Results for "A. J. Chromey"

total 338931took 0.21s
The Arizona Radio Observatory CO Mapping Survey of Galactic Molecular Clouds: III. The Serpens Cloud in CO J=2-1 and 13CO J=2-1 EmissionNov 16 2013We mapped 12CO and 13CO J = 2-1 emission over 1.04 square deg of the Serpens molecular cloud with 38 arcsec spatial and 0.3 km/s spectral resolution using the Arizona Radio Observatory Heinrich Hertz Submillimeter telescope. Our maps resolve kinematic ... More
A Search for Pulsed Very High-Energy Gamma Rays from Thirteen Young Pulsars in Archival VERITAS DataApr 19 2019We conduct a search for periodic emission in the very high-energy gamma-ray band (VHE; E > 100 GeV) from a total of 13 pulsars in an archival VERITAS data set with a total exposure of over 450 hours. The set of pulsars includes many of the brightest young ... More
VERITAS observations of the BL Lac object TXS 0506+056Jul 12 2018On 2017 September 22, the IceCube Neutrino Observatory reported the detection of the high-energy neutrino event \icnu, of potential astrophysical origin. It was soon determined that the neutrino direction was consistent with the location of the gamma-ray ... More
Direct measurement of stellar angular diameters by the VERITAS Cherenkov TelescopesApr 12 2019The angular size of a star is a critical factor in determining its basic properties. Direct measurement of stellar angular diameters is difficult: at interstellar distances stars are generally too small to resolve by any individual imaging telescope. ... More
Detecting "Temperate" Jupiters: The Prospects of Searching for Transiting Gas Giants in Habitability ZonesFeb 18 2008This paper investigates the effects of observing windows on detecting transiting planets by calculating the fraction of planets with a given period that have zero, one (single), two (double), or $\ge$3 (multiple) transits occurring while observations ... More
Dust Streamers in the Virgo Galaxy M86 from Ram Pressure Stripping of its Companion VCC 882May 11 2000The giant elliptical galaxy M86 in Virgo has a ~28 kpc long dust trail inside its optical halo that points toward the nucleated dwarf elliptical galaxy, VCC 882. The trail seems to be stripped material from the dwarf. Extinction measurements suggest that ... More
Periastron Observations of TeV Gamma-Ray Emission from a Binary System with a 50-year PeriodOct 11 2018We report on observations of the pulsar / Be star binary system PSR J2032+4127 / MT91 213 in the energy range between 100 GeV and 20 TeV with the VERITAS and MAGIC imaging atmospheric Cherenkov telescope arrays. The binary orbit has a period of approximately ... More
VERITAS and Fermi-LAT observations of new HAWC sourcesAug 30 2018The HAWC (High Altitude Water Cherenkov) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100~GeV) gamma-ray sources based on 507 days of observation. Among these, there are nineteen sources that are not associated ... More
Type-II Bose-Mott insulatorsJul 02 2012Sep 25 2012The Mott insulating state formed from bosons is ubiquitous in solid He-4, cold atom systems, Josephson junction networks and perhaps underdoped high-Tc superconductors. We predict that close to the quantum phase transition to the superconducting state ... More
A fractal set from the binary reflected Gray codeOct 14 2005The permutation associated with the decimal expression of the binary reflected Gray code with $N$ bits is considered. Its cycle structure is studied. Considered as a set of points, its self-similarity is pointed out. As a fractal, it is shown to be the ... More
Substrate concentration dependence of the diffusion-controlled steady-state rate constantDec 20 2004The Smoluchowski approach to diffusion-controlled reactions is generalized to interacting substrate particles by including the osmotic pressure and hydrodynamic interactions of the nonideal particles in the Smoluchoswki equation within a local-density ... More
