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Results for "Anastasia Antsiferova"

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Video Distortion Method for VMAF Quality Values IncreasingJul 10 2019Video quality measurement takes an important role in many applications. Full-reference quality metrics which are usually used in video codecs comparisons are expected to reflect any changes in videos. In this article, we consider different colour corrections ... More
Barriers towards no-reference metrics application to compressed video quality analysis: on the example of no-reference metric NIQEJul 08 2019This paper analyses the application of no-reference metric NIQE to the task of video-codec comparison. A number of issues in the metric behaviour on videos was detected and described. The metric has outlying scores on black and solid-coloured frames. ... More
Lax pair formulation in the simultaneous presence of boundaries and defectsApr 29 2014Jan 07 2015Inspired by recent results on the effect of integrable boundary conditions on the bulk behavior of an integrable system, and in particular on the behavior of an existing defect we systematically formulate the Lax pairs in the simultaneous presence of ... More
Type-I integrable quantum impurities in the Heisenberg modelJul 10 2013Nov 26 2013Type-I quantum impurities are investigated in the context of the integrable Heisenberg model. This type of defects is associated to the (q)-harmonic oscillator algebra. The transmission matrices associated to this particular type of defects are computed ... More
A note on the boundary spin $s$ XXZ chainDec 26 2006The open spin $s$ XXZ model with non-diagonal boundaries is considered. Within the algebraic Bethe ansatz framework and in the spirit of earlier works we derive suitable reference states. The derivation of the reference state is the crucial point in this ... More
Quantum spin chain with "soliton non-preserving" boundary conditionsJun 26 2000Jan 16 2001We consider the case of an integrable quantum spin chain with "soliton non-peserving" boundary conditions. This is the first time that such boundary conditions have been considered in the spin chain framework. We construct the transfer matrix of the model, ... More
Fused integrable lattice models with quantum impurities and open boundariesMar 24 2003Sep 09 2003The alternating integrable spin chain and the $RSOS(q_{1},q_{2};p)$ model in the presence of a quantum impurity are investigated. The boundary free energy due to the impurity is derived, the ratios of the corresponding $g$ functions at low and high temperature ... More
Near Anti-de Sitter Geometry and Corrections to the Large N Wilson LoopMar 26 1998Within recent Maldacena's proposal to relate gauge theories in the large N limit to the supergravity in the AdS background and recipe for calculation the Wilson loop, we compute corrections to the energy of quark/anti-quark pair in the large N limit.
Three-block p-branes in various dimensionsAug 15 1996Sep 19 1996It is shown that a Lagrangian, describing the interaction of the gravitation field with the dilaton and the antisymmetric tensor in arbitrary dimension spacetime, admits an isotropic p-brane solution consisting of three blocks. Relations with known p-brane ... More
Discreteness in deSitter Space and Quantization of Kahler ManifoldsJan 25 2001Jan 27 2001Recently, it has been proposed that the dimension of the Hilbert space of quantum gravity in deSitter space is finite and moreover it is expressed in terms of the coupling constants by using the entropy formula. A weaker conjecture would be that the coupling ... More
Solvable extensions of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^2$Mar 01 2018Jun 17 2019For a sequence of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^2$ introduced by Camacho, G\'{o}mez, Gonz\'{a}lez and Omirov, all possible right and left solvable indecomposable extensions over the field $\Bbb R$ are ... More
Asymptotic Stability of the optimal filter for non-ergodic signalsOct 02 2002Feb 21 2005In this paper, we study the problem of estimating a Markov chain $X$(signal) from its noisy partial information $Y$, when the transition probability kernel depends on some unknown parameters. Our goal is to compute the conditional distribution process ... More
A classical variant of the vertex algebra & the auxiliary linear problemJun 27 2015Jul 12 2015We propose a classical analogue of the vertex algebra in the context of classical integrable field theories. We use this fundamental notion to describe the auxiliary function of the linear auxiliary problem as a classical vertex operator. Then using the ... More
