Results for "Victor Lazarian"
total 5711took 0.11s
Obtaining Spectra of Turbulent Velocity from ObservationsNov 06 2008We discuss a long-standing problem of how turbulence can be studied using observations of Doppler broadened emission and absorption lines. The focus of the present review is on two new techniques, the Velocity-Channel Analysis (VCA), which makes use of ... More Grain Alignment and CMB Polarization StudiesNov 06 2008Polarized microwave emission from dust is an important foreground that may contaminate polarized CMB studies unless carefully accounted for. Modeling of polarization from dust requires a quantitative understanding of grain alignment. I review the current ... More Physics and Chemistry of Purcell's AlignmentJan 17 1995Paramagnetic alignment of suprathermally rotating grains is discussed in view of recent progress in understanding subtle processes taking place over grain surface. It is shown that in typical ISM conditions, grains with surfaces of amorphous H$_{2}$O ... More Grain Alignment, Polarization and Magnetic FieldsAug 02 2006Aligned non-spherical dust particles polarize starlight passing through the dust cloud. They also emit polarized far infrared and sub-mm radiation. Substantial progress in understanding of grain alignment theory makes the interpretation of the polarized ... More Paramagnetic alignment of thermally rotating dustFeb 16 1997Paramagnetic alignment of thermally rotating oblate dust grains is studied analytically for finite ratios of grain to gas temperatures. For such ratios, the alignment of angular momentum J in respect to the grain axis of maximal inertia is only partial. ... More Davis-Greenstein alignment of non-spherical grainsMay 07 1995Paramagnetic alignment of non-spherical dust grains rotating at thermal velocities is studied. The analytical solution is found for the alignment measure of oblate grains. Perturbative approach is used for solving the problem. It is shown that even the ... More Grain Alignment by Radiative TorquesDec 03 2008Grain alignment is a notoriously difficult problem, that is extremely rich in underlying physics. The long history of attempts theoretical handling of the problem resulted in rather sceptical approach to the theory on the part of some polarimetry practitioners. ... More Tracing Magnetic Fields with Aligned GrainsJul 05 2007Jul 05 2007Magnetic fields play a crucial role in various astrophysical processes, including star formation, accretion of matter, transport processes (e.g., transport of heat), and cosmic rays. One of the easiest ways to determine the magnetic field direction is ... More Diffusion Processes in Turbulent Magnetic FieldsJul 04 2007Jul 05 2007We study of the effect of turbulence on diffusion processes within magnetized medium. While we exemplify our treatment with heat transfer processes, our results are quite general and are applicable to different processes, e.g. diffusion of heavy elements. ... More Turbulence Statistics from Spectral Line ObservationsMay 28 2005Turbulence is a crucial component of dynamics of astrophysical fluids dynamics, including those of ISM, clusters of galaxies and circumstellar regions. Doppler shifted spectral lines provide a unique source of information on turbulent velocities. We discuss ... More Grain Alignment in Molecular CloudsNov 17 2003One of the most informative techniques of studying magnetic fields in molecular clouds is based on the use of starlight polarization and polarized emission arising from aligned dust. How reliable the interpretation of the polarization maps in terms of ... More Turbulence in Atomic HydrogenApr 02 1998Understanding the properties of interstellar turbulence is a great intellectual challenge and the urge to solve this problem is partially motivated by a necessity to explain the star formation mystery. This review deals with a recently suggested inversion ... More Alignment of suprathermally rotating grainsAug 15 1995It is shown, that mechanical alignment can be efficient for suprathermally rotating grains, provided that they drift with supersonic velocities. Such a drift should be widely spread due to both Alfv\'{e}nic waves and ambipolar diffusion. Moreover, if ... More Mechanical alignment of suprathermally rotating grainsMay 01 1995It is shown that mechanical alignment of grains can be efficient for grains rotating suprathermally, i.e. with kinetic energy substantially exceeding $k$ (the Boltzmann constant) over any temperature in the system. The paper studies suprathermal rotation ... More SINS of Viscosity Damped TurbulenceAug 02 2006Oct 26 2006The problems with explaining the Small Ionized and Neutral Structures (SINS) appealing to turbulence stem from inefficiency of the Kolmogorov cascade in creating large fluctuations at sufficiently small scales. However, other types of cascades are possible. ... More