Results for "Andrzej Udalski"

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A New Non-Planetary Interpretation of the Microlensing Event OGLE-2013-BLG-0723Apr 22 2016Recently, the discovery of a Venus-mass planet orbiting a brown-dwarf host in a binary system was reported from the analysis of the microlensing event OGLE-2013-BLG-0723. We reanalyze the event considering the possibility of other interpretations. From ... More
OGLE-2011-BLG-0417: A Radial Velocity Testbed for MicrolensingFeb 04 2013Microlensing experiments are returning increasingly detailed information about the planetary and binary systems that are being detected, far beyond what was originally expected. In several cases the lens mass and distance are measured, and a few very ... More
The Intrinsic I-Band Magnitude Dispersion of the Galactic Bulge Red ClumpMay 31 2011Jul 04 2011We measure the intrinsic magnitude dispersion of the Galactic bulge red clump (RC) using two different methods and arrive at an estimate of \sigma_{I} ~ 0.17 mag. We first estimate the width of the RC by analyzing in detail a sample of RC measurements ... More
An algorithm to detect blends with eclipsing binaries in planet transit searchesJan 17 2005We present an algorithm that can detect blends of bright stars with fainter, un-associated eclipsing binaries. Such systems contaminate searches for transiting planets, in particular in crowded fields where blends are common. Spectroscopic follow-up observations ... More
A remarkable sample of new symbiotic stars towards the Galactic BulgeMay 21 2013Symbiotic stars are the longest orbital period interacting binaries, where nova-like outbursts are generated by the accretion of a high mass loss rate red giant wind onto a white dwarf companion. Long-term photometric monitoring surveys such as OGLE and ... More
OGLE-SMC-LPV-00861 (LIN 9): the first proven Z And outburst in a Magellanic symbiotic starJun 18 2014We report on the discovery of a new Small Magellanic Cloud (SMC) symbiotic star, OGLE-SMC-LPV-00861, previously catalogued as H$\alpha$ emission line source LIN 9. The OGLE light curve shows multiple-maxima outburst behaviour over $\sim$1200 d with a ... More
The Magellanic Quasars Survey. I. Doubling the Number of Known AGNs Behind the Small Magellanic CloudFeb 03 2011We report the spectroscopic confirmation of 29 new, 12 plausible, and 3 previously known quasars behind the central ~1.5 deg^2 region of the Small Magellanic Cloud. These were identified in a single 2df/AAOmega observation on the Anglo-Australian Telescope ... More
Symbiotic stars and other Halpha emission line stars towards the Galactic BulgeMay 21 2013Symbiotic stars are interacting binaries with the longest orbital periods and their multi-component structure makes them rich astrophysical laboratories. The accretion of a high mass loss rate red giant wind on to a white dwarf (WD) makes them promising ... More
The Optical Gravitational Lensing Experiment. Real Time Data Analysis Systems in the OGLE-III SurveyJan 08 2004We describe three real time data analysis systems implemented during the third phase of the OGLE survey (OGLE-III). The EWS system is designed to detect on-going microlensing events. The EEWS system monitors the microlensing phenomena for anomalies from ... More
The Optical Gravitational Lensing Experiment. Red Clump Stars as a Distance IndicatorOct 08 1999Jan 14 2000We present relation of the mean I-band brightness of red clump stars on metallicity. Red clump stars were proposed to be a very attractive standard candle for distance determination. The calibration is based on 284 nearby red giant stars whose high quality ... More
XROM and RCOM: Two New OGLE-III Real Time Data Analysis SystemsOct 13 2008We describe two new OGLE-III real time data analysis systems: XROM and RCOM. The XROM system has been designed to provide continuous real time photometric monitoring of the optical counterparts of X-ray sources while RCOM system provides real time photometry ... More
The Optical Gravitational Lensing Experiment. Is Interstellar Extinction Toward the Galactic Center Anomalous?Oct 16 2002Mar 03 2003Photometry of the Galactic bulge, collected during the OGLE-II microlensing search, indicates high and non-uniform interstellar extinction toward the observed fields. We use the mean I-band magnitude and V-I color of red clump stars as a tracer of interstellar ... More
