Results for "I. Beaton"

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The Domination Equivalence Classes of PathsOct 11 2017A dominating set $S$ of a graph $G$ of order $n$ is a subset of the vertices of $G$ such that every vertex is either in $S$ or adjacent to a vertex of $S$. %The domination number $G$, denoted $\gamma (G)$, is the cardinality of the smallest dominating ... More
Optimal Domination PolynomialsApr 12 2019Let $G$ be a graph on $n$ vertices and $m$ edges and $D(G,x)$ the domination polynomial of $G$. In this paper we completely characterize the values of $n$ and $m$ for which optimal graphs exist for domination polynomials. We also show that there does ... More
Independence Equivalence Classes of Paths and CyclesOct 12 2018The independence polynomial of a graph is the generating polynomial for the number of independent sets of each size. Two graphs are said to be \textit{independence equivalent} if they have equivalent independence polynomials. We extend previous work by ... More
A solvable non-directed model of polymer adsorptionJun 22 2015Prudent walks are self-avoiding walks which cannot step towards an already occupied vertex. We introduce a new model of adsorbing prudent walks on the square lattice, which start on an impenetrable surface and accrue a fugacity $a$ with each step along ... More
Partition function zeros of adsorbing Dyck pathsNov 02 2017Jan 25 2018The zeros of the size-$n$ partition functions for a statistical mechanical model can be used to help understand the critical behaviour of the model as $n\to\infty$. Here we use weighted Dyck paths as a simple model of two-dimensional polymer adsorption, ... More
Slicings of parallelogram polyominoes: Catalan, Schröder, Baxter, and other sequencesNov 16 2015Nov 21 2016We provide a new succession rule (i.e. generating tree) associated with Schr\"oder numbers, that interpolates between the known succession rules for Catalan and Baxter numbers. We define Schr\"oder and Baxter generalizations of parallelogram polyominoes, ... More
On consecutive pattern-avoiding permutations of length 4, 5 and beyondApr 28 2017Feb 20 2018We review and extend what is known about the generating functions for consecutive pattern-avoiding permutations of length 4, 5 and beyond, and their asymptotic behaviour. There are respectively, seven length-4 and twenty-five length-5 consecutive-Wilf ... More
The Enumeration of Prudent Polygons by Area and its Unusual AsymptoticsNov 29 2010Prudent walks are special self-avoiding walks that never take a step towards an already occupied site, and \emph{$k$-sided prudent walks} (with $k=1,2,3,4$) are, in essence, only allowed to grow along $k$ directions. Prudent polygons are prudent walks ... More
The critical pulling force for self-avoiding walksJul 08 2014Mar 16 2015Self-avoiding walks are a simple and well-known model of long, flexible polymers in a good solvent. Polymers being pulled away from a surface by an external agent can be modelled with self-avoiding walks in a half-space, with a Boltzmann weight $y = e^f$ ... More
The Carnegie-Chicago Hubble Program: Discovery of the Most Distant Ultra-faint Dwarf Galaxy in the Local UniverseJan 12 2017Ultra-faint dwarf galaxies (UFDs) are the faintest known galaxies and due to their incredibly low surface brightness, it is difficult to find them beyond the Local Group. We report a serendipitous discovery of an UFD, Fornax UFD1, in the outskirts of ... More
The critical surface fugacity of self-avoiding walks on a rotated honeycomb latticeOct 01 2012Oct 01 2013In a recent paper by Beaton et al, it was proved that a model of self-avoiding walks on the honeycomb lattice, interacting with an impenetrable surface, undergoes an adsorption phase transition when the surface fugacity is $1+\sqrt{2}$. Their proof used ... More
Adsorption of self-avoiding walks at a defectAug 28 2014Sep 01 2014We consider the model of self-avoiding walks on the $d$-dimensional hypercubic lattice interacting with a $d^*$-dimensional defect, where $1\leq d^*<d$. Such an interaction can be attractive or repulsive, and is controlled by a Boltzmann weight $a$ associated ... More
Unravelling the mystery of the M31 barMay 03 2006May 17 2006The inclination of M31 is too close to edge-on for a bar component to be easily recognised and is not sufficiently edge-on for a boxy/peanut bulge to protrude clearly out of the equatorial plane. Nevertheless, a sufficient number of clues allow us to ... More