Tests of mode coupling theory in a simple model for two-component miscible polymer blendsAug 06 2007Sep 26 2007We present molecular dynamics simulations on the structural relaxation of a simple bead-spring model for polymer blends. The introduction of a different monomer size induces a large time scale separation for the dynamics of the two components. Simulation ... More
Symplectic torus actions with coisotropic principal orbitsNov 28 2005Jan 10 2006In this paper we completely classify symplectic actions of a torus $T$ on a compact connected symplectic manifold $(M, \sigma)$ when some, hence every, principal orbit is a coisotropic submanifold of $(M, \sigma)$. That is, we construct an explicit model, ... More
A fast and accurate algorithm for solving Bernstein-Vandermonde linear sytemMay 22 2006Sep 27 2006A fast and accurate algorithm for solving a Bernstein-Vandermonde linear system is presented. The algorithm is derived by using results related to the bidiagonal decomposition of the inverse of a totally positive matrix by means of Neville elimination. ... More
Origin of n- and p-type conductivity in undoped $α$-PbO: role of defectsApr 16 2013Nov 05 2013The first principles calculations (GGA) have been applied to study the crystallographic defects in $\alpha$-PbO in order to understand an origin of $n$- and $p$-type conductivity in otherwise undoped $\alpha$-PbO. It was found that deposition in the oxygen-deficient ... More
Comment on "Superconducting phases in the presence of Coulomb interaction: From weak to strong correlations''Mar 24 1999We examine the paper basic equations of T. Doma\'nski and K.I. Wysoki\'nski [Phys. Rev. B {\bf 59}, 173 (1999)], who calculated the critical superconducting temperature, T_c, in function of Coulomb correlations (U) for s- and d-wave order parameter symmetries. ... More
Comment on ``Relativistic cluster dynamics of nucleons and mesons. II. Formalism and examples''Apr 07 1995In a recent paper [Phys.\ Rev.\ C{\bf 49}, 2142 (1994)], Haberzettl presented cluster N-body equations for arbitrarily large systems of nucleons and mesons. Application to the three-nucleon system is claimed to yield a new kind of three-nucleon force. ... More
Dark Matter Halo Mergers I: Dependence on Environment & Redshift EvolutionFeb 26 2009This paper presents a study of the specific merger rate as a function of group membership, local environment, and redshift in a very large, $500h^{-1} Mpc$, cosmological N-body simulation, the \textit{Millennium Simulation}. The goal is to provide environmental ... More
Does Dark Matter Exist?Sep 05 2000The success of the Lambda-CDM model on large scales does not extend down to galaxy scales. We list a dozen problems of the dark matter hypothesis, some of which arise in specific models for the formation of structure in the universe, while others are ... More
Anisotropic pressure in strange quark matter under the presence of a strong magnetic fieldOct 11 2012Jan 03 2013Thermodynamic properties of strange quark matter in strong magnetic fields $H$ up to $10^{20}$ G are considered within the MIT bag model at zero temperature implying the constraints of total baryon number conservation, charge neutrality and chemical equilibrium. ... More
Spin polarization phenomena in dense neutron matter at a strong magnetic fieldNov 04 2010Spin polarized states in neutron matter at strong magnetic fields up to $10^{18}$ G are considered in the model with the Skyrme effective interaction. Analyzing the self-consistent equations at zero temperature, it is shown that a thermodynamically stable ... More
Structural and electronic changes of pentacene induced by potassium dopingFeb 14 2017Potassium is introduced into the crystalline herringbone structure of pentacene searching for a compound showing metallic electronic transport properties and, hopefully, superconductivity at small enough temperatures. Several possible structures for stoichiometric ... More