The open XXZ and associated models at q root of unityMar 14 2006Dec 11 2006The generalized open XXZ model at $q$ root of unity is considered. We review how associated models, such as the $q$ harmonic oscillator, and the lattice sine-Gordon and Liouville models are obtained. Explicit expressions of the local Hamiltonian of the ... More
Classical impurities associated to high rank algebrasDec 17 2013Apr 28 2014Classical integrable impurities associated to high rank (gl_N) algebras are investigated. A particular prototype i.e. the vector non-linear Schr\"{o}dinger (NLS) model is chosen as an example. A systematic construction of local integrals of motion as ... More
Defects in the discrete non-linear Schrodinger modelJun 08 2011Sep 05 2011The discrete non-linear Schrodinger (NLS) model in the presence of an integrable defect is examined. The problem is viewed from a purely algebraic point of view, starting from the fundamental algebraic relations that rule the model. The first charges ... More
On boundary super algebrasOct 07 2009Jul 08 2013We examine the symmetry breaking of super algebras due to the presence of appropriate integrable boundary conditions. We investigate the boundary breaking symmetry associated to both reflection algebras and twisted super Yangians. We extract the generators ... More
On Kazhdan's property (T) for isotropic reductive groupsFeb 09 2016We show that the standard set of elementary generators of an elementary isotropic reductive group over a connected finitely generated ring is a Kazhdan subset. This generalizes the corresponding result of M. Ershov, A. Jaikin-Zapirain, and M. Kassabov ... More
Domain Wall in MQCD and Supersymmetric Cycles in Exceptional Holonomy ManifoldsOct 15 1997Dec 16 1997It was conjectured by Witten that a BPS-saturated domain wall exists in the M-theory fivebrane version of QCD (MQCD) and can be represented as a supersymmetric three-cycle in the sense of Becker et al with an appropriate asymptotic behavior. We derive ... More
Solvable extensions of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^2$Mar 01 2018For a sequence of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^2$ introduced by Camacho, G\'{o}mez, Gonz\'{a}lez and Omirov, all possible right and left solvable indecomposable extensions over the field $\Bbb R$ are ... More
Solvable extensions of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^4$Mar 01 2018May 29 2019For a sequence of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^4$ introduced by Camacho, G\'{o}mez, Gonz\'{a}lez and Omirov, all possible right and left solvable indecomposable extensions over the field $\Bbb C$ are ... More
On Gevrey orders of power expansions of solutions to the third and fifth Painlevé equationsOct 20 2013The question under consideration is Gevrey summability of power expansions of solutions to the third and fifth Painlev\'{e} equations near infinity. Methods of French and Japaneese schools are used to analyse these properties of formal power-series solutions. ... More
Coarse-grained modeling of multiscale diffusions: the p-variation estimatesFeb 17 2010We study the problem of estimating parameters of the limiting equation of a multiscale diffusion in the case of averaging and homogenization, given data from the corresponding multiscale system. First, we review some recent results that make use of the ... More
Solvable extensions of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^4$May 26 2019For a sequence of the naturally graded quasi-filiform Leibniz algebra of second type $\mathcal{L}^4$ introduced by Camacho, G\'{o}mez, Gonz\'{a}lez and Omirov, all the possible right solvable indecomposable extensions over the field $\Bbb C$ are constructed. ... More
Transfers for non-stable K_1-functors of classical typeAug 22 2014Nov 28 2015Let k be a field. Let G be an absolutely almost simple simply connected k-group of type A_l, l>=2, or D_l, l>=4, containing a 2-dimensional split torus. If G is of type D_l, assume moreover that char k is different from 2. We show that the Nisnevich sheafification ... More
Selected Topics in Classical IntegrabilityOct 19 2011Feb 29 2012Basic notions regarding classical integrable systems are reviewed. An algebraic description of the classical integrable models together with the zero curvature condition description is presented. The classical r-matrix approach for discrete and continuum ... More
On reflection algebras and twisted YangiansMar 29 2004Apr 27 2005It is known that integrable models associated to rational $R$ matrices give rise to certain non-abelian symmetries known as Yangians. Analogously `boundary' symmetries arise when general but still integrable boundary conditions are implemented, as originally ... More
