Results for "A. Sahami"

total 233969took 0.11s
A note on essentially left $φ$-contractible Banach algebrasJul 11 2019In this note, we show that \cite[Corollary 3.2]{sad} is not always true. In fact, we characterize essential left $\phi$-contractibility of the the group algebras in the term of compactness of its related locally compact group. Also we show that for any ... More
On homological notions of Banach algebras related to a characterJan 11 2014Sep 08 2018In this paper, we countinue our work in \cite{11}. We show that $L^{1}(G,w)$ is $\phi_{0}$-biprojective if and only if $G$ is compact, where $\phi_{0}$ is the augmentation character. We introduce the notions of character Johnson amenability and character ... More
On left $φ$-biprojectivity and left $φ$-biflatness of certain Banach algebrasMay 14 2019In this paper, we study left $\phi$-biflatness and left $\phi$-biprojectivity of some Banach algebras, where $\phi$ is a non-zero multiplicative linear function. We show that if the Banach algebra $A^{**}$ is left $\phi$-biprojective, then $A$ is left ... More
Approximate biprojectivity of certain semigroup algebrasSep 26 2014In this paper, we investigate the notion of approximate biprojectivity for semigroup algebras and for some Banach algebras related to semigroup algebras. We show that $\ell^{1}(S)$ is approximately biprojective if and only if $\ell^{1}(S)$ is biprojective, ... More
Approximate biprojectivity and $φ$-biflatness of certain Banach algebrasSep 26 2014Feb 04 2015In this paper we are going to investigate the approximate biprojectivity and the $\phi$-biflatness of some Banach algebras related to the locally compact groups. We show that a Segal algebra $S(G)$ is approximate biprojective if and only if $G$ is compact. ... More
Phi-Homological Properties of Beurling AlgebrasJan 11 2014In this paper, we investigate $\phi$-homological properties for Beurling algebras, where $\phi$ is a character on those Banach algebras. We show that $L^{1}(G,w)$ is $\phi_{0}$-biprojective if and only if $G$ is compact, where $\phi_{0}$ is the augmentation ... More
On the existence of an ultra central approximate identity for certain semigroup algebrasJan 05 2018In this paper we characterize the existance of an ultra central approximate identity for $\ell^{1}(S)$, where $S$ is a uniformly locally finite inverse semigroup. As an application, for the Brandt semigroup $S=M^{0}(G,I)$ over a non-empty set $I$, we ... More
Johnson pseudo-contractibility and pseudo-amenability of $ θ$-Lau product of Banach algebrasJan 07 2018Given Banach algebras $ A $ and $ B $ with $ \theta\in\Delta(B) $. We shall study the Johnson pseudo-contractibility and pseudo-amenability of $ \theta $-Lau product $ A\times_{\theta} B $. We show that if $ A\times_{\theta} B $ is Johnson pseudo-contractible, ... More
Johnson pseudo-contractibility of certain Banach algebras and their nilpotent idealsDec 14 2017Sep 21 2018In this paper, we study the notion of Johnson pseudo-contractibility for certain Banach algebras. For a bicyclic semigroup $S$, we show that $\ell^{1}(S)$ is not Johnson pseudo-contractible. Also for a Johnson pseudo-contractible Banach algebra $A$, we ... More
On approximate Connes-biprojectivity of dual Banach algebrasMay 09 2018Nov 17 2018In this paper, we introduce a notion of approximate Connes-biprojectivity for dual Banach algebras. We study the relation between approximate Connes-biprojectivity, Johnson pseudo-Connes amenability and $\varphi$-Connes amenability. We propose a criterion ... More
On Connes amenability of upper triangular matrix algebrasJan 10 2018Apr 20 2018In this paper, we study the notion of Connes amenability for a class of $I\times{I}$-upper triangular matrix algebra $UP(I,\mathcal{A})$, where $\mathcal{A}$ is a dual Banach algebra with a non-zero $wk^\ast$-continuous character and $I$ is a totally ... More
$WAP$-biprojectivity of the enveloping dual Banach algebrasJan 10 2018Dec 01 2018In this paper, we introduce a new notion of biprojectivity, called $WAP$-biprojectivity for $F(\mathcal{A})$, the enveloping dual Banach algebra associated to a Banach algebra $\mathcal{A}$. We find some relations between Connes biprojectivity, Connes ... More