The one-loop elastic coefficients for the Helfrich membrane in higher dimensionsMay 18 2004Jan 26 2005Using a covariant geometric approach we obtain the effective bending couplings for a 2-dimensional rigid membrane embedded into a $(2+D)$-dimensional Euclidean space. The Hamiltonian for the membrane has three terms: The first one is quadratic in its ... More
Ultrafast single electron spin manipulation in 2D semiconductor quantum dots with optimally controlled time-dependent electric fields through spin-orbit couplingOct 23 2014We have studied theoretically the possibility of ultra-fast manipulation of a single electron spin in 2D semiconductor quantum dots, by means of high-frequency time-dependent electric fields. The electron spin degree of freedom is excited through spin-orbit ... More
Schubert varieties and cycle spacesApr 02 2002Oct 02 2002Complex geometric properties of the orbits of a non-compact real form $G_0$ in a flag manifold $Z=G/Q$ of a complex semi-simple groups $G=G_0^\mathbb C$ are studied. Schubert varieties are used to construct a complex submanifold with optimal slice properties ... More
Guiding-center recursive Vlasov and Lie-transform methods in plasma physicsMar 25 2009The gyrocenter phase-space transformation used to describe nonlinear gyrokinetic theory is rediscovered by a recursive solution of the Hamiltonian dynamics associated with the perturbed guiding-center Vlasov operator. The present work clarifies the relation ... More
Study of the glass transition in the amorphous interlamellar phase of highly crystallized poly(ethylene terephthalate)Jul 21 2009Jun 01 2010Poly(ethylene terephthalate) (PET) is a semi--crystalline polymer that can be crystallized to different degrees heating from the amorphous state. Even when primary crystallization has been completed, secondary crystallization can take place with further ... More
A consistent formalism for the Thomas-Ehrman Level DisplacementApr 26 2007Usage of the Thomas-Ehrman Level Displacement formalism has been examined. Mistakes and inconsistencies are found in several papers, being repeated in subsequent works. Here, we present a complete formalism with a consistent set of definitions. Full algorithms ... More
Electronic Transmission Through Metallic Nanowires: Generalized Scattering Matrix ApproachDec 14 2000An easy to implement and powerful method for the solution of 3D scattering problems that can be well described by Helmholtz equation is presented. The matrix algebra used provides excellent stability versus the number of junctions as well as great computational ... More
Volume fluctuations and linear response in a simple model of compactionMar 01 2007Jul 10 2007By means of a simple model system, the total volume fluctuations of a tapped granular material in the steady state are studied. In the limit of a system with a large number of particles, they are found to be Gaussian distributed, and explicit expressions ... More
Slow logarithmic relaxation in models with hierarchically constrained dynamicsJun 27 2000Nov 06 2000A general kind of models with hierarchically constrained dynamics is shown to exhibit logarithmic anomalous relaxation, similarly to a variety of complex strongly interacting materials. The logarithmic behavior describes most of the decay of the response ... More
The Kovacs effect: a master equation analysisNov 20 2009Jan 14 2010The Kovacs or crossover effect is one of the peculiar behaviours exhibited by glasses and other complex, slowly relaxing systems. Roughly it consists in the non-monotonic relaxation to its equilibrium value of a macroscopic property of a system evolving ... More
Closed model for granular compaction under weak tappingOct 30 2003A one dimensional lattice model is formulated to study tapping dynamics and the long time steady distribution in granular media. The dynamics conserves the number of particles in the system, and density changes are associated to the creation and destruction ... More