Jumps and twists in affine Toda field theoriesJul 29 2014Feb 02 2015The concept of point-like "jump" defects is investigated in the context of affine Toda field theories. The Hamiltonian formulation is employed for the analysis of the problem. The issue is also addressed when integrable boundary conditions ruled by the ... More
A note on gl_N type-I integrable defectsAug 08 2013Feb 02 2014Type-I quantum defects are considered in the context of the gl_N spin chain. The type-I defects are associated to the generalized harmonic oscillator algebra, and the chosen defect matrix is the one of the vector non-linear Schrodinger (NLS) model. The ... More
Generic boundary scattering in the open XXZ chainNov 05 2007Mar 31 2008The open critical XXZ spin chain with a general right boundary and a trivial diagonal left boundary is considered. Within this framework we propose a simple computation of the exact generic boundary S-matrix (with diagonal and non-diagonal entries), starting ... More
Fusion and Analytical Bethe Ansatz for the $A_{\n-1}^{(1)}$ Open Spin ChainJun 12 2000We generalise the fusion procedure for the $A_{\n-1}^{(1)}$ open spin chain ($\n>2$) and we show that the transfer matrix satisfies a crossing property. We use these results to solve the $A_{\n-1}^{(1)}$ open spin chain with $U_{q} (SU(\n))$ symmetry ... More
Domain Walls in MQCD and Monge-Ampere EquationJan 25 1998Mar 10 1998We study Witten's proposal that a domain wall exists in M-theory fivebrane version of QCD (MQCD) and that it can be represented as a supersymmetric three-cycle in G_2 holonomy manifold. It is shown that equations defining the U(1) invariant domain wall ... More
Rarita-Schwinger Field in the AdS/CFT CorrespondenceSep 01 1998A free Rarita-Schwinger field in the Anti-de Sitter space is considered. We show that the usual action can be supplemented by a boundary term that can be interpreted as the generating functional of the correlation functions in a conformal field theory ... More
The lower estimate for wandering rate of solution to a linear equation in terms of its frequencyDec 29 2012This research article compares two characteristics of solutions of linear differential equations of the third order with variable coefficients. It appears that there is a lower estimate for wandering rate of solution to a linear equation in terms of its ... More
Homotopy invariance of non-stable K_1-functorsNov 20 2011Feb 13 2013Let G be reductive algebraic group over a field k, such that every semisimple normal subgroup of G has isotropic rank >=2. Let K_1^G be the non-stable K_1-functor associated to G (also called the Whitehead group of G in the field case). We show that K_1^G(k)=K_1^G(k[X_1,...,X_n]) ... More
The XXX spin s quantum chain and the alternating $s^{1}$, $s^{2}$ chain with boundariesJan 02 2002Apr 18 2002The integrable XXX spin s quantum chain and the alternating $s^{1}$, $s^{2}$ ($s^{1}-s^{2}={1\over 2}$) chain with boundaries are considered. The scattering of their excitations with the boundaries via the Bethe ansatz method is studied, and the exact ... More
"New" boundary conditions in integrable lattice modelsApr 09 2001We consider the case of an integrable quantum spin chain with ``soliton non-preserving'' boundary conditions. This is the first time that such boundary conditions have been considered in the spin chain framework. We construct the transfer matrix of the ... More
Classical integrable defects as quasi Bäcklund transformationsMar 15 2016Aug 12 2016We consider the algebraic setting of classical defects in discrete and continuous integrable theories. We derive the "equations of motion" on the defect point via the space-like and time-like description. We then exploit the structural similarity of these ... More
Asymmetric Twin Representation: the Transfer Matrix SymmetryJun 19 2006Jan 10 2007The symmetry of the Hamiltonian describing the asymmetric twin model was partially studied in earlier works, and our aim here is to generalize these results for the open transfer matrix. In this spirit we first prove, that the so called boundary quantum ... More
On the symmetries of integrable systems with boundariesSep 21 2005We employ appropriate realizations of the affine Hecke algebra and we recover previously known non-diagonal solutions of the reflection equation for the $U_{q}(\hat{gl_n})$ case. With the help of linear intertwining relations involving the aforementioned ... More