The Near-Infrared Tip of the Red Giant Branch. II. An Absolute Calibration in the Large Magellanic CloudMar 04 2018We present a new empirical \(JHK\) absolute calibration of the tip of the red giant branch (TRGB) in the Large Magellanic Cloud (LMC). We use published data from the extensive \emph{Near-Infrared Synoptic Survey} containing 3.5 million stars, of which ... More
The Importance of Telescope Training in Data InterpretationJul 12 2019In this State of the Profession Consideration, we will discuss the state of hands-on observing within the profession, including: information about professional observing trends; student telescope training, beginning at the undergraduate and graduate levels, ... More
A numerical adaptation of SAW identities from the honeycomb to other 2D latticesOct 06 2011Oct 19 2011Recently, Duminil-Copin and Smirnov proved a long-standing conjecture by Nienhuis that the connective constant of self-avoiding walks on the honeycomb lattice is $\sqrt{2+\sqrt{2}}.$ A key identity used in that proof depends on the existence of a parafermionic ... More
The Near-Infrared Tip of the Red Giant Branch. I. A Calibration in the Isolated Dwarf Galaxy IC 1613Mar 04 2018Based on observations from the \emph{FourStar} near-infrared camera on the 6.5m Baade-Magellan telescope at Las Campanas, Chile, we present calibrations of the $JHK$ luminosities of stars defining the tip of the red giant branch (TRGB) in the halo of ... More
Using Surface Brightness Fluctuations to Study Nearby Satellite Galaxy Systems: the Complete Satellite System of M101Jan 22 2019We use surface brightness fluctuation (SBF) measurements to constrain the distance to low surface brightness (LSB) dwarfs in the vicinity of M101. Recent work has discovered many LSB candidate satellite companions of M101. However, without accurate distances, ... More
Knotting statistics for polygons in lattice tubesNov 30 2018We study several related models of self-avoiding polygons in a tubular subgraph of the simple cubic lattice, with a particular interest in the asymptotics of the knotting statistics. Polygons in a tube can be characterised by a finite transfer matrix, ... More
Polygons in restricted geometries subjected to infinite forcesApr 25 2016We consider self-avoiding polygons in a restricted geometry, namely an infinite $L\times M$ tube in $\mathbb Z^3$. These polygons are subjected to a force $f$, parallel to the infinite axis of the tube. When $f>0$ the force stretches the polygons, while ... More
Astronomical Distance Determination in the Space Age. Secondary distance indicatorsJan 02 2018The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating ... More
Comparison of Hipparcos Trigonometric and Mount Wilson Spectroscopic Parallaxes for 90 Subgiants that Defined the Class in 1935Nov 18 2015A history is given of the discovery between 1914 and 1935 of stars of intermediate luminosity between giants and dwarfs with spectral types between G0 to K3. The Mt Wilson spectroscopists identified about 90 such stars in their 1935 summary paper of spectroscopic ... More
Exact solution of some quarter plane walks with interacting boundariesJul 23 2018The set of random walks with different step sets (of short steps) in the quarter plane has provided a rich set of models that have profoundly different integrability properties. In particular, 23 of the 79 effectively different models can be shown to ... More
The Carnegie-Chicago Hubble Program: Calibration of the Near-Infrared RR Lyrae Period-Luminosity Relation With HSTDec 14 2018We present photometry of 30 Galactic RR Lyrae variables taken with HST WFC3/IR for the Carnegie-Chicago Hubble Program. These measurements form the base of the distance ladder measurements that comprise a pure Population II base to a measurement of Ho ... More
Two-dimensional self-avoiding walks and polymer adsorption: Critical fugacity estimatesOct 31 2011Recently Beaton, de Gier and Guttmann proved a conjecture of Batchelor and Yung that the critical fugacity of self-avoiding walks interacting with (alternate) sites on the surface of the honeycomb lattice is $1+\sqrt{2}$. A key identity used in that proof ... More