Strong pseudo-Connes amenability of dual Banach algebrasJul 30 2018In this paper, we introduce the new notion of strong pseudo-Connes amenability for dual Banach algebras. We study the relation between this new notion to the various notions of Connes amenability. Also we show that for every non-empty set $I$, $M_I(\mathbb{C})$ ... More
Johnson pseudo-Connes amenability of dual Banach algebrasJan 10 2018Apr 18 2018We introduce the notion of Johnson pseudo-Connes amenability for dual Banach algebras. We study the relation between this new notion with the various notions of Connes amenability like Connes amenability, approximate Connes amenability and pseudo Connes ... More
A note on left $φ$-biflat Banach algebrasMay 14 2019In this paper, we study the notion of $\phi$-biflatness for some Banach algebras, where $\phi$ is a non-zero multiplicative linear functional. We show that the Segal algebra $S(G)$ is left $\phi$-biflat if and only if $G$ is amenable. Also, we characterize ... More
Generalized notion of amenability for a class of matrix algebrasJun 27 2016We investigate the notions of amenability and its related homological notions for a class of I ?I-upper triangular matrix algebra, say UP(I;A), where A is a Banach algebra equipped with a non- zero character. We show that UP(I;A) is pseudo-contractible ... More
Position Sensor-less and Adaptive Speed Design for Controlling Brush-less DC Motor DrivesAug 21 2018This paper proposes a method for direct torque control of Brushless DC (BLDC) motors. Evaluating the trapezium of back-EMF is needed, and is done via a sliding mode observer employing just one measurement of stator current. The effect of the proposed ... More
On (approximate) homological notions of certain Banach algebrasJun 05 2018In this paper, we study the notion of $\phi$-biflatness, $\phi$-biprojectivity, approximate biprojectivity and Johnson pseudo-contractibility for a new class of Banach algebras. Using this class of Banach algebras we give some examples which are approximately ... More
A note on approximately biflat banach algebrasJun 27 2016In this paper, we study the notion of approximately bi at Banach algebras for second dual Banach algebras and semigroup algebras. We show that for a locally compact group G, if S(G)?? is approximately bi at, then G is amenable group. Also we give some ... More
Generalized notion of amenability for a class of matrix algebrasJun 27 2016Feb 08 2017We investigate the notions of amenability and its related homological notions for a class of $I\times I$-upper triangular matrix algebra, say $UP(I,A)$, where $A$ is a Banach algebra equipped with a non-zero character. We show that $UP(I,A)$ is pseudo-contractible ... More
Approximate biflatness and Johnson pseudo-contractibility of some Banach algebrasJun 11 2018Aug 30 2018In this paper, we study the structure of Lipschitz algebras under the notions of approximate biflatness and Johnson pseudo-contractibility. We show that for a compact metric space $X,$ the Lipschitz algebras $Lip_{\alpha}(X)$ and $\ell ip_{\alpha}(X)$ ... More
Left $φ$-biprojectivity of some Banach algebrasMay 14 2019In this paper, we introduce a homological notion of left $\phi$-biprojectivity for Banach algebras, where $\phi$ is a non-zero multiplicative linear functional. We show that for a locally compact group $G$, the Segal algebra $S(G)$ is left $\phi$-contractible ... More
Strong pseudo-amenability of some Banach algebrasFeb 06 2018In this paper we introduce a new notion of strong pseudo-amenability for Banach algebras. We study strong pseudo-amenability of some Matrix algebras. Using this tool, we characterize strong pseudo-amenability of $\ell^{1}(S)$, provided that $S$ is a uniformly ... More
On approximately left phi-biprojective Banach algebrasJun 27 2016Aug 26 2016In this paper, for a Banach algebra A, we introduced the new notions of approximately left $\phi$-biprojective and approximately left character biprojective, where $\phi$ is a non-zero multiplicative linear functional on A. We show that for SIN group ... More