Optical Gravitational Lensing Experiment. Population Effects on the Mean Brightness of the Red Clump StarsJul 09 1998Sep 02 1998We present an empirical test indicating that the mean I-band magnitude of the red clump stars, used as the standard candle in the recent distance determinations to the Magellanic Clouds and other objects, is age independent for intermediate age (2-10 ... More
Spectral and temporal properties of RX J0520.5-6932 (LXP 8.04) during a type-I outburstMay 28 2014We observed RX J0520.5-6932 in the X-rays and studied the optical light curve of its counterpart to verify it as a Be/X-ray binary. We performed an XMM-Newton anticipated target of opportunity observation in January 2013 during an X-ray outburst of the ... More
Frequency of Hot Jupiters and Very Hot Jupiters from the OGLE-III Transit Surveys Toward the Galactic Bulge and CarinaJan 02 2006We derive the frequencies of hot Jupiters (HJs) with 3--5 day periods and very hot Jupiters (VHJs) with 1-3 day periods by comparing the planets actually detected in the OGLE-III survey with those predicted by our models. The models are constructed following ... More
Is Quasar Optical Variability a Damped Random Walk?Feb 16 2012Feb 22 2013The damped random walk (DRW) model is increasingly used to model the variability in quasar optical light curves, but it is still uncertain whether the DRW model provides an adequate description of quasar optical variability across all time scales. Using ... More
A D'-type symbiotic binary in the planetary nebula SMP LMC 88Feb 08 2018SMP LMC 88 is one of the planetary nebulae (PN) in the Large Magellanic Cloud. We identify in its spectrum Raman scattered O VI lines at 6825 and 7083A. This unambiguously classifies the central object of the nebula as a symbiotic star (SySt). We identified ... More
Robust Filtering of Artifacts in Difference Imaging for Rapid Transients DetectionJan 23 2016Real-time analysis and classification of observational data collected within synoptic sky surveys is a huge challenge due to constant growth of data volumes. Machine learning techniques are often applied in order to perform this task automatically. The ... More
Triple Microlens OGLE-2008-BLG-092L: Binary Stellar System with a Circumprimary Uranus-type PlanetAug 26 2014Jun 25 2015We present the gravitational microlensing discovery of a 4 M_Uranus planet that orbits a 0.7 M_Sun star at ~18 AU. This is the first known analog of Uranus. Similar planets, i.e., cold ice-giants, are inaccessible to either radial velocity or transit ... More
Correction to Low and Lapsley's article "Optimization Flow Control, I: Basic Algorithm and Convergence"Sep 21 2002Oct 08 2016In the note an error in Low and Lapsley's article ("Optimization Flow Control, I: Basic Algorithm and Convergence", IEEE/ACM Transactions on Networking, 7(6), pp. 861-874, 1999) is pointed out. Because of this error the proof of the Theorem 2 presented ... More
On the Lojasiewicz exponent of the gradient of a polynomial functionMar 19 1997Let h = \sum h_{\alpha \beta} X^\alpha Y^\beta be a polynomial with complex coefficients. The Lojasiewicz exponent of the gradient of h at infinity is the upper bound of the set of all real \lambda such that |grad h(x, y)| >= c|(x,y)|^\lambda in a neighbourhood ... More
Phenomenology of pp->pp eta reaction close to thresholdSep 22 2003The recent high statistics measurement of the pp -> pp eta reaction at an excess energy Q=15.5 MeV has been analysed by means of partial wave decomposition of the cross section. Guided by the dominance of the final state 1S0 pp interaction (FSI), we keep ... More
Packing large trees of consecutive ordersOct 26 2015Nov 10 2015A conjecture by Bollob\'as from 1995 (which is a weakenning of the famous Tree Packing Conjecture by Gy\'arf\'as from 1976) states that any set of $k$ trees $T_n,T_{n-1},\dots,T_{n-k+1}$, such that $T_{n-i}$ has $n-i$ vertices, pack into $K_n$, provided ... More
HPV and cervical cancer in Moldova, epidemiological model with intervention cost vs benefit and effectiveness analysisApr 21 2015Human papillomavirus, or HPV, is a sexually transmittable virus infection, which is necessary risk factor for developing cervical cancer, first most common type of cancer in working age women in Moldova. We observe both behavioral change (sexuality increase) ... More