Using Surface Brightness Fluctuations to Study Nearby Satellite Galaxy Systems: Calibration and MethodologyJan 22 2019We explore the use of ground-based surface brightness fluctuation (SBF) measurements to constrain distances to nearby dwarf galaxies. Using archival CFHT Megacam imaging data for a sample of 27 nearby dwarfs, we demonstrate that reliable SBF measurements ... More
Quarter-plane lattice paths with interacting boundaries: the Kreweras and reverse Kreweras modelsMay 27 2019Lattice paths in the quarter plane have led to a large and varied set of results in recent years. One major project has been the classification of step sets according to the properties of the corresponding generating functions, and this has involved a ... More
2020 Vision: Towards a Sustainable OIR SystemJul 15 2019Open-access telescopes of all apertures are needed to operate a competitive and efficient national science program. While larger facilities contribute light-gathering power and angular resolution, smaller ones dominate for field of view, time-resolution, ... More
The First Ultra-Cool Brown Dwarf Discovered by the Wide-field Infrared Survey ExplorerNov 10 2010We report the discovery of the first new ultra-cool brown dwarf found with the Wide-field Infrared Survey Explorer (WISE). The object's preliminary designation is WISEPC J045853.90+643451.9. Follow-up spectroscopy with the LUCIFER instrument on the Large ... More
The Carnegie-Chicago Hubble Program. II. The Distance to IC 1613: The Tip of the Red Giant Branch and RR Lyrae Period-Luminosity RelationsMar 19 2017Oct 10 2017IC 1613 is an isolated dwarf galaxy within the Local Group. Low foreground and internal extinction, low metallicity, and low crowding make it an invaluable testbed for the calibration of the local distance ladder. We present new, high-fidelity distance ... More
The Carnegie-Chicago Hubble Program. III. The Distance to NGC 1365 via the Tip of the Red Giant BranchMar 30 2017Apr 04 2017The Carnegie-Chicago Hubble Program seeks to anchor the distance scale of Type Ia supernovae via the Tip of the Red Giant Branch (TRGB). Based on deep $Hubble$ $Space$ $Telescope$ ACS/WFC imaging, we present an analysis of the TRGB for the metal-poor ... More
The Carnegie-Chicago Hubble Program. V. The Distances to NGC 1448 and NGC 1316 via the Tip of the Red Giant BranchSep 05 2018Sep 13 2018The Carnegie-Chicago Hubble Program (CCHP) is re-calibrating the extragalactic SN Ia distance scale using exclusively Population II stars. This effort focuses on the Tip of the Red Giant Branch (TRGB) method, whose systematics are entirely independent ... More
Old-Aged Stellar Population Distance IndicatorsAug 28 2018Old-aged stellar distance indicators are present in all Galactic structures (halo, bulge, disk) and in galaxies of all Hubble types and, thus, are immensely powerful tools for understanding our Universe. Here we present a comprehensive review for three ... More
The Carnegie Chicago Hubble Program VI: Tip of the Red Giant Branch Distances to M66 and M96 of the Leo I GroupJul 12 2019We determine the distances to the Type Ia Supernova host galaxies M66 (NGC 3627) and M96 (NGC 3368) of the Leo I Group using the Tip of the Red Giant Branch (TRGB) method. We target the stellar halos of these galaxies using the Hubble Space Telescope ... More
The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant BranchJul 12 2019We present a new and independent determination of the local value of the Hubble constant based on a calibration of the Tip of the Red Giant Branch (TRGB) applied to Type Ia supernovae (SNeIa). We find a value of Ho = 69.8 +/- 0.8 (+/-1.1\% stat) +/- 1.7 ... More
The Proper Motion of Pyxis: the first use of Adaptive Optics in tandem with HST on a faint halo objectNov 25 2016Apr 01 2017We present a proper motion measurement for the halo globular cluster Pyxis, using HST/ACS data as the first epoch, and GeMS/GSAOI Adaptive Optics data as the second, separated by a baseline of about 5 years. This is both the first measurement of the proper ... More
Welcome to the Twilight Zone: The Mid-Infrared Properties of Poststarburst GalaxiesJul 31 2016We investigate the optical and Wide-field Survey Explorer (WISE) colors of "E+A" identified poststarburst galaxies, including a deep analysis on 190 poststarbursts detected in the 2MASS Extended Source Catalog. The poststarburst galaxies appear in both ... More
