = [\mathfrak{a}X,\mathfrak{a}Y]_c$. This ... More
Marangoni shocks in unobstructed soap-film flowsJan 22 2009Sep 15 2009It is widely thought that in steady, gravity-driven, unobstructed soap-film flows, the velocity increases monotonically downstream. Here we show experimentally that the velocity increases, peaks, drops abruptly, then lessens gradually downstream. We argue ... More
The Galois closure for rings and some related constructionsFeb 04 2015Let $R$ be a ring and let $A$ be a finite projective $R$-algebra of rank $n$. Manjul Bhargava and Matthew Satriano have recently constructed an $R$-algebra $G(A/R)$, the Galois closure of $A/R$. Many natural questions were asked at the end of their paper. ... More
The nature of the DLS fast transientsApr 16 2006Apr 27 2006The discovery and study of highly transient sources, especially those which rise to high brightness and then fade to obscurity, has been a major part of modern astrophysics. Well known examples include supernovae and novae. A byproduct of the Deep Lens ... More
Accounting for Secondary Uncertainty: Efficient Computation of Portfolio Risk Measures on Multi and Many Core ArchitecturesOct 08 2013Aggregate Risk Analysis is a computationally intensive and a data intensive problem, thereby making the application of high-performance computing techniques interesting. In this paper, the design and implementation of a parallel Aggregate Risk Analysis ... More
Bracket-Preserving property of Anchor Maps and Applications to Various BracketsJul 04 2016Let $E \rightarrow M$ be a smooth vector bundle with a bilinear product on $\Gamma(E)$ satisfying the Jacobi identity. Assuming only the existence of an anchor map $\mathfrak{a}$ we show that $\mathfrak{a}([X,Y]) = [\mathfrak{a}X,\mathfrak{a}Y]_c$. This ... More