Boundary non-local charges from the open spin chainFeb 24 2004Dec 16 2005The $N$ site open XXZ quantum spin chain with a right non-diagonal boundary and special diagonal left boundary is considered. The boundary non-local charges originally obtained from a field theoretical viewpoint, for the sine Gordon model on the half ... More
From affine Hecke algebras to boundary symmetriesSep 22 2004Dec 16 2005Motivated by earlier works we employ appropriate realizations of the affine Hecke algebra and we recover previously known non-diagonal solutions of the reflection equation for the $U_{q}(\hat{gl_n})$ case. The corresponding $N$ site spin chain with open ... More
Transmission matrices in gl(N) & U_q(gl(N)) quantum spin chainsApr 22 2013Aug 22 2013The gl(N) and U_q(gl(N)) quantum spin chains in the presence of integrable spin impurities are considered. Within the Bethe ansatz formulation, we derive the associated transmission amplitudes, and the corresponding transmission matrices -representations ... More
Murphy elements from the double-row transfer matrixDec 04 2008Mar 10 2009We consider the double-row (open) transfer matrix constructed from generic tensor-type representations of various types of Hecke algebras. For different choices of boundary conditions for the relevant integrable lattice model we express the double-row ... More
$A_n^{(1)}$ affine Toda field theories with integrable boundary conditions revisitedMar 06 2008Sep 17 2008Generic classically integrable boundary conditions for the $A_{n}^{(1)}$ affine Toda field theories (ATFT) are investigated. The present analysis rests primarily on the underlying algebra, defined by the classical version of the reflection equation. We ... More
Non-diagonal reflection for the non-critical XXZ modelDec 18 2007The most general physical boundary $S$-matrix for the open XXZ spin chain in the non-critical regime ($\cosh (\eta)>1$) is derived starting from the bare Bethe ansazt equations. The boundary $S$-matrix as expected is expressed in terms of $\Gamma_q$-functions. ... More
Thermodynamics of the critical $RSOS(q_{1}, q_{2} ;q)$ modelJun 16 2002Nov 29 2002The thermodynamic Bethe ansatz method is employed for the study of the integrable critical $RSOS(q_{1}, q_{2};q)$ model. The high and low temperature behavior are investigated, and the central charge of the effective conformal field theory is derived. ... More
Adaptive Mirror Descent for Constrained OptimizationMay 04 2017This paper seeks to address how to solve non-smooth convex and strongly convex optimization problems with functional constraints. The introduced Mirror Descent (MD) method with adaptive stepsizes is shown to have a better convergence rate than MD with ... More
Adaptive Stochastic Mirror Descent for Constrained OptimizationMay 04 2017Mirror Descent (MD) is a well-known method of solving non-smooth convex optimization problems. This paper analyzes the stochastic variant of MD with adaptive stepsizes. Its convergence on average is shown to be faster than with the fixed stepsizes and ... More
A variational approximation scheme for elastodynamic problems using a new class of admissible mappingsAug 02 2018We consider a variational approximation scheme for the 3D elastodynamics problem. Our approach uses a new class of admissible mappings that are closed with respect to the space of mappings with finite distortion.
Isotropic reductive groups over discrete Hodge algebrasDec 13 2017Aug 01 2018Let G be a reductive group over a commutative ring R. We say that G has isotropic rank >=n, if every normal semisimple reductive R-subgroup of G contains (G_m)^n. We prove that if G has isotropic rank >=1 and R is a regular domain containing an infinite ... More
Weyl Equation and (Non)-Commutative SU(n+1) BPS MonopolesMay 28 2010Aug 13 2010We apply the ADHMN construction to obtain the SU(n+1)(for generic values of n) spherically symmetric BPS monopoles with minimal symmetry breaking. In particular, the problem simplifies by solving the Weyl equation, leading to a set of coupled equations, ... More
Boundary Lax pairs from non-ultra local Poisson algebrasMay 26 2009Jun 11 2009We consider non-ultra local linear Poisson algebras on a continuous line . Suitable combinations of representations of these algebras yield representations of novel generalized linear Poisson algebras or "boundary" extensions. They are parametrized by ... More
The sine-Gordon model in the presence of defectsFeb 11 2013The sine-Gordon model in the presence of dynamical integrable defects is investigated. This is an application of the algebraic formulation introduced for integrable defects in earlier works. The quantities in involution as well as the associated Lax pairs ... More