Welcome to the Twilight Zone: The Mid-Infrared Properties of Poststarburst GalaxiesJul 31 2016May 11 2017We investigate the optical and Wide-field Survey Explorer (WISE) colors of "E+A" identified post-starburst galaxies, including a deep analysis on 190 post-starbursts detected in the 2{\mu}m All Sky Survey Extended Source Catalog. The post-starburst galaxies ... More
TOI-150: A transiting hot Jupiter in the TESS southern CVZFeb 26 2019We report the detection of a hot Jupiter ($M_{p}=1.72\pm0.09\ M_{J}$, $R_{p}=1.38\pm0.04\ R_{J}$) orbiting a middle-aged star ($\log g=4.152^{+0.030}_{-0.043}$) in the TESS southern continuous viewing zone ($\beta=-79.59^{\circ}$). We confirm the planetary ... More
Exploring Halo Substructure with Giant Stars: The Nature of the Triangulum-Andromeda Stellar FeaturesJul 16 2014As large-scale stellar surveys have become available over the past decade, the ability to detect and characterize substructures in the Galaxy has increased dramatically. These surveys have revealed the Triangulum-Andromeda (TriAnd) region to be rich with ... More
Bridge between Hadrodynamics \& HEP: Regional CP Violation in Beauty \& Charm DecaysAug 23 2016There is a long way from `accuracy' to `precision' about {\bf CP} asymmetries in the decays of beauty \& charm hadrons. (a) We have to apply consistent parametrization of the CKM matrix. (b) Probing many-body final states (FS) is {\em not} a back-up for ... More
Memorial Contribution about Kolya Uraltsev's Talk at 2012 Workshop $B\to D**$Jul 02 2013Jul 14 2013Uraltev has given us a deeper understanding of the forces underlying the data from beauty and charm hadrons for the last 35 years and neutron EDM in the future -- in particular about non-perturbative QCD. At the Workshop in the November 2012 before his ... More
The Sybils' Advice on Charm (and $τ$ Leptons)Apr 05 2006The importance of future studies of charm and $\tau$ decays is emphasized as probes of New Physics: the most powerful tools are \cp asymmetries in charm and $\tau$ decays both in partial widths and final state distributions. While these searches for \cp ... More
The Battle of Albuera, the FC Liverpool and the Standard ModelMar 12 2006The Standard Model despite its well-known short comings is unlikely to yield without offering stubborn resistance. There are compelling arguments that New Physics lurks around the TeV scale. Continuing comprehensive studies of beauty, $\tau$ and charm ... More
Quo Vadis, Fascinum?Aug 14 1995The recent progress in our understanding of heavy-flavour decays allows us to define more reliably which future measurements on charm decays are needed to further advance our understanding of QCD and to get our theoretical tools ready for treating beauty ... More
Beauty Physics in the Next 15 Years -- an Itinerary for a Long Journey towards an Essential GoalJul 06 1994After re-stating why beauty physics is so special and sketching its present status I attempt to map out an itinerary for the next fifteen years. The basic elements are listed for a research program that allows to define and probe the KM unitarity triangle ... More
Weak Decays Of Charm Hadrons: The Next Lesson On QCD -- And Possibly More!Nov 01 1993Second-generation theoretical technologies -- heavy quark expansions, QCD sum rules and QCD simulations on the lattice -- are arriving on the scene, allowing a treatment of charm decays that is genuinely based on QCD. The availability of those theoretical ... More
On the Brink of Major Discoveries in Weak Charm Decays -- a Bismarckian Chance to Make HistoryOct 15 2007The recently obtained strong evidence for $D^0 - \bar D^0$ oscillations from the $B$ factories provides an important benchmark in our search for New Physics in charm transitions. While the theoretical verdict on the observed values of $x_D$ and $y_D$ ... More
The Physics of Beauty (& Charm [& $τ$]) at the LHC and in the Era of the LHCAug 20 2006The recent successes of the SM do not weaken the arguments in favour of New Physics residing at the TeV scale. Finding and identifying it represents the prime challenge for a generation of high energy physicists. To differentiate between different scenarios ... More