Making a Dynamic Interaction Between Two Power System Analysis SoftwareAug 21 2018This paper presents a distributed simulation based method for harmonic resonance assessment (HRA) in multi-area large-scale power systems. Further consideration is devoted to the early harmonic frequency-scan formulation to shape them into a Bordered ... More
Geodesic equations in the static and rotating dilaton black holes: Analytical solutions and applicationsJan 13 2016Jul 20 2016In this paper, we consider the timelike and null geodesics around the static [GMGHS (Gibbons, Maeda, Garfinkle, Horowitz and Strominger), magnetically charged GMGHS, electrically charged GMGHS] and the rotating (Kerr-Sen dilaton-axion) dilaton black holes. ... More
Limited individual attention and online virality of low-quality informationJan 10 2017Jan 10 2019Social media are massive marketplaces where ideas and news compete for our attention. Previous studies have shown that quality is not a necessary condition for online virality and that knowledge about peer choices can distort the relationship between ... More
Learning Program Embeddings to Propagate Feedback on Student CodeMay 22 2015Providing feedback, both assessing final work and giving hints to stuck students, is difficult for open-ended assignments in massive online classes which can range from thousands to millions of students. We introduce a neural network method to encode ... More
Deep Knowledge TracingJun 19 2015Knowledge tracing---where a machine models the knowledge of a student as they interact with coursework---is a well established problem in computer supported education. Though effectively modeling student knowledge would have high educational impact, the ... More
A study of RXTE and BeppoSAX observations of Cyg X-3Jan 14 2004We present an analysis of Cyg X-3 data from RXTE/PCA,HEXTE and ASM, supplemented by a selected spectrum from BeppoSAX. We fit the PCA/HEXTE spectra from 1996-2000 by a model including hybrid Comptonization, reflection and absorption, and classify them ... More
Non-reciprocal quantum interactions and devices via autonomous feed-forwardOct 20 2016In a recent work [A. Metelmann and A. A. Clerk, Phys. Rev. X 5, 021025 (2015)], a general reservoir-engineering approach for generating non-reciprocal quantum interactions and devices was described. We show here how in many cases this general recipe can ... More
Deciphering the minimum of energy of some walking technicolor modelsMay 11 2010There are quasi-conformal theories, like the Minimal and Ultraminimal Technicolor models, which may break dynamically the gauge symmetry of the Standard Model and at the same time are compatible with electroweak precision data. The main characteristic ... More
Strength of the Trilinear Higgs Boson Coupling in Technicolor ModelsOct 14 2005Oct 20 2005We discuss the strength of the trilinear Higgs boson coupling in technicolor (or composite) models in a model independent way. The coupling is determined as a function of a very general ansatz for the technicolor self-energy, and turns out to be equal ... More
Scalar bosons in Minimal and Ultraminimal Technicolor: Masses, trilinear couplings and widthsDec 05 2009May 04 2010We compute masses, trilinear self-couplings and decay widths into weak bosons of the scalar composite bosons in the case of the Minimal and Ultraminimal technicolor models. The masses, computed via the Bethe-Salpeter equation, turn out to be light and ... More
Graph homology: Koszul and Verdier dualityFeb 12 2007We show that Verdier duality for certain sheaves on the moduli spaces of graphs associated to Koszul operads corresponds to Koszul duality of operads. This in particular gives a conceptual explanation of the appearance of graph cohomology of both the ... More
Effects of the stellar wind on X-ray spectra of Cygnus X-3Oct 30 2007Feb 04 2008We study X-ray spectra of Cyg X-3 from BeppoSAX, taking into account absorption and emission in the strong stellar wind of its companion. We find the intrinsic X-ray spectra are well modelled by disc blackbody emission, its upscattering by hot electrons ... More
On open superstring partition function in inhomogeneous rolling tachyon backgroundOct 27 2003Jan 27 2004We consider open superstring partition function Z on the disc in time-dependent tachyon background T= f(x_i) e^{m x_0} where the profile function f depends on spatial coordinates. We compute Z to second order in derivatives of f and compare the result ... More