Sigma models in the presence of dynamical point-like defectsJul 23 2012Nov 04 2012Point-like Liouville integrable dynamical defects are introduced in the context of the Landau-Lifshitz and Principal Chiral (Faddeev-Reshetikhin) models. Based primarily on the underlying quadratic algebra we identify the first local integrals of motion, ... More
Liouville integrable defects: the non-linear Schrodinger paradigmOct 21 2011Feb 14 2012A systematic approach to Liouville integrable defects is proposed, based on an underlying Poisson algebraic structure. The non-linear Schrodinger model in the presence of a single particle-like defect is investigated through this algebraic approach. Local ... More
Light-Cone String Field Theory in a Plane Wave BackgroundOct 03 2003These lecture notes present an elementary introduction to light-cone string field theory, with an emphasis on its application to the study of string interactions in the plane wave limit of AdS/CFT. We summarize recent results and conclude with a list ... More
Vacuum States and the S-Matrix in dS/CFTDec 22 2001Feb 14 2002We propose a definition of dS/CFT correlation functions by equating them to S-matrix elements for scattering particles from I^- to I^+. In planar coordinates, which cover half of de Sitter space, we consider instead the S-vector obtained by specifying ... More
Noncommutative solitons on Kahler manifoldsJun 20 2001Jun 28 2002We construct a new class of scalar noncommutative multi-solitons on an arbitrary Kahler manifold by using Berezin's geometric approach to quantization and its generalization to deformation quantization. We analyze the stability condition which arises ... More
From Twistor String Theory To Recursion RelationsSep 01 2009Witten's twistor string theory gives rise to an enigmatic formula [arXiv:hep-th/0403190] known as the "connected prescription" for tree-level Yang-Mills scattering amplitudes. We derive a link representation for the connected prescription by Fourier transforming ... More
From Poland to "Petersburg": The Banach-Tarski Paradox in Bely's Modernist NovelOct 16 2017Andrei Bely's novel "Petersburg," first published in 1913, was declared by Vladimir Nabokov one of the four greatest masterpieces of 20th-century prose. The Banach-Tarski Paradox, published in 1924, is one of the most striking and well-known results in ... More
Invariant spanning trees for quadratic rational mapsAug 16 2018Jan 12 2019We study Thurston equivalence classes of quadratic post-critically finite branched coverings. For these maps, we introduce and study invariant spanning trees. We give a computational procedure for searching for invariant spanning trees. This procedure ... More
How to Build Your Network? A Structural AnalysisMay 12 2016Creating new ties in a social network facilitates knowledge exchange and affects positional advantage. In this paper, we study the process, which we call network building, of establishing ties between two existing social networks in order to reach certain ... More
Viterbo's conjecture for certain Hamiltonians of classical mechanicsDec 07 2018We study some particular cases of Viterbo's conjecture relating volumes of convex bodies and actions of closed characteristics on their boundaries, focusing on the case of a Hamiltonian of classical mechanical type, splitting into summands depending on ... More
Gromov Conjecture on Surface Subgroups: Computational ExperimentsJan 09 2010In this paper we investigate Gromov's question: whether every one-ended word hyperbolic group contains a surface subgroup. The case of double groups is considered by studying the associated one relator groups. We show that the majority (96%) of the randomly ... More
First solar butterfly diagram from Schwabe's observations in 1825-1867Oct 15 2010The original sunspot observations by Heinrich Samuel Schwabe of 1825-1867 were digitized and a first subset of spots was measured. In this initial project, we determined more than 14 000 sunspot positions and areas comprising about 11% of the total amount ... More
Principal chiral model scattering and the alternating quantum spin chainMay 03 2001Jun 14 2001We consider the critical alternating quantum spin chain with ${q_{+}\over 2}$, ${q_{-} \over2}$ spins. Using the Bethe ansatz technique we find explicit expressions for the $S$-matrix of the model. We show that in the limit that $q_{\pm} \rightarrow \infty$ ... More
Systematic derivation of boundary Lax pairsDec 10 2007Dec 14 2007We systematically derive the Lax pair formulation for both discrete and continuum integrable classical theories with consistent boundary conditions.