Measuring Absolute Branching Ratios of Charmed Baryons in $B$ DecaysNov 14 2001The $B$ factories are expected to provide huge samples of single $B$ decay events with little background by reconstructing one of the $B$ mesons produced in $\Upsilon (4S)$ decays. This represents a new experimental paradigm: such samples will allow to ... More
Heavy Flavour Physics: On Its More Than 50 Years Of History, Its Future And The Rio ManifestoDec 13 2000Dec 23 2000After a reminder about how $\Delta S\neq 0$ physics has been instrumental for the development of the Standard Model I sketch theoretical technologies for dealing with nonperturbative QCD in heavy flavour decays and state predictions for CP odd effects ... More
The Lifetimes of Heavy Flavour Hadrons - a Case Study in Quark-Hadron DualityJan 01 2000The status of heavy quark expansions for charm and beauty lifetime ratios is reviewed. Taking note of the surprising semiquantitative success of this description for charm hadrons I interprete the new data on $\tau (D_s)$ and re-iterate the call for more ... More
Memo on Extracting |V(cb)| and |V(ub)/V(cb)| from semileptonic B decaysJul 07 1999Heavy Quark Expansions for semileptonic decays of beauty hadrons are briefly reviewed. I analyze how $|V(cb)|$ can be extracted from the semileptonic width of $B$ mesons, the average semileptonic width of all weakly decaying beauty hadrons and from $B ... More
Inclusive $B_c$ Decays As A QCD LabOct 17 1995Phenomenological models of heavy flavour decays differ significantly in their predictions of global features of $B_c$ decays, like the $B_c$ lifetime or the relative weight of $c\ra s$ and $b\ra c$ transitions. The $1/m_Q$ expansion which is directly ... More
Lifetimes of Heavy-Flavour Hadrons -- Whence and Whither?Jul 21 1995Jul 27 1995A theoretical treatment for the weak decays of heavy-flavour hadrons has been developed that is genuinely based on QCD. Its methodology as it applies to total lifetimes and the underlying theoretical issues are sketched. Predictions are compared with ... More
Ultra High Energy Cosmic Rays and InflationJan 27 1999Two processes of matter creation after inflation: 1) gravitational creation of superheavy (quasi)stable particles, and 2) non-thermal phase transitions leading to formation of topological defects, may be relevant to the resolution of the puzzle of cosmic ... More
Bridge between Hadrodynamics & HEP: Regional CP Violation in Beauty & Charm DecaysAug 23 2016Oct 03 2016There is a long way from `accuracy' to `precision' about {\bf CP} asymmetries in the decays of beauty \& charm hadrons. (a) We have to apply consistent parametrization of the CKM matrix. (b) Probing many-body final states (FS) is {\em not} a back-up for ... More
Intercalant-Driven Superconductivity in YbC$_{6}$ and CaC$_{6}$Apr 06 2005Recently deiscovered superconductivity in YbC$_6$ and CaC$_6$ at temperatures substantially higher than previously known for intercalated graphites, raised several new questions: (1) Is the mechanism considerably different from the previously known intercalated ... More
Vitaly Ginzburg and High Temperature Superconductivity: Personal ReminiscencesAug 14 2007Aug 17 2007I offer some personal reminiscences from the period of 1976-1983, when I was a M. Sc. and then a Ph.D. student in Vitaly L. Ginzburg's High Temperature Superconductivity group at the P.N. Lebedev Institute in Moscow
Coding for Parallel Channels: Gallager Bounds for Binary Linear Codes with Applications to Repeat-Accumulate Codes and VariationsJul 02 2006This paper is focused on the performance analysis of binary linear block codes (or ensembles) whose transmission takes place over independent and memoryless parallel channels. New upper bounds on the maximum-likelihood (ML) decoding error probability ... More
Impact of Non-perturbative QCD on CP Violation in Many-Body Final States of Flavor TransitionsMay 26 2019Jun 06 2019The title of my talk pointed out central statements: the impact of non-perturbative QCD on {\bf CP} asymmetries in many-body FS in charm \& beauty hadrons. For practical reasons one measures first {\bf CP} violation in two-body final states of heavy flavor ... More
Electron bunch generation from a plasma photocathodeJul 01 2019Plasma waves generated in the wake of intense, relativistic laser or particle beams can accelerate electron bunches to giga-electronvolt (GeV) energies in centimetre-scale distances. This allows the realization of compact accelerators having emerging ... More