An exact algorithm for spin correlation functions of the two dimensional +/-J Ising spin glass in the ground stateApr 18 2005We introduce an exact algorithm for the computation of spin correlation functions for the two dimensional +/-J Ising spin glass in the ground state. Unlike with the transfer matrix method, there is no particular restriction on the shape of the lattice ... More
The nature of ZZ branesJul 23 2007Dec 04 2007In minimal non-critical string theory we show that the principal (r,s) ZZ brane can be viewed as the basic (1,1) ZZ boundary state tensored with the (r,s) Cardy boundary state. In this sense there exists only one ZZ boundary state, the basic (1,1) boundary ... More
Particle Energy And Acceleration Efficiencies In Highly Relativistic ShocksJan 15 2001Jan 23 2001In this paper we present an investigation of numerical Monte Carlo simulations of the diffusive shock acceleration in the test particle limit. Very high gamma flow astrophysical plasmas, have been used, from $\gamma_{up}$ $\sim50$ up to $\gamma_{up}$ ... More
Reduced phase space and toric variety coordinatizations of Delzant spacesApr 03 2007In this note we describe the natural coordinatizations of a Delzant space defined as a reduced phase space (symplectic geometry view-point) and give explicit formulas for the coordinate transformations. For each fixed point of the torus action on the ... More
Higgs triplet effects in purely leptonic processesNov 11 1995We consider the effect of complex Higgs triplets on purely leptonic processes and survey the experimental constraints on the mass and couplings of their single and double charge members. Present day experiments tolerate values of the Yukawa couplings ... More
Self-passivation of vacancies in α-PbOFeb 06 2013We introduce a self-passivation of single lead (Pb) and oxygen (O) vacancies in the \alpha-PbO compound through formation of a Pb-O vacancy pair. The preferential mechanism for pair formation involves initial development of the single Pb vacancy which, ... More
Compilation of relations for the antisymmetric tensors defined by the Lie algebra cocycles of $su(n)$Jun 27 2000May 17 2001This paper attempts to provide a comprehensive compilation of results, many new here, involving the invariant totally antisymmetric tensors (Omega tensors) which define the Lie algebra cohomology cocycles of $su(n)$, and that play an essential role in ... More
Scalar-Tensor Quantum Gravity in Two DimensionsJan 12 1992Jan 24 1992We discuss some classical and quantum properties of 2d gravity models involving metric and a scalar field. Different models are parametrized in terms of a scalar potential. We show that a general Liouville-type model with exponential potential and linear ... More
Domain Walls in Superfluid 3He-BAug 20 2004We consider domain walls between regions of superfluid 3He-B in which one component of the order parameter has the opposite sign in the two regions far from one another. We report calculations of the order parameter profile and the free energy for two ... More
Theory of Transition Temperature of Magnetic Double PerovskitesJun 13 2000We formulate a theory of double perovskite coumpounds such as Sr$_2$FeReO$_6$ and Sr$_2$FeMoO$_6$ which have attracted recent attention for their possible uses as spin valves and sources of spin polarized electrons. We solve the theory in the dynamical ... More
Dynamical Mean-Field Theory of Electron-Phonon Interactions in Correlated Systems: Application to Isotope Effects on Electronic PropertiesNov 26 2001Feb 09 2002We use a recently developed formalism (combining an adiabatic expansion and dynamical mean-field theory) to obtain expressions for isotope effects on electronic properties in correlated systems. As an example we calculate the isotope effect on electron ... More
String Theory and the Donaldson PolynomialAug 26 1991It is shown that the scattering of spacetime axions with fivebrane solitons of heterotic string theory at zero momentum is proportional to the Donaldson polynomial.