Principal bundles of reductive groups over affine schemesApr 08 2012Mar 16 2013Let R be a semi-local regular domain containing an infinite perfect field k, and let K be the field of fractions of R. Let G be a reductive semi-simple simply connected R-group scheme such that each of its R-indecomposable factors is isotropic. We prove ... More
Towards an optimal algorithm for recognizing Laman graphsJan 15 2008Laman graphs are fundamental to rigidity theory. A graph G with n vertices and m edges is a generic minimally rigid graph (Laman graph), if m=2n-3 and every induced subset of k vertices spans at most 2k-3 edges. We consider the verification problem: Given ... More
Superstring Interactions in a pp-wave Background IIJun 10 2002Oct 10 2002In type IIB light-cone superstring field theory, the cubic interaction has two pieces: a delta-functional overlap and an operator inserted at the interaction point. In this paper we extend our earlier work hep-th/0204146 by computing the matrix elements ... More
Superstring Interactions in a pp-wave BackgroundApr 17 2002Nov 09 2002We construct light-cone gauge superstring field theory in a pp-wave background with Ramond-Ramond flux. The leading term in the interaction Hamiltonian is determined up to an overall function of $p^+$ by requiring closure of the pp-wave superalgebra. ... More
Yang-Mills Correlation Functions from Integrable Spin ChainsJul 16 2004The relation between the dilatation operator of N=4 Yang-Mills theory and integrable spin chains makes it possible to compute the one-loop anomalous dimensions of all operators in the theory. In this paper we show how to apply the technology of integrable ... More
A Fast Radio Burst Occurs Every Second throughout the Observable UniverseJun 20 2017Aug 29 2017Recent multi-telescope observations of the repeating Fast Radio Burst FRB 121102 reveal a Gaussian-like spectral profile and associate the event with a dwarf metal-poor galaxy at a cosmological redshift of 0.19. Assuming that this event represents the ... More
Correlation Functions in Non-Relativistic HolographyMar 13 2009Mar 15 2009Recently constructed gravity solutions with Schrodinger symmetry provide a new example of AdS/CFT-type dualities for the type of non-relativistic field theories relevant to certain cold atom systems. In this paper we use the gravity side to calculate ... More
Human Associations Help to Detect Conventionalized Multiword ExpressionsSep 12 2017In this paper we show that if we want to obtain human evidence about conventionalization of some phrases, we should ask native speakers about associations they have to a given phrase and its component words. We have shown that if component words of a ... More
On effects of stochastic regularization for the pressureless gas dynamicsOct 01 2010We extend our result of [1] and show that one can associate with the stochastically perturbed non-viscid Burgers equation a system of viscous balance laws. The Cauchy data for the Burgers equation generates the data for this system. Till the moment of ... More
The Dehn-Sommerville Relations and the Catalan MatroidDec 14 2015The $f$-vector of a $d$-dimensional polytope $P$ stores the number of faces of each dimension. When $P$ is simplicial the Dehn--Sommerville relations condense the $f$-vector into the $g$-vector, which has length $\lceil{\frac{d+1}{2}}\rceil$. Thus, to ... More
A Survey of Representation Stability TheoryMar 04 2016In this survey article we summarize the current state of research in representation stability theory. We look at three different, yet related, approaches, using (1) the category of FI-modules, (2) Schur-Weyl duality, and (3) finitely-generated modules ... More
Solutions of the Generic Non-Compact Weyl EquationJan 30 2012Apr 27 2012In this paper, solutions of the generic non-compact Weyl equation are obtained. In particular, by identifying a suitable similarity transformation and introducing a non-trivial change of variables we are able to implement azimuthal dependence on the solutions ... More
The Non-Compact Weyl EquationDec 27 2010Apr 07 2011A non-compact version of the Weyl equation is proposed, based on the infinite dimensional spin zero representation of the sl_2 algebra. Solutions of the aforementioned equation are obtained in terms of the Kummer functions. In this context, we discuss ... More
Contractions of quantum algebraic structuresFeb 19 2010A general framework for obtaining certain types of contracted and centrally extended algebras is presented. The whole process relies on the existence of quadratic algebras, which appear in the context of boundary integrable models.