On a new method to estimate distance, reddening and metallicity of RR Lyrae stars using optical/near-infrared ($B$,$V$,$I$,$J$,$H$,$K$) mean magnitudes: $ω$ Centauri as a first test caseNov 17 2018We developed a new approach to provide accurate estimates of metal content, reddening and true distance modulus of RR Lyrae stars (RRLs). The method is based on homogeneous optical ($BVI$) and near-infrared ($JHK$) mean magnitudes and on predicted period--luminosity--metallicity ... More
CP Asymmetries (\& T Violation) in Known Matter -- and beyondNov 03 2014Aug 18 2016Finding \cp~violation (\CPV ) in 1964 produced a real revolution in the fundamental dynamics, although the community did not understand it right away. The paper by Kobayashi \& Maskawa \cite{KM} appeared in 1973 to describe \CPV~in classes of three (or ... More
No Pain, No Gain -- On the Challenges and Promises of Charm StudiesJul 17 2009The observation of $D^0 - \bar D^0$ oscillations has left us in a tantalizing quandary concerning the theoretical interpretation: are they still compatible with the SM or might they require new dynamics (NP)? A comprehensive search for CP violation in ... More
Flavour Dynamics & \cp Violation in the Standard Model: A Crucial Past -- and an Essential FutureJan 31 2007Our knowledge of flavour dynamics has undergone a `quantum jump' since just before the turn of the millenium: direct \cp violation has been firmly {\em established} in $K_L \to \pi \pi$ decays in 1999; the first \cp asymmetry outside $K_L$ decays has ... More
Studying CP Violation -- Chances for a New AllianceJun 26 2002The last three years have seen a phase transition in our knowledge about CP violation: (i) Direct CP violation has been established in $K_L \to \pi \pi$. (ii) The first CP violation outside $K_L$ decays has been observed in $B_d \to \psi K_S$: $<{\rm ... More
The Vietri CodicesJun 23 2002Aug 08 2002Studying heavy flavour physics is driven by multiple motivations: to probe our theoretical control over QCD; enhance our information on gluon and sea quark structure functions; use heavy flavour production as signal for the onset of the quark-gluon plasma; ... More
Charm Physics and the Poor Sleeper's ImpatienceApr 02 2001After a short review of the theoretical tools available to describe heavy flavour physics I sketch the present profile of the weak dynamics of charm hadrons with respect to lifetimes, oscillations and CP violation. I argue that comprehensive studies of ... More
The QCD Perspective on Lifetimes of Heavy-Flavour HadronsAug 31 1995Over the last few years a theoretical treatment for the weak decays of heavy-flavour hadrons has been developed that is genuinely based on QCD. Its methodology is described as it applies to total lifetimes, and the underlying theoretical issues are discussed. ... More
Looking from the East at an Elephant Trotting West: Direct CP Violation in $B^0$ DecaysMar 17 2002Mar 24 2002With the time dependant CP asymmetry in $B_d(t) \to \psi K_S$ well measured, the most powerful method to search for {\em direct} CP violation in $B_d$ decays is to analyze whether the CP asymmetry of other transitions like $B_d(t) \to \pi ^+ \pi ^-, \eta ... More
On A Recent Claim Concerning $τ(D_s)/τ(D^0)$Dec 11 2001Feb 06 2002It has been suggested that the observed $D_s - D^0$ lifetime difference can be `understood' as due to $SU(3)_{Fl}$ breaking in the phase spaces for the exclusive $D^0$ and $D_s$ channels `removing' the need for weak annihilation. It is pointed out that ... More
Charm Physics - Like Botticelli in the Sistine ChapelJul 09 2001After sketching heavy quark expansions as applied to heavy flavour decays I emphasize the relevance of nonperturbative dynamics at the charm scale for exclusive $b\to c$ modes. I address the issue of quark-hadron duality for charm and discuss both the ... More
The Expected, The Promised and The Conceivable -- On CP Violation in Beauty and Charm DecaysDec 05 1994the KM expectations of large CP asymmetries in $B$ decays are reviewed. I describe some observable signatures for the intervention of New Physics and list benchmarks defining the `ultimate' measurements in beauty physics. I also stress the need for dedicated ... More