On gravitational couplings in D-brane actionNov 12 2002Oct 26 2004We compute the two closed string graviton - two open string scalar scattering amplitude on the disc to show that there is no second-derivative curvature - scalar coupling term R X^2 in the low-energy effective action of a D-brane in curved space in type ... More
Coherent effects in double-barrier Josephson junctionsDec 07 1999The general solution for ballistic electronic transport through double-barrier Josephson junctions is derived. We show the existence of a regime of phase-coherent transport in which the supercurrent is proportional to the single barrier transparency and ... More
The origin of the first and third generation fermion masses in a technicolor scenarioFeb 19 2003Jan 22 2004We argue that the masses of the first and third fermionic generations, which are respectively of the order of a few MeV up to a hundred GeV, are originated in a dynamical symmetry breaking mechanism leading to masses of the order $\alpha \mu$, where $\alpha$ ... More
On (non)integrability of classical strings in p-brane backgroundsNov 15 2012Jan 07 2013We investigate the question of possible integrability of classical string motion in curved p-brane backgrounds. For example, the D3-brane metric interpolates between the flat and the AdS_5 x S^5 regions in which string propagation is integrable. We find ... More
On the power of non-local boxesApr 18 2005Nov 07 2005A non-local box is a virtual device that has the following property: given that Alice inputs a bit at her end of the device and that Bob does likewise, it produces two bits, one at Alice's end and one at Bob's end, such that the XOR of the outputs is ... More
Casimir effect for scalar fields under Robin boundary conditions on platesJul 31 2000Oct 22 2001We study the Casimir effect for scalar fields with general curvature coupling subject to mixed boundary conditions $(1+\beta_{m}n^{\mu}\partial_{\mu})\phi =0$ at $x=a_{m}$ on one ($m=1$) and two ($m=1,2$) parallel plates at a distance $a\equiv a_{2}-a_{1}$ ... More
Technicolor models with coupled systems of Schwinger-Dyson equationsFeb 28 2019When Technicolor (TC), QCD, Extended Technicolor (ETC) and other interactions become coupled through their different Schwinger-Dyson equations, the solution of these equations are modified in comparison with the ones of the isolated equations. The change ... More
A statistical model of three-dimensional anisotropy and intermittency in strong Alfvénic turbulenceMay 24 2016Dec 14 2016We propose a simple statistical model of three-dimensionally anisotropic, intermittent, strong Alfv\'enic turbulence, incorporating both critical balance and dynamic alignment. Our model is based on log-Poisson statistics for Elsasser-field increments ... More
Evolution of atmospheric escape in close-in giant planets and their associated Ly$α$ and H$α$ transit predictionsAug 09 2019Strong atmospheric escape has been detected in several close-in exoplanets. As these planets are mostly made of hydrogen, observations in hydrogen lines, such as Ly-alpha and H-alpha lines, are powerful diagnostics of escape. Here, we simulate the evolution ... More
Topological response in Weyl semimetals and the chiral anomalyJun 08 2012Sep 25 2012We demonstrate that topological transport phenomena, characteristic of Weyl semimetals, namely the semi-quantized anomalous Hall effect and the chiral magnetic effect (equilibrium magnetic-field-driven current), may be thought of as two distinct manifestations ... More
Top quark threshold production in $γγ$ collision in the next-to-leading orderOct 27 1998Apr 23 1999The total cross section of the top quark-antiquark pair production near threshold in $\gamma\gamma$ collision is computed analytically up to the next-to-leading order in perturbative and nonrelativistic expansion for general photon helicity. The approximation ... More