Finite size of hadrons and Bose-Einstein CorrelationsApr 06 2015In this presentation I report on the results of the paper we published recently together with Kacper Zalewski. It exploits the consequences of the observation that the hadrons, being the composite objects, cannot be produced too close to each other and ... More
Gamma ray bursts may be blueshifted bundles of the relic radiationFeb 02 2015Sep 22 2015A hypothesis is proposed that the gamma-ray bursts (GRBs) may arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The blueshift mechanism is provided by such a Lema\^itre -- Tolman (L--T) model, ... More
Tensor Networks for Big Data Analytics and Large-Scale Optimization ProblemsJul 11 2014Aug 22 2014In this paper we review basic and emerging models and associated algorithms for large-scale tensor networks, especially Tensor Train (TT) decompositions using novel mathematical and graphical representations. We discus the concept of tensorization (i.e., ... More
Four-dimensional Causal Dynamical Triangulations and an effective transfer matrixFeb 12 2013Causal Dynamical Triangulations is a background independent approach to quantum gravity. We show that there exists an effective transfer matrix labeled by the scale factor which properly describes the evolution of the quantum universe. In this framework ... More
On the structure of fixed-point sets of asymptotically regular semigroupsJan 04 2012We extend a few recent results of G\'{o}rnicki (2011) asserting that the set of fixed points of an asymptotically regular mapping is a retract of its domain. In particular, we prove that in some cases the resulting retraction is H\"{o}lder continuous. ... More
Life time of correlation between stocks prices on established and emerging marketsMay 31 2011The correlation coefficient between stocks depends on price history and includes information on hierarchical structure in financial markets. It is useful for portfolio selection and estimation of risk. I introduce the Life Time of Correlation between ... More
On open-open games of uncountable lengthAug 06 2012The aim of this note is to investigate the open-open game of uncountable length. We introduce a cardinal number $\mu(X)$, which says how long the Player I has to play to ensure a victory. It is proved that $\su(X)\leq\mu(X)\leq\su(X)^+$. We also introduce ... More
Universally Kuratowski-Ulam space and open-open gamesFeb 09 2012Feb 10 2012We examine the class of spaces in which the second player has winning strategy in the open-open game. We shown that this space is not an universally Kuratowski-Ulam. We also show that the games G and G7 introduced by Daniels, Kunen, Zhou "On the open-open ... More
Causal Dynamical Triangulations in Four DimensionsNov 29 2011Recent results obtained within a non-perturbative approach to quantum gravity based on the method of four-dimensional Causal Dynamical Triangulations are described. The phase diagram of the model consists of three phases. In the physically most interesting ... More
Hierarchical structure in phonographic marketMay 31 2011I find a topological arrangement of assets traded in a phonographic market which has associated a meaningful economic taxonomy. I continue using the Minimal Spanning Tree and the Life-time Of Correlations between assets, but now outside the stock markets. ... More
Maxwell's Equations for MagnetsMar 03 2011Oct 27 2014Magnetostatic fields in accelerators are conventionally described in terms of multipoles. We show that in two dimensions, multipole fields do provide solutions of Maxwell's equations, and we consider the distributions of electric currents and geometries ... More
On the commutativity of states in von Neumann algebrasSep 28 2014The notion of commutativity of two normal states on a von Neumann algebra was defined some time ago by means of the Pedersen-Takesaki theorem. In this note we aim at generalizing this notion to an arbitrary number of states, and obtaining some results ... More
Wave propagation in anisotropic viscoelasticityMay 22 2014Jul 01 2015We extend the theory of complete Bernstein functions to matrix-valued functions and apply it to analyze Green's function of an anisotropic multi-dimension\-al linear viscoelastic problem. Green's function is given by the superposition of plane waves. ... More
A Class of Linear Positive Maps in Matrix AlgebrasJul 18 2003A class of linear positive, trace preserving maps in $M_n$ is given in terms of affine maps in $\bBR^{n^2-1}$ which map the closed unit ball into itself.