Enhancement and suppression of heat transfer by MHD turbulenceAug 02 2006Aug 03 2006We study of the effect of turbulence on heat transfer within magnetized plasmas for energy injection velocities both larger and smaller that the Alfven speed. We find that in the latter regime the heat transfer is partially suppressed, while in the former ... More Polarized Microwave Radiation from DustDec 30 2000Observations of cosmic microwave background in the range 10-90 GHz have revealed an anomalous foreground component well correlated with 12 \mum, 60 \mum and 100 \mum emission from interstellar dust. As the recent cross-correlation analysis of WHAM H\alpha ... More Instance Segmentation by Deep ColoringJul 26 2018We propose a new and, arguably, a very simple reduction of instance segmentation to semantic segmentation. This reduction allows to train feed-forward non-recurrent deep instance segmentation systems in an end-to-end fashion using architectures that have ... More Turbulence Spectra from Doppler-shifted Spectral LinesOct 26 2006Turbulence is a key element of the dynamics of astrophysical fluids, including those of interstellar medium, clusters of galaxies and circumstellar regions. Turbulent motions induce Doppler shifts of observable emission and absorption lines. In the review ... More Statistics of Turbulence from Spectral-Line Data CubesJan 01 2000Emission in spectral lines can provide unique information on interstellar turbulence. Doppler shifts due to supersonic motions contain information on turbulent velocity field which is otherwise difficult to measure. However, the problem of separation ... More Gold alignment & internal dissipationFeb 16 1997The measures of mechanical alignment were obtained for both prolate and oblate grains when their temperature is comparable with grain kinetic energy devided by k, the Boltzmann constant. For such grains, the alignment of angular momentum, J, with the ... More Paramagnetic alignment of fractal grainsAug 23 1994Paramagnetic alignment of fractal suprathermally rotating grains is discussed. It is shown that if the concentration of H$_{2}$formation sites is low and resurfacing is active, fractal structure of grains enhances their alignment. Studying the influence ... More The meaning of concurrent programsOct 07 2008The semantics of assignment and mutual exclusion in concurrent and multi-core/multi-processor systems is presented with attention to low level architectural features in an attempt to make the presentation realistic. Recursive functions on event sequences ... More Astrophysical Data and Conformal Unified TheoryOct 31 2002Astrophysical data reformulated in the units of the relative Paris meter and running Planck mass are used for restoration of a conformal version of the unified theory where the absolute Planck mass belongs to ordinary initial data (like the absolute Ptolemaeus ... More Non stationary nucleation: the model with averaged velocityFeb 01 2013A new model to calculate the rate of nucleation is formulated. This model is based on the classical nucleation theory but considers also vapor depletion around the formed embryo. The key characteristic which arises in frames of this theory is the mean ... More Late periods of the condensation processNov 15 2010The full evolution during the late periods of the condensation process is described in the analytical form. The process is split into several periods and for every period the simple approximate solution is given. Non stationary nucleation: the model with minimal environmentJan 06 2013A new model to calculate the rate of nucleation is formulated. This model is based on the classical nucleation theory but considers also vapor depletion around the formed embryo. As the result the free energy has to be recalculated which brings a new ... More Multicomponent nonisothermal nucleation. 1. Kinetic equationSep 03 1999The first part of the theory for the multicomponent nonisothermal nucleation is presented. On the base of analysis of the elementary acts of interation between an embryo and environment the kinetic equation is derived. This equation will be solved later ... More Super-connections and non-commutative geometryJun 14 1996Aug 21 1996We show that Quillen's formalism for computing the Chern character of the index using superconnections extends to arbitrary operators with functional calculus. We thus remove the condition that the operators have, up to homotopy, a gap in the spectrum. ... More On H.Weyl and H.Minkowski PolynomialsFeb 06 2007Feb 14 2007We introduce certain polynomials, so-called H.Weyl and H.Minkowski polynomials, which have a geometric origin. The location of roots of these polynomials is studied. Linear Datalog and Bounded Path Duality of Relational StructuresApr 07 2005Jun 28 2005In this paper we systematically investigate the connections between logics