Dressing the Giant MagnonJul 03 2006Mar 21 2007We apply the dressing method to construct new classical string solutions describing various scattering and bound states of magnons. These solutions carry one, two or three SO(6) charges and correspond to multi-soliton configurations in the generalized ... More
All Googly Amplitudes from the B-model in Twistor SpaceFeb 16 2004It has recently been proposed that the D-instanton expansion of the open topological B-model on P^{3|4} is equivalent to the perturbative expansion of N=4 super Yang-Mills theory in four dimensions. In this note we extend the results of hep-th/0402016 ... More
Note on Plane Wave Quantum MechanicsMar 25 2003Apr 30 2003We study the quantum mechanics of BMN operators with two scalar impurities and arbitrarily many traces, at one loop and all genus. We prove an operator identity which partially elucidates the structure of this quantum mechanics, provides some support ... More
A Pendant for Polya: The One-Loop Partition Function of N=4 SYM on R x S^3Aug 23 2004Sep 20 2004We study weakly coupled SU(N) N = 4 super Yang-Mills theory on R x S^3 at infinite N, which has interesting thermodynamics, including a Hagedorn transition, even at zero Yang-Mills coupling. We calculate the exact one-loop partition function below the ... More
Thermodynamics and conformal properties of XXZ chains with alternating spinsDec 01 2003The quantum periodic XXZ chain with alternating spins is studied. The properties of the related R-matrix and Hamiltonians are discussed. A compact expression for the ground state energy is obtained. The corresponding conformal anomaly is found via the ... More
Signature of Excess Radio Background in the 21-cm Global Signal and Power SpectrumFeb 07 2019The recent tentative detection by the EDGES Low-Band antenna of the hydrogen 21-cm line from cosmic dawn, if confirmed, is the first ever signature observed from the epoch of primordial star formation. However, the magnitude and the shape of this signal ... More
The 21-cm Signal from the Cosmological Epoch of RecombinationNov 18 2013Nov 28 2013The redshifted 21-cm emission by neutral hydrogen offers a unique tool for mapping structure formation in the early universe in three dimensions. Here we provide the first detailed calculation of the 21-cm emission signal during and after the epoch of ... More
Jetted Tidal Disruptions of Stars as a Flag of Intermediate Mass Black Holes at High RedshiftsNov 02 2016Tidal disruption events (TDEs) of stars by single or binary supermassive black holes (SMBHs) brighten galactic nuclei and reveal a population of otherwise dormant black holes. Adopting event rates from the literature, we aim to establish general trends ... More
Utility maximisation and utility indifference price for exponential semi-martingale models with random factorMar 05 2013We consider utility maximization problem for semi-martingale models depending on a random factor $\xi$. We reduce initial maximization problem to the conditional one, given $\xi=u$, which we solve using dual approach. For HARA utilities we consider information ... More
A Distributed Procedure for Computing Stochastic Expansions with MathematicaSep 28 2010The solution of a (stochastic) differential equation can be locally approximated by a (stochastic) expansion. If the vector field of the differential equation is a polynomial, the corresponding expansion is a linear combination of iterated integrals of ... More
On Divergence of Puiseux Series Asymptotic Expansions of Solutions to the Third Painlevé EquationFeb 19 2017Feb 21 2017In this paper we present a family of values of the parameters of the third Painlev\'{e} equation such that Puiseux series formally satisfying this equation -- considered as series of $z^{2/3}$ -- are series of exact Gevrey order one. We prove the divergence ... More
Representations of finite-dimensional quotient algebras of the 3-string braid groupAug 20 2018Jan 22 2019We consider quotients of the group algebra of the $3$-string braid group $B_3$ by $p$-th order generic polynomial relations on the elementary braids. In cases $p=2,3,4,5$ these quotient algebras are finite dimensional. We give semisimplicity criteria ... More
Normal structure of isotropic reductive groups over ringsJan 26 2018The paper studies the lattice of subgroups of an isotropic reductive group G(R) over a commutative ring R, normalized by the elementary subgroup E(R). We prove the sandwich classification theorem for this lattice under the assumptions that the reductive ... More
A cactus theorem for end cutsOct 23 2011Dinits-Karzanov-Lomonosov showed that it is possible to encode all minimal edge cuts of a graph by a tree-like structure called a cactus. We show here that minimal edge cuts separating ends of the graph rather than vertices can be `encoded' also by a ... More
Elementary subgroup of an isotropic reductive group is perfectJan 07 2010Let G be an isotropic reductive algebraic group over a commutative ring R. Assume that the elementary subgroup E(R) of group of points G(R) is correctly defined. Then E(R) is perfect, except for the well-known cases of a split reductive group of type ... More
Diffusion Parameter Estimation for the Homogenized EquationJul 02 2018We construct a novel estimator for the diffusion coefficient of the limiting homogenized equation, when observing the slow dynamics of a multiscale model, in the case when the slow dynamics are of bounded variation. Previous research suggests subsampling ... More
Throughput-Distortion Computation Of Generic Matrix Multiplication: Toward A Computation Channel For Digital Signal Processing SystemsOct 26 2011The generic matrix multiply (GEMM) function is the core element of high-performance linear algebra libraries used in many computationally-demanding digital signal processing (DSP) systems. We propose an acceleration technique for GEMM based on dynamically ... More
The sine-Gordon model with integrable defects revisitedMay 08 2012Nov 02 2012Application of our algebraic approach to Liouville integrable defects is proposed for the sine-Gordon model. Integrability of the model is ensured by the underlying classical r-matrix algebra. The first local integrals of motion are identified together ... More