Comment on "AdS nonlinear instability: moving beyond spherical symmetry" [Class. Quantum Grav. 33 23LT01 (2016)]Nov 30 2016We argue that if the degeneracy of the spectrum of linear perturbations of AdS is properly taken into account, there are globally regular, time-periodic, asymptotically AdS solutions (geons) bifurcating from each linear eigenfrequency of AdS.
Boundary Harnack Principle for fractional powers of Laplacian on the Sierpinski carpetMar 16 2005We prove the Boundary Harnack Principle related to fractional powers of Laplacian for some natural regions in the two-dimensional Sierpinski carpet. This is a natual application of a probabilistic method based on the Ikeda-Watanabe formula
Centering problems for probability measures on finite dimensional vector spacesJan 12 2010The paper deals with various centering problems for probability measures on finite dimensional vector spaces. We show that for every such measure there exists a vector $h$ satisfying $\mu*\delta(h)=S(\mu*\delta (h))$ for each symmetry $S$ of $\mu$, generalizing ... More
On the tensor product construction for q-differential algebrasMay 23 1997We show that for $q\not=-1$ the q-graded tensor product fails to preserve the q-differential structure of the product algebra and therefore there is no natural tensor product construction for q-differential algebras.
Some remarks on relativistic zero-mass wave equations and supersymmetryApr 07 2013Apr 14 2013We study several formulations of zero-mass relativistic equations, stressing similarities between different frameworks. It is shown that all these massless wave equations have fermionic as well as bosonic solutions.
Eta invariants for flat manifoldsJan 08 2010May 02 2011Using H. Donnelly result from the article "Eta Invariants for G-Spaces" we calculate the eta invariants of the signature operator for almost all 7-dimensional flat manifolds with cyclic holonomy group. In all cases this eta invariants are an integer numbers. ... More
Alexander-Spanier cohomology and boundary of a domainJul 08 2012Jul 22 2015We investigate a property: a domain cuts the ambient space if and only if it's boundary is disconnected. Previously, we had shown that for compact manifolds this property is equivalent to the manifold having trivial 1-cohomology. We now generalize this ... More
The eigenvectors of semigroups of positive maps on von Neumann algebrasNov 23 2009The eigenvectors of an ergodic semigroup of linear normal positive unital maps on a von Neumann algebra are described. Moreover, it is shown by means of examples, that mere positivity of the maps in question is not sufficient for Frobenius theory as in ... More
On the material geometry of continuously defective corrugated graphene sheetsJul 05 2014Dec 22 2014Geometrical objects describing the material geometry of continuously defective graphene sheets are introduced and their compatibility conditions are formulated. Effective edge dislocations embedded in the Riemann-Cartan material space and defined by their ... More
From Duffin-Kemmer-Petiau to Tzou algebras in relativistic wave equationsJan 08 2018We study relation between the Duffin-Kemmer-Petiau algebras and some representations of Tzou algebras. Working in the setting of relativistic wave equations we reduce, via a similarity transformation, five and ten dimensional Duffin-Kemmer-Petiau algebras ... More
A Myers-type theorem and compact Ricci solitonsMar 02 2004Let the Ricci curvature of a compact Riemannian manifold be greater, at every point, than the Lie derivative of the metric with respect to some fixed smooth vector field. It is shown that the fundamental group then has only finitely many conjugacy classes. ... More