Proposition Algebra with Projective LimitsJul 23 2008Feb 19 2010Sequential propositional logic deviates from ordinary propositional logic by taking into account that during the sequential evaluation of a propositional statement,atomic propositions may yield different Boolean values at repeated occurrences. We introduce ... More
Finite temperature effects on anisotropic pressure and equation of state of dense neutron matter in an ultrastrong magnetic fieldJan 03 2013Jan 04 2013Spin polarized states in dense neutron matter with recently developed Skyrme effective interaction (BSk20 parametrization) are considered in the magnetic fields $H$ up to $10^{20}$ G at finite temperature. In a strong magnetic field, the total pressure ... More
Near field and far field scattering of surface plasmon polaritons by one-dimensional surface defectsApr 23 1999A rigorous formulation for the scattering of surface plasmon polaritons (SPP) from a one-dimensional surface defect of any shape that yields the electromagnetic field in the vacuum half-space above the vacuum-metal interface is developed by the use of ... More
On algorithmic unsolvability of the problem embeddability of algebraic varieties over a field of characteristic zeroDec 05 2018Jan 21 2019We show that for two afii varieties over an arbitrary field of characteristic zero, there is no general form of an algorithm for checking the presence of an embedding of one algebraic variety in another. Moreover, we establish this for affine varieties ... More
On algorithmic unsolvability of the problem embeddability of algebraic varieties over a field of characteristic zeroDec 05 2018Jun 05 2019We show that for two afii varieties over an arbitrary field of characteristic zero, there is no general form of an algorithm for checking the presence of an embedding of one algebraic variety in another. Moreover, we establish this for affine varieties ... More
Probing Ion-Ion and Electron-Ion Correlations in Liquid Metals within the Quantum Hypernetted Chain ApproximationSep 07 1999We use the Quantum Hypernetted Chain Approximation (QHNC) to calculate the ion-ion and electron-ion correlations for liquid metallic Li, Be, Na, Mg, Al, K, Ca, and Ga. We discuss trends in electron-ion structure factors and radial distribution functions, ... More
A Rainich-like approach to the Killing-Yano tensorsDec 20 2002Jan 17 2003The Rainich problem for the Killing-Yano tensors posed by Collinson \cite{col} is solved. In intermediate steps, we first obtain the necessary and sufficient conditions for a 2+2 almost-product structure to determine the principal 2--planes of a skew-symmetric ... More
Single particle nonlocality with completely independent reference statesJul 01 2008We describe a scheme to demonstrate the nonlocal properties of a single particle by showing a violation of Bell's inequality. The scheme is experimentally achievable as the only inputs are number states and mixed states, which serve as references to `keep ... More
A follow-up to 'Does Nature abhor a logarithm?' (and apparently she doesn't)Nov 15 2004This letter contains a brief discussion on the leading-order canonical correction to the Bekenstein-Hawking (black hole) entropy. In particular, we address some recent criticism directed at an earlier commentary.
Bad News on the BraneMay 24 2002Sep 26 2002There has been substantial interest in obtaining a quantum-gravitational description of de Sitter space. However, any such attempts have encountered formidable obstacles, and new philosophical directions may be in order. One possibility, although somewhat ... More
Reissner-Nordstrom Near Extremality from a Jackiw-Teitelboim PerspectiveNov 10 2001Nov 21 2001In this paper, we investigate the near-extremal thermodynamics of the Reissner-Nordstrom (RN) black hole. Our methodology is based on a duality that exists between the near-horizon geometry of the near-extremal RN sector and Jackiw-Teitelboim (JT) theory. ... More
Radiation via Tunneling from a de Sitter Cosmological HorizonJul 29 2002Sep 26 2002Hawking radiation can usefully be viewed as a semi-classical tunneling process that originates at the black hole horizon. The same basic premise should apply to de Sitter background radiation, with the cosmological horizon of de Sitter space now playing ... More
Quantum-Corrected Cardy Entropy for Generic 1+1-Dimensional GravityJan 14 2002Jan 18 2002Various studies have explored the possibility of explaining the Bekenstein-Hawking (black hole) entropy by way of some suitable state-counting procedure. Notably, many of these treatments have used the well-known Cardy formula as an intermediate step. ... More