On a subtle point of sum rules calculations: toy modelMar 30 1995We consider a two-point correlator in massless $\phi^3$ model within the ladder approximation . The spectral density of the correlator is known explicitly and does not contain any resonances. Meanwhile making use of the standard sum rules technique with ... More
Exact string background from a WZW model based on the Heisenberg groupMar 07 1994A WZW model for the non-semi-simple D-dimensional Heisenberg group, which directly generalizes the E_{2}^{c} group, is constructed. It is found to correspond to an D-dimensional string background of plane-wave type with physical Lorentz signature D-2. ... More
Notes on non-thermal X-ray radiation of radio supernova remnant W50 and collimated radiation of SS433Jun 19 2013Diffuse X-ray emission of the radio nebula W50 along the line of the of jets of the microquasar SS433 has a non-thermal power law component. This could be the inverse-Compton scattered emission of the SS433 accretion disk funnel, which is collimated in ... More
Next-to-next-to-leading order vacuum polarization function of heavy quark near threshold and sum rules for $b \bar b$ systemMar 16 1998Apr 06 1998A correlator of the vector current of a heavy quark is computed analytically near threshold in the next-to-next-to-leading order in perturbative and relativistic expansion that includes $\al_s^2$, $\al_sv$ and $v^2$ corrections in the coupling constant ... More
Comment on ``Next-to-next-to-leading order vacuum polarization function of heavy quark near threshold and sum rules for $b \bar b$ system'' and ``Next-to-next-to-leading order relation between $R(e^+e^-\to b\bar b)$ and $Γ_{\rm sl}(b\to clν_l)$ and precise ... MoreJan 19 1999The most recent recalculation of the two-loop correction to the static quark-antiquark potential gave the numerical value different from the previously known one. We comment on the effect this change produces on the numerical estimates of the bottom quark ... More
Extended analysis of the "penguin" part of $K\toππ$ amplitudeMar 14 1995We make an attempt to clarify the role of the annihilation or "penguin" mode in the description of the $K\rightarrow\pi\pi$ decay within the Standard Model. The attention is concentrated on new operators in the effective $\Delta S=1$ Hamiltonian and the ... More
Curved space resolution of singularity of fractional D3-branes on conifoldNov 01 2001We construct a supergravity dual to the cascading $SU(N+M) x SU(N)$ supersymmetric gauge theory (related to fractional D3-branes on conifold according to Klebanov et al) in the case when the 3-space is compactified on $S^3$ and in the phase with unbroken ... More
Schwinger-Dyson approach and its application to generate a light composite scalarJan 15 2016Feb 24 2016We discuss the possibility of generating a light composite scalar boson, in a scenario that we may generically call Technicolor, or in any variation of a strongly interacting theory, where by light we mean a scalar composite mass about one order of magnitude ... More
Dynamical gluon mass corrections in heavy quarkonia decaysApr 26 2000Using the expression of the dynamical gluon mass obtained through the operator product expansion we discuss the relevance of gluon mass effects in the decays V -> hadrons (V = J/Psi, Upsilon). Relativistic and radiative corrections are also introduced ... More
Semiclassical rigid strings with two spins in AdS_5Nov 12 2009Semiclassical spinning string states in AdS_5 are, in general, characterised by the three SO(2,4) conserved charges: the energy E and the two spins S_1 and S_2. We discuss several examples of explicit classical solutions for rigid closed strings of (bended) ... More
Search for excited electrons through $γγ$ scatteringAug 10 2012We study the potential of $\gamma \gamma$ option of future high energy linear $e^{+}e^{-}$ colliders to search for excited electrons with spin-1/2. We calculate single production cross sections, give the angular distributions and $f-m^*$ contour plots ... More
A study of spectra of Cyg X-3 observed by BeppoSAXDec 22 2004Jan 10 2005We model the ~1-200 keV spectra of Cygnus X-3 observed by BeppoSAX. The continuum, modeled by Comptonization in a hybrid plasma, is modified by the strongly ionized plasma of the stellar wind of the Wolf-Rayet companion star. Discrete absorption and emission ... More