Wodzicki residue and minimal operators on a noncommutative 4-dimensional torusJun 16 2013We compute the Wodzicki residue of the inverse of a conformally rescaled Laplace operator over a 4-dimensional noncommutative torus. We show that the straightforward generalization of the Laplace-Beltrami operator to the noncommutative case is not the ... More
Dynamical Noncommutative SpheresDec 19 2001We introduce a family of noncommutative 4-spheres, such that the instanton projector has its first Chern class trivial: $ch_1(e) = B \chi + b \xi$. We construct for them a 4-dimensional cycle and calculate explicitly the Chern-Connes paring for the instanton ... More
Towards a self-consistent model of analogue gravitySep 13 2005A nonlinear scalar field theory from which an effective metric can be deduced is considered. This metric is shown to be compatible with requirements of general relativity. It is demonstrated that there is a class of solutions which fulfill both the nonlinear ... More
Differential cross sections for muonic atom scattering from hydrogenic moleculesAug 24 2006The differential cross sections for low-energy muonic hydrogen atom scattering from hydrogenic molecules are directly expressed by the corresponding amplitudes for muonic atom scattering from hydrogen-isotope nuclei. The energy and angular dependence ... More
Pure homology of algebraic varietiesFeb 27 2003Sep 07 2003We show that for a complete complex algebraic variety the pure component of homology coincides with the image of intersection homology. Therefore pure homology is topologically invariant. To obtain slightly more general results we introduce "image homology" ... More
Residue forms on singular hypersurfacesJan 27 2003Apr 05 2005The purpose of this paper is to point out a relation between the canonical sheaf and the intersection complex of a singular algebraic variety. We focus on the hypersurface case. Let $M$ be a complex manifold, $X\subset M$ a singular hypersurface. We study ... More
Formality of equivariant intersection cohomologyJan 23 2001Dec 18 2001We present several approaches to equivariant intersection cohomology. We show that for a complete algebraic variety acted by a connected algebraic group $G$ it is a free module over $H^*(BG)$. The result follows from the decomposition theorem or from ... More
Twists and spectral triples for isospectral deformationsFeb 09 2001Mar 02 2001We construct explicitly the symmetries of the isospectral deformations as twists of Lie algebras and demonstrate that they are isometries of the deformed spectral triples.
On lower semicontinuous multifunctions in quasi-uniform and vector spacesApr 10 2002Given a cover $\mathcal{B}$ of a quasi-uniform space $Y$ we introduce a concept of lower semicontinuity for multifunctions $F:X\to 2^Y$, called $\mathcal{B}$-lsc. In this way, we get a common description of Vietoris-lsc, Hausdorff-lsc, and bounded-Hausdorff-lsc ... More
Explicit example of collapsing kappa^+ in iteration of kappa-proper forcingsAug 05 2018We give an example of iteration of length omega of (<kappa)-complete kappa^+-cc forcing notions with the limit collapsing kappa^+. The construction is decoded from the proof of Shelah [Proper and Improper Forcing, Appendix, Theorem 3.6(1)].
SU(1,1) group action and the corresponding Bloch equationOct 31 2009Discrete time dynamics on the SU(1,1) group is studied. It is shown that a map acting in the dual space is the stroboscopic map for a SU(1,1) Bloch equation. Exact solution of the map is used to elucidate the corresponding dynamics. It is shown that dynamics ... More
On wave propagation in viscoelastic media with concave creep complianceFeb 07 2013Mar 28 2013It is proved that the attenuation function of a viscoelastic medium with a non-decreasing and concave creep compliance is sublinear in the high frequency range.