An efficient and flexible Abel-inversion method for noisy dataAug 25 2016We propose an efficient and flexible method for solving Abel integral equation of the first kind, frequently appearing in many fields of astrophysics, physics, chemistry, and applied sciences. This equation represents an ill-posed problem, thus solving ... More
Superconductivity and Magnetism in BiOCuSJan 13 2010Apr 20 2010BiOCu_{1-y}S was recently reported to superconduct at T=5.8 K at y~0.15. Band structure calculations indicate that stoichiometric BiOCuS is a band insulator. In this paper, I show that hole-doped (whether in the virtual crystal approximation or with actual ... More
Absence of magnetic ordering in NiGa_2S_4Aug 09 2007Triangular-layered NiGa2S4, contrary to intuitive expectation, does not form a noncollinear antiferromagnetic structure, as do isoelectronic NaCrO2 and LiCrO2. Instead, the local magnetic moments remain disordered down to the lowest measured temperature. ... More
Electronic structure and magnetism in the frustrated antiferromagnet LiCrO2Jan 22 2007LiCrO2 is a 2D triangular antiferromagnet, isostructural with the common battery material LiCoO2 and a well-known Jahn-Teller antiferromagnet NaNiO2. As opposed to the latter, LiCrO2 exibits antiferromagnetic exchange in Cr planes, which has been ascribed ... More
Tunneling of Bloch electrons through vacuum barrierDec 04 2000Tunneling of Bloch electrons through a vacuum barrier introduces new physical effects in comparison with the textbook case of free (plane wave) electrons. For the latter, the exponential decay rate in the vacuum is minimal for electrons with the parallel ... More
TOI-150: A transiting hot Jupiter in the TESS southern CVZFeb 26 2019May 27 2019We report the detection of a hot Jupiter ($M_{p}=1.75_{-0.17}^{+0.14}\ M_{J}$, $R_{p}=1.38\pm0.04\ R_{J}$) orbiting a middle-aged star ($\log g=4.152^{+0.030}_{-0.043}$) in the Transiting Exoplanet Survey Satellite (TESS) southern continuous viewing zone ... More
Recent Results from SPLASH: Chemical Abundances and Kinematics of Andromeda's Stellar HaloMar 16 2016Large scale surveys of Andromeda's resolved stellar populations have revolutionized our view of this galaxy over the past decade. The combination of large-scale, contiguous photometric surveys and pointed spectroscopic surveys has been particularly powerful ... More
RXTE observations of Seyfert-2 galaxies: evidence for spectral variabilityAug 18 2000We present a series of RXTE observations of the nearby obscured Seyfert galaxies ESO103-G35, IC5063, NGC4507 and NGC7172. The period of monitoring ranges from seven days for NGC7172 up to about seven months for ESO103-G035. The spectra of all galaxies ... More
CP Asymmetries in Many-Body Final States in Beauty & Charm TransitionsSep 13 2015Dec 06 2015Our community has focused on two-body final states in $B$ & $D$ decays. The SM produces at least the leading source of CP violation in $B$ transitions, none has been established yet in charm decays. It is crucial to measure three- and four-body FS with ... More
Hadronization -- the Unsung Hero rather than the Alleged Villain in the Tale of CP ViolationSep 14 2005The novel successes scored by the Standard Model of High Energy Physics in the last few years concerning heavy flavour dynamics do not weaken the case for `New Physics' around the TeV scale. They do suggest however that one cannot {\em count} on that ... More
`Per Aspera Ad Astra' -- A Short Essay on the Long Quest for CP ViolationNov 10 2004After briefly explaining the special role played by violations of CP and T invariance and their connection with the baryon number of the Universe, I sketch the history of CP violation studies since its totally unexpected discovery in 1964. For about 30 ... More
3- and 4-Body Final States in B, D and tau Decays about Features of New Dynamics with CPT Invariance or "Achaeans outside Troy"Jun 25 2013Aug 08 2013The 'landscape' of fundamental dynamics has changed even for the 'known' matter. The Standard Model has produced at least the leading source of CP violation (CPV) in B decays; the data have not shown CP asymmetries in $D$ transitions. It needs more data ... More