Anisotropy in the angular distribution of the long gamma-ray bursts?Mar 10 2003The gamma-ray bursts detected by the BATSE instrument may be separated into "short", "intermediate" and "long" subgroups. Previous statistical tests found an anisotropic sky-distribution on large angular scales for the intermediate subgroup, and probably ... More
Wedge Diffraction as an Instance of Radiative ShieldingOct 06 2016The celebrated Sommerfeld wedge diffraction solution is reexamined from a null interior field perspective. Exact surface currents provided by that solution, when considered as disembodied half-plane laminae radiating into an ambient, uniform space both ... More
Jump conditions for strings and sheets from an action principleJun 14 2014Mar 26 2015I present conditions for compatibility of velocities, conservation of mass, and balance of momentum and energy across moving discontinuities in inextensible strings and sheets of uniform mass density. The balances are derived from an action with a time-dependent, ... More
Low-energy eta-nuclear scattering parametres vs. binding properties in light nucleiDec 27 2013The connection of the binding energy and width of possible bound eta-mesic states is given to the complex scattering length for s-states in the hope that, with knowledge of the final state interaction this could be useful in searches of these states. ... More
Smallness of the imaginary part of the eta-nucleus scattering lengthAug 10 2005In two recent analyses of eta meson production a very small imaginary part was obtained for the eta-He3 scattering length, which is in contradiction with most theoretical predictions. In this report a plausible explanation is given to this unexpectedly ... More
Bosonization in the two-channel Kondo modelJun 10 1996The bosonization of the $S=1/2$ anisotropic two-channel Kondo model is shown to yield two equivalent representations of the original problem. In a straight forward extension of the Emery-Kivelson approach, the interacting resonant level model previously ... More
Balance of baryon number in the quark coalescence modelAug 07 2005The charge and baryon balance functions are studied in the coalescence hadronization mechanism of quark-gluon plasma. Assuming that in the plasma phase the $q\bar{q}$ pairs form uncorrelated clusters whose decay is also uncorrelated, one can understand ... More
An aspherical 5-manifold with perfect fundamental groupMay 16 2013Sep 15 2013We construct aspherical closed orientable 5-manifolds with perfect fundamental group. This completes part of our study (with D.H.Kochloukova and I.Lima) of $PD_n$-groups with pro-$p$ completion a pro-$p$ Poincar\'e duality group of dimension $\leq{n-2}$. ... More
On the Binary Nature of Dust-encircled BD+20 307Apr 10 2008Apr 16 2008Three epochs of high resolution spectra of the star BD+20 307 show that it is a short period (~3.5 day) spectroscopic binary of two nearly identical stars. Surprisingly, the two stars, though differing in effective temperature by only ~250 K and having ... More
LOFAR, a new low frequency radio telescopeSep 19 2003LOFAR, the Low Frequency Array, is a large radio telescope consisting of approximately 100 soccer-field sized antenna stations spread over a region of 400 km in diameter. It will operate at frequencies from ~10 to 240 MHz, with a resolution at 240 MHz ... More
Excited nucleon electromagnetic form factors from broken spin-flavor symmetryFeb 27 2010A group theoretical derivation of a relation between the N --> Delta charge quadrupole transition and neutron charge form factors is presented.
Dynamical variables in Gauge-Translational GravityJul 02 2010Assuming that the natural gauge group of gravity is given by the group of isometries of a given space, for a maximally symmetric space we derive a model in which gravity is essentially a gauge theory of translations. Starting from first principles we ... More
Quantum Fluctuation Effects on Nuclear Fragment FormationNov 01 1996Multifragmentation in Au+Au collisions is investigated at incident energies in the range 100-400 MeV per nucleon by means of a recently developed quantal Langevin model. The inclusion of quantum fluctuations enhances the average multiplicity of intermediate ... More
Higher Dimensional Elko TheoryJul 03 2013Jul 07 2014We show that the so called Elko equation can be derived from a 5-dimensional Dirac equation. We argue that this result can be relevant for dark matter and cosmological scenarios. We generalize our procedure to higher dimensions.