with a finite number of variables, structures of bounded pathwidth, and linear Datalog Programs. We prove that, in the context of Constraint Satisfaction Problems, all these concepts ... More Generalized Majority-Minority Operations are TractableSep 19 2006Sep 27 2006Generalized majority-minority (GMM) operations are introduced as a common generalization of near unanimity operations and Mal'tsev operations on finite sets. We show that every instance of the constraint satisfaction problem (CSP), where all constraint ... More Calabi-Yau algebrasDec 06 2006Jan 09 2007We introduce some new algebraic structures arising naturally in the geometry of Calabi-Yau manifolds and mirror symmetry. We give a universal construction of Calabi-Yau algebras in terms of a noncommutative symplectic DG algebra resolution. In dimension ... More A remark on a theorem of M. HaimanJul 04 2005We deduce a special case of a theorem of M. Haiman concerning alternating polynomials in 2n variables from our results about almost commuting variety, obtained earlier in a joint work with W.-L. Gan. Lectures on Noncommutative GeometryJun 29 2005These Lectures are based on a course on noncommutative geometry given by the author in 2003 at the University of Chicago. The lectures contain some standard material, such as Poisson and Gerstenhaber algebras, deformations, Hochschild cohomology, Serre ... More Perverse sheaves on a Loop group and Langlands' dualityNov 13 1995Nov 20 2000An intrinsic construction of the tensor category of finite dimensional representations of the Langlands dual group of G in terms of a tensor category of perverse sheaves on the loop group, LG, is given. The construction is applied to the study of the ... More Has the E791 experiment measured the pion wave function profile ?Mar 28 2001Jun 13 2001The cross section of hard diffractive dissociation of the pion into two jets is calculated. It is obtained that the distribution of longitudinal momenta for jets is not simply proportional to the profile of the pion wave function, but depends on it in ... More J/Psi theory review, or from J to PsiJun 16 1999Jul 16 19991) Hard exclusive processes in QCD: main characteristic properties; 2) Experimental and theoretical status of the J/Psi and Psi^\prime decays. Properties of the SU(N_c) Yang-Mills vacuum stateAug 16 1998Mar 18 1999The asymptotic behaviour of the vacuum energy density, ${\bar E}(\theta)$, at $\theta \ra \pm i \infty$ is found out. A new interpretation and a qualitative discussion of the ${\bar E}(\theta)$ behaviour are presented. It is emphasized that the vacuum ... More The Infrared Boundary of Perturbative QCDSep 14 2001Evidence is reviewed suggesting that QCD remains a perturbative theory with a (relatively) small coupling constant down to a distinct infrared boundary on perturbative physics, a boundary corresponding to the momentum scale associated with a beta-function ... More A rational construction of Lie algebras of type E_7Sep 27 2013Jul 03 2015We give an explicit construction of Lie algebras of type $E_7$ out of a Lie algebra of type $D_6$ with some restrictions. Up to odd degree extensions, every Lie algebra of type $E_7$ arises this way. For Lie algebras that admit a $56$-dimensional representation ... More Two-time free energy distribution function in the KPZ problemJul 22 2015The explicit expression for the two time free energy distribution function in one-dimensional random directed polymers is derived in terms of the Bethe ansatz replica technique. It is show that such type of the distribution function can be represented ... More 100 years of Weyl's lawAug 13 2016We discuss the asymptotics of the eigenvalue counting function for partial differential operators and related expressions paying the most attention to the sharp asymptotics. We consider Weyl asymptotics, asymptotics with Weyl principal parts and correction ... More Toric Landau-Ginzburg modelsSep 24 2018This is a review of the theory of toric Landau-Ginzburg models - the effective approach to mirror symmetry for Fano varieties. We mainly focus on the cases of dimensions 2 and 3, as well as on the case of complete intersections in weighted projective ... More Using boundaries to find smooth normsNov 06 2013Apr 28 2014The aim of this paper is to present a tool used to show that certain Banach spaces can be endowed with $C^k$ smooth equivalent norms. The hypothesis uses particular countable decompositions of certain subsets of $B_{X^*}$, namely boundaries. Of interest ... More Schroedinger Operator with Strong Magnetic Field near BoundaryMay 03 2010May 04 2010We consider 2-dimensional Schroedinger operator with the non-degenerating magnetic field in the domain with the boundary and under certain non-degeneracy assumptions we derive spectral asymptotics with the remainder estimate better than $O(h^{-1})$, up ... More