CP Violation in $τ$ Decays at SuperB \& Super-Belle Experiments -- like Finding Signs of Dark MatterOct 10 2012BaBar has found $A_{\rm CP}(\tau^- \to \nu K_S\pi^- [\geq \pi^0]) = (-0.36 \pm 0.23 \pm 0.11)%$ with 2.8 $\sigma$ difference with SM prediction $A_{\rm CP}(\tau^- \to \nu K_S\pi^-) = (0.36 \pm 0.01)%$ based on $K^0 - \bar K^0$ oscillation. Four central ... More
"I Know She Invented Fire, But What Has She Done Recently?" -- On The Future Of Charm PhysicsAug 07 2006Detailed studies of weak charm decays fill an important {\em future} role in high energy physics. Chief among them are: (i) validating the theoretical control achieved over hadronization as a worthwhile goal in its own right; (ii) calibrating our tools ... More
Flavour Dynamics & CP Violation in the SM*: A Tale in Five Parts of Great Successes, Little Understanding -- and Promise for the Future!Jan 20 2006Our knowledge of flavour dynamics has undergone a `quantum jump' since just before the turn of the millenium: direct \cp violation has been firmly {\em established} in $K_L \to \pi \pi$ decays in 1999; the first \cp asymmetry outside $K_L$ decays has ... More
InflationDec 10 2001Inflationary cosmology is reviewed. Particular attention is given to processes of creation.
A study of the effects of preheatingJan 24 1997We review results of a numerical study of resonant inflaton decay in a wide range of realistic models and parameters. Wide enough parametric resonance can withstand the expansion of the Universe, though account for the expansion is very important for ... More
Mossbauer Spectroscopy Determination of iron foreign phases in the Superconducting Systems; RAsFeO1-x, RAsFeO1-xFx and Sr1-xKxFe2As2Jun 25 2008The recently discovered superconducting - spin density wave materials, containing Fe and As, have raised huge interest. However most materials prepared to date, suffer from a varying degree of content of foreign Fe-As phases, Fe2As, FeAs2 and FeAs, which ... More
CaMn$_{2}$Sb$_{2}:$ a fully frustrated classical magnetic systemSep 15 2013We show by means of density functional calculations that CaMn$_{2}$Sb$_{2}$ is very close to a mean-field critical point known for the classical Heisenberg model on the honeycomb lattice. Three entirely different long range ordered magnetic phases become ... More
Correspondence on "Electronic correlations in the iron pnictides"Oct 21 2009I point out that the observed discrepancy between the measured and calculated Drude weights in LaFePO may be caused not only by mass renormalization, but also by a DFT inaccuracy in determining the relative positions of the hole and electron band.
How to calculate the degree of spin polarization in ferromagnets?Dec 19 1998Jun 10 1999Different ways to define and to calculate the degree of spin polarization in a ferromagnet are discussed, particularly with respect to spin-polarized tunneling and Andreev reflection at the boundary between a superconductor and ferromagnet. As an example, ... More
Structural and Electronic Properties of the 2D Superconductor CuS with 1 1/3-valent CopperNov 03 2011Jan 13 2012We present first principle calculations of the structural and electronic properties of the CuS covellite material. Symmetry-lowering structural transition is well reproduced. However, the microscopic origin of the transition is unclear. The calculations ... More
CeMnNi4: an impostor half-metalOct 14 2005Recent experiments show CeMnNi$_{4}$ to have a nearly integer magnetic moment and a relatively large transport spin polarization, as probed by Andreev reflection, suggesting that the material is a half metal or close to it. However, the calculations reported ... More
Testing the wavelength dependence of cosmological redshift down to $Δz \sim 10^{-6}$May 30 2016At the core of the standard cosmological model lies the assumption that the redshift of distant galaxies is independent of photon wavelength. This invariance of cosmological redshift with wavelength is routinely found in all galaxy spectra with a precision ... More
Rectangles in latin squaresFeb 13 2019To get another from a given latin square, we have to change at least 4 entries. We show how to find these entries and how to change them.
The dynamical temperature and the standard mapDec 19 2013Numerical experiments with the standard map at high values of the stochasticity parameter reveal the existence of simple analytical relations connecting the volume and the dynamical temperature of the chaotic component of the phase space.