Mass and radius determination for the neutron star in X-ray burst source 4U/MXB 1728-34Jan 04 2006We analyzed archival X-ray spectra of MXB 1728-34 obtained in 1996-99 by the Proportional Counter Array on board of the RXTE satellite. X-ray spectra were fitted to our extensive grids of model atmosphere spectra to determine the effective temperature ... More
Current-induced spin polarization and spin-orbit torque in grapheneMay 11 2015Oct 11 2015Using the Green function formalism we calculate a current-induced spin polarization of weakly magnetized graphene with Rashba spin-orbit interaction. In a general case, all components of the current-induced spin polarization are nonzero, contrary to the ... More
Extended Self-Dual Configurations as Stable Exact Solutions in Born-Infeld TheoryJul 10 2000A class of exact solutions to the Born-Infeld field equations, over manifolds of any even dimension, is constructed. They are an extension of the self-dual configurations. They are local minima of the action for riemannian base manifolds and local minima ... More
Classical Analytical Mechanics and Entropy ProductionJan 08 2007The usual canonical Hamiltonian or Lagrangian formalism of classical mechanics applied to macroscopic systems describes energy conserving adiabatic motion. If irreversible diabatic processes are to be included, then the law of increasing entropy must ... More
Gauge fixing in higher derivative field theoriesMar 10 1994Higher Derivative (HD) Field Theories can be transformed into second order equivalent theories with a direct particle interpretation. In a simple model involving abelian gauge symmetries we examine the fate of the possible gauge fixings throughout this ... More
Temperature dependence of surface reconstructions of Au on Pd(110)Mar 30 1995Surface reconstructions of Au film on Pd(110) substrate are studied using a local Einstein approximation to quasiharmonic theory with the Sutton-Chen interatomic potential. Temperature dependent surface free energies for different coverages and surface ... More
Multichannel chiral approach for kaonic hydrogenOct 18 2007Oct 22 2007We present an exact solution to the $K^{-}$-proton bound state problem formulated in the momentum space. The 1s level characteristics of the kaonic hydrogen are described together with the available low energy $\bar{K}N$ data.
Chiral model for $\bar{K}N$ interactions and its pole contentNov 09 2010We use chirally motivated effective meson-baryon potentials to describe the low energy $\bar{K}N$ data including the characteristics of kaonic hydrogen. Our results are examined in comparison with other approaches based on the unitarity and dispersion ... More
Kaonic hydrogen versus the $K^{-}p$ low energy dataNov 30 2007Jan 18 2008We present an exact solution to the $K^{-}$-proton bound state problem formulated in the momentum space. The 1s level characteristics of the kaonic hydrogen are computed simultaneously with the available low energy $K^{-}p$ data. In the strong interaction ... More
Whither Correlated Electron Theory?Dec 31 2001This is the text of the 'Theory' opening talk at the 2001 Strongly Correlated Electron Systems conference. It contains opinions about some of the outstanding scientific challenges facing the theory side of the correlated electrons field.
Tight informationally complete quantum measurementsApr 07 2006Oct 11 2006We introduce a class of informationally complete positive-operator-valued measures which are, in analogy with a tight frame, "as close as possible" to orthonormal bases for the space of quantum states. These measures are distinguished by an exceptionally ... More
Updating the Unitarity Triangle: Top Quark Mass Versus Nonperturbative UncertaintiesJul 05 1994We summarize the present knowledge on the non-perturbative hadronic inputs needed in the analysis of $B^0$-$\bar B^0$ mixing and the CP-violating parameter $\varepsilon$ of the $K^0$-$\bar K^0$ system. Using this information, together with the recently ... More
Lorentz Symmetry breaking studies with photons from astrophysical observationsJul 28 2010Feb 21 2011Lorentz Invariance Violation (LIV) may be a good observational window on Quantum Gravity physics. Within last few years, all major Gamma-ray experiments have published results from the search for LIV with variable astrophysical sources: gamma-ray bursts ... More
Dynamics of Disks and WarpsJun 24 2010Oct 18 2011This chapter reviews theoretical work on the stellar dynamics of galaxy disks. All the known collective global instabilities are identified, and their mechanisms described in terms of local wave mechanics. A detailed discussion of warps and other bending ... More