A simple proof of a duality theorem with applications in viscoelasticityApr 09 2018A new concise proof is given of a duality theorem connecting completely monotone relaxation functions with Bernstein class creep functions. The proof makes use of the theory of complete Bernstein functions and Stieltjes functions and is based on a relation ... More
Complexity Threshold for Functioning Directed Networks in Damage Size DistributionApr 21 2010A certain complexity threshold is proposed which defines the term `complex network' for RSN, e.g. Kauffman networks with s>=2 - more than two equally probable state variants. Such Kauffman networks are no longer Boolean networks. RSN are different than ... More
Variables suitable for constructing quantum states for the Teleparallel Equivalent of General Relativity IMay 20 2013Mar 03 2014We present the first part of an analysis aimed at introducing variables which are suitable for constructing a space of quantum states for the Teleparallel Equivalent of General Relativity via projective techniques - the space is meant to be applied in ... More
Kinematic quantum states for the Teleparallel Equivalent of General RelativityApr 24 2013Jul 14 2014A space of kinematic quantum states for the Teleparallel Equivalent of General Relativity is constructed by means of projective techniques. The states are kinematic in this sense that their construction bases merely on the structure of the phase space ... More
ADM-like Hamiltonian formulation of gravity in the teleparallel geometryNov 23 2011Sep 19 2013We present a new Hamiltonian formulation of the Teleparallel Equivalent of General Relativity (TEGR) meant to serve as the departure point for canonical quantization of the theory. TEGR is considered here as a theory of a cotetrad field on a spacetime. ... More
Asymptotic structure of electrodynamics revisitedApr 14 2016Feb 14 2017We point out that recently published analyses of null and timelike infinity and long-range structures in electrodynamics to large extent rediscover results present in literature. At the same time, some of the conclusions these recent works put forward ... More
Twisted Dirac Operators over Quantum SpheresApr 20 2007We construct new families of spectral triples over quantum spheres, with a particular attention focused on the standard Podles quantum sphere and twisted Dirac operators.
Quasi-Dirac Operators and Quasi-FermionsFeb 12 2006Aug 29 2008We investigate examples of quasi-spectral triples over two-dimensional commutative sphere, which are obtained by modifying the order-one condition. We find equivariant quasi-Dirac operators and prove that they are in a topologically distinct sector than ... More
Structure of the time projection for stopping times in von Neumann algebrasNov 15 2002We give an explicit formula for the time projection in an arbitrary von Neumann algebra from which all its basic properties can be easily derived. The analysis of the situation when this time projection is a conditional expectation is also performed.
The super fixed point property for asymptotically nonexpansive mappingsMar 29 2012We show that the super fixed point property for nonexpansive mappings and for asymptotically nonexpansive mappings in the intermediate sense are equivalent. As a consequence, we obtain fixed point theorems for asymptotically nonexpansive mappings in uniformly ... More
Splitting the Kemmer-Duffin-Petiau EquationsSep 04 2003We study internal structure of the Kemmer-Duffin-Petiau equations for spin-0 and spin-1 mesons. We demonstrate, that the Kemmer-Duffin-Petiau equations can be splitted into constituent equations, describing particles with definite mass and broken Lorentz ... More