A Recent Lindblad Resonance in the Solar NeighbourhoodJan 28 2010Jul 06 2010Stars in the solar neighbourhood do not have a smooth distribution of velocities. Instead, the distribution of velocity components in the Galactic plane manifests a great deal of kinematic substructure. Here I present an analysis in action-angle variables ... More
Dark Matter Density in Disk GalaxiesJul 12 2008I show that the predicted densities of the inner dark matter halos in LCDM models of structure formation appear to be higher than estimates from real galaxies and constraints from dynamical friction on bars. This inconsistency would not be a problem for ... More
Bar-halo Friction in Galaxies I: Scaling LawsJul 26 2004Sep 28 2005It has been known for some time that rotating bars in galaxies slow due to dynamical friction against the halo. However, recent attempts to use this process to place constraints on the dark matter density in galaxies and possibly also to drive dark matter ... More
What is the Evidence for Dark Matter?Jan 20 2004Jan 22 2004Newtonian mechanics indicates that galaxies and galaxy clusters are much more massive than we would have guessed from their luminosities, with the discrepancy being generally attributed to dark matter halos. An alternative hypothesis is that accelerations ... More
Is a Simple Collisionless Relic Dark Matter Particle Ruled Out?Apr 26 2000Jun 28 2000The central densities of dark matter (DM) halos are much lower than predicted in cold DM models of structure formation. Confirmation that they have cores with a finite central density would allow us to rule out many popular types of collisionless particle ... More
Galaxy dynamics by N-body simulationDec 09 1996Jan 10 1997I compare various popular and unpopular techniques for simulating large collisionless stellar systems. I give a quantitative comparison of the raw cpu times required for five separate codes, including tree codes and basis function expansions, which demonstrate ... More
Benchmarks for Parity Games (extended version)Jul 11 2014Jan 16 2015We propose a benchmark suite for parity games that includes all benchmarks that have been used in the literature, and make it available online. We give an overview of the parity games, including a description of how they have been generated. We also describe ... More
Heavy Quarkonium and nonperturbative correctionsFeb 20 1996Jul 31 1996We analyse the possible existence of non-perturbative contributions in heavy $\bar Q Q$ systems ($\bar Q$ and $Q$ need not have the same flavour) which cannot be expressed in terms of local condensates. Starting from QCD, with well defined approximations ... More
Generating and using truly random quantum states in MathematicaFeb 22 2011Oct 19 2011The problem of generating random quantum states is of a great interest from the quantum information theory point of view. In this paper we present a package for Mathematica computing system harnessing a specific piece of hardware, namely Quantis quantum ... More
Six dimensional QCD at two loopsDec 14 2015We construct the six dimensional Quantum Chromodynamics (QCD) Lagrangian in a linear covariant gauge and subsequently renormalize it at two loops in the MSbar scheme. The coupling constant corresponding to the gauge interaction is asymptotically free ... More
Recent results for Yang-Mills theory restricted to the Gribov regionNov 22 2007We summarize recent results for the Gribov-Zwanziger Lagrangian which includes the effect of restricting the path integral to the first Gribov region. These include the two loop MSbar and one loop MOM gap equations for the Gribov mass.
One loop gluon form factor and freezing of alpha_s in the Gribov-Zwanziger QCD LagrangianMay 08 2006We use the Gribov-Zwanziger Lagrangian in QCD to evaluate the one loop correction to the gluon propagator as a function of the Gribov volume and verify that the propagator vanishes in the infrared limit. Using the corresponding correction to the Faddeev-Popov ... More
QCD and QED renormalization group functions - a large N_f approachApr 29 1996The large N_f self-consistency programme is reviewed. As an application the QCD beta-function is computed at O(1/N_f) and the anomalous dimensions of polarized twist-2 singlet operators are determined at the same order.
One loop renormalization of the non-local gauge invariant operator min_U (A^U_mu)^2 in QCDJun 11 2007We compute the one loop anomalous dimension of the gauge invariant dimension two operator min_U (A^U_mu)^2, where U is an element of the gauge group, by exploiting Zwanziger's expansion of the operator in terms of gauge invariant non-local n leg operators. ... More