Semidirect product of CCR and CAR algebras and asymptotic states in quantum electrodynamicsNov 10 1997Jul 31 1998A C*-algebra containing the CCR and CAR algebras as its subalgebras and naturally described as the semidirect product of these algebras is discussed. A particular example of this structure is considered as a model for the algebra of asymptotic fields ... More
Differential cross sections for muonic atom scattering in solid hydrogenic targetsDec 30 2007The differential cross sections for low-energy muonic hydrogen atom scattering in solid molecular H$_2$, D$_2$ and T$_2$ targets under low pressure have been calculated for various temperatures. The polycrystalline fcc and hcp structure of the solid hydrogenic ... More
Residue in intersection homology for quasihomogeneous singularitiesNov 26 1996Suppose M is a complex manifold of dimension $n+1$ and K is a hypersurface in M. By Poincar\'e duality we define a residue morphism $res:H^{k+1}(M\setminus K)\longrightarrow H_{2n-k}(K)$ which generalizes the classical Leray residue morphism to cohomology ... More
Residues in intersection homology and L_p-cohomologyAug 10 1996Dec 02 1996Suppose $M^{n+1}$ is a complex manifold and K is a hypersurface with isolated singularities. Let $\omega$ be a holomorphic form on $M\setminus K$ with the first order pole on K. The Leray residue of such form gives an element in the n-th homology of K ... More
Purity at the endSep 10 2008Sep 06 2009We consider smooth completion of algebraic manifolds. Having some information about its singular completions or about completions of its images we prove purity of cohohomology of the set at infinity. We deduce also some topological properties. The work ... More
Theory of electromagnetic fieldsNov 18 2011Oct 27 2014We discuss the theory of electromagnetic fields, with an emphasis on aspects relevant to radiofrequency systems in particle accelerators. We begin by reviewing Maxwell's equations and their physical significance. We show that in free space, there are ... More
Repeatable light paths in the shearfree normal cosmological modelsMay 06 2011Aug 22 2011Conditions for the existence of repeatable light paths (RLPs) in the shearfree normal cosmological models are investigated. It is found that in the conformally nonflat models the only RLPs are radial null geodesics (in the spherical case) and their analogues ... More
How to generate and measure anomalous weakly non-ergodic Brownian motion in simple systemsMay 30 2012It is shown that in systems with time-dependent and/or spatially nonuniform temperature $T(t,x)$, (i) most of the transport processes is weakly non-ergodic, and (ii) the diffusion (Brownian motion, BM) is anomalous. A few examples of simple arrangements, ... More
Externally-driven transformations of vortex textures in flat submicrometer magnetsMay 20 2012Two effects of oscillatory transformations of vortex textures in flat nanomagnets due to the application of an external field or a spin-polarized electric current are analytically described with relevance to soft-magnetic structures of submicrometer sizes ... More
Domain-wall complexes in ferromagnetic stripesJan 27 2012Sep 04 2012Interaction of domain walls (DWs) in ferromagnetic stripes is studied with relevance to the formation of stable complexes of many domains. Two DW system is described with the Landau-Lifshitz-Gilbert equation including regimes of narrow and wide stripes ... More
The Sommerfeld enhancement for scalar particles and application to sfermion co-annihilation regionsFeb 21 2011Apr 13 2011We study the impact of the Sommerfeld enhancement on the thermal relic density of the lightest neutralino in the case of large co-annihilation effects with a scalar particle. The proper way of including the Sommerfeld effect in this case is discussed, ... More
Python for education: the exact cover problemOct 28 2010Python implementation of Algorithm X by Knuth is presented. Algorithm X finds all solutions to the exact cover problem. The exemplary results for pentominoes, Latin squares and Sudoku are given.
Era of Big Data Processing: A New Approach via Tensor Networks and Tensor DecompositionsMar 09 2014Aug 24 2014Many problems in computational neuroscience, neuroinformatics, pattern/image recognition, signal processing and machine learning generate massive amounts of multidimensional data with multiple aspects and high dimensionality. Tensors (i.e., multi-way ... More
Low-emittance storage ringsJul 08 2015The effects of synchrotron radiation on particle motion in storage rings are discussed. In the absence of radiation, particle motion is symplectic, and the beam emittances are conserved. The inclusion of radiation effects in a classical approximation ... More
Blueshifts in the Lemaître -- Tolman modelsSep 18 2014Nov 21 2014In the Lema\^{\i}tre -- Tolman (L--T) models that have nonconstant bang-time function $t_B(r)$, light emitted close to those points of the Big Bang where $\dril {t_B} r \neq 0$ is blueshifted at the receiver position. The blueshifted rays are expected ... More
Projective quantum states for Loop Quantum Gravity coupled to tensor fieldsJan 21 2016We present a construction of kinematic quantum states for theories of tensor fields of an arbitrary sort. The construction is based on projective techniques by Kijowski. Applying projective quantum states for Loop Quantum Gravity obtained by Lanery and ... More
Quantization of diffeomorphism invariant theories of connections with a non-compact structure group - an exampleMay 29 2006Mar 30 2013A simple diffeomorphism invariant theory of connections with the non-compact structure group R of real numbers is quantized. The theory is defined on a four-dimensional 'space-time' by an action resembling closely the self-dual Plebanski action for general ... More
Hilbert space built over connections with a non-compact structure groupJun 08 2004Mar 17 2005Quantization of general relativity in terms of SL(2,C)-connections (i.e. in terms of the complex Ashtekar variables) is technically difficult because of the non-compactness of SL(2,C). The difficulties concern the construction of a diffeomorphism invariant ... More
Elimination of memory from the equations of motion of hereditary viscoelasticity for increased efficiency of numerical integrationJun 29 2014Jul 06 2014A method of eliminating the memory from the equations of motion of linear viscoelasticity is presented. Replacing the unbounded memory by a quadrature over a finite or semi-finite interval leads to considerable reduction of computational effort and storage. ... More
Asymptotic estimates of viscoelastic Green's functions near the wavefrontJan 06 2014Jul 17 2015Asymptotic behavior of viscoelastic Green's functions near the wavefront is expressed in terms of a causal function $g(t)$ defined in \cite{SerHanJMP} in connection with the Kramers-Kronig dispersion relations. Viscoelastic Green's functions exhibit a ... More
Dispersion and attenuation for an acoustic wave equation consistent with viscoelasticityJul 28 2013Jan 30 2014An acoustic wave equation for pressure accounting for viscoelastic attenuation is derived from viscoelastic equations of motion. It differs significantly from the equations proposed by Szabo. Dispersion and attenuation associated with the viscoelastic ... More
Electroweak corrections to decays involving a charged Higgs bosonJun 20 1993Jun 24 1993We present complete one-loop radiative corrections to the decay rate of a top quark into a charged Higgs boson and a bottom quark, and for the decay of a charged Higgs boson into leptons. The results are discussed in the framework of the two Higgs boson ... More
Amdahl's and Gustafson-Barsis laws revisitedSep 06 2008The paper presents a simple derivation of the Gustafson-Barsis law from the Amdahl's law. In the computer literature these two laws describing the speedup limits of parallel applications are derived separately. It is shown, that treating the time of the ... More
Errors in Low and Lapsley's article "Optimization Flow Control, I: Basic Algorithm and Convergence"Sep 21 2002Oct 08 2016In the note two errors in Low and Lapsley's article "Optimization Flow Control, I: Basic Algorithm and Convergence", "IEEE/ACM Transactions on Networking", 7(6), pp. 861-874, 1999, are shown. Because of these errors the proofs of both theorems presented ... More
On matrix type corings, algebra coverings and Cech cohomologyApr 20 2007Mar 14 2008We investigate the a matrix-type coring associated to a complete covering of an algebra, its Amitsur complex and propose a definition for the related Cech cohomology relative to the covering.
Supersymmetric content of the Dirac and Duffin-Kemmer-Petiau equationsJun 07 2010We study subsolutions of the Dirac and Duffin-Kemmer-Petiau equations described in our earlier papers. It is shown that subsolutions of the Duffin-Kemmer-Petiau equations and those of the Dirac equation obey the same Dirac equation with some built-in ... More
n-localization propertyJul 25 2005Let n be an integer greater than 1. A tree T is an n-ary tree provided that every node in T has at most n immediate successors. A forcing notion P has the n-localization property if every function from omega to omega in an extension via P is an omega-branch ... More
Cosmological perturbations in the Regge-Wheeler formalismFeb 13 2019We study linear perturbations of the Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological model in the Regge-Wheeler formalism which is a standard framework to study perturbations of spherically-symmetric black holes. In particular, we show that the ... More