Quantum Corrections to Bekenstein-Hawking Black Hole Entropy and Gravity Partition FunctionsApr 25 2013Algebraic aspects of the computation of partition functions for quantum gravity and black holes in $AdS_3$ are discussed. We compute the sub-leading quantum corrections to the Bekenstein-Hawking entropy. It is shown that the quantum corrections to the ... More
Chiral expansion of nucleon PDF at $x\sim m_π/M_N$Nov 14 2013Based on the chiral perturbation theory, we investigate the low-energy dynamics of nucleon parton distributions. We show that in different regions of the momentum fraction $x$ the chiral expansion is significantly different. For nucleon parton distributions ... More
Can Electro-Weak $\h$-Term be Observable ?May 14 1993We rederive and discuss the result of the previous paper that in the standard model $\theta$-term related to $W$-boson field can not be induced by weak instantons. This follows from the existence of the fermion zero mode in the instanton field even when ... More
Optimized perturbation theory for bound states: toy model and realistic problemJun 20 1995Within quantum mechanics model we study the problem of resummation of an asymptotic perturbation series for bound state parameters via optimization of the perturbative expansion. A possible application of the method to the positronium lifetime calculation ... More
Ambiguity-free formulation of the Higgs-Kibble modelOct 05 2010A renormalizable ambiguity-free formulation of the Higgs-Kibble model is proposed.
Quantum-Limited Amplification via Reservoir EngineeringNov 01 2013Apr 08 2014We describe a new kind of phase-preserving quantum amplifier which utilizes dissipative interactions in a parametrically-coupled three-mode bosonic system. The use of dissipative interactions provides a fundamental advantage over standard cavity-based ... More
Crossed Andreev reflection in diffusive contactsNov 06 2006Crossed Andreev reflection in multiterminal structures in the diffusive regime is addressed within the quasiclassical Keldysh-Usadel formalism. The elastic cotunneling and crossed Andreev reflection of quasiparticles give nonlocal currents and voltages ... More
Light composite scalar boson from a see-saw mechanism in two-scale TC modelsJun 25 2015We consider the possibility of a light composite scalar boson arising from mass mixing between a relatively light and heavy scalar singlets in a see-saw mechanism expected to occur in two-scale Technicolor (TC) models. A light composite scalar boson can ... More
Limit on the fermion masses in technicolor modelsAug 21 2003Recently it has been pointed out that no limits can be put on the scale of fermion mass generation $(M)$ in technicolor models, because the relation between the fermion masses $(m_f)$ and $M$ depends on the dimensionality of the interaction responsible ... More
Dynamical Symmetry Breaking in a Minimal 3-3-1 ModelOct 11 2012The gauge symmetry breaking in some versions of 3-3-1 models can be implemented dynamically because at the scale of a few TeVs the $U(1)_X$ coupling constant becomes strong. In this work we consider the dynamical symmetry breaking in a minimal $SU(3)_{{}_{TC}}\times ... More
Energy criterion to select the behavior of dynamical masses in technicolor modelsMay 05 2002We propose a quite general ansatz for the dynamical mass in technicolor models. We impose on this ansatz the condition for formation of the tightest composite boson state, or the criterion that it should lead to the deepest minimum of energy. This criterion ... More
Quantum corrections to energy of short spinning string in AdS5Jun 29 2008Feb 02 2009Motivated by desire to shed light on the strong coupling behaviour of anomalous dimensions of "short" gauge theory operators we consider the famous example of folded spinning string in AdS_5 in the limit of small semiclassical spin parameter \S = S/sqrt[lambda]. ... More
A statistical model of three-dimensional anisotropy and intermittency in strong Alfvénic turbulenceMay 24 2016We propose a simple statistical model of three-dimensionally anisotropic, intermittent, strong Alfv\'enic turbulence, incorporating both critical balance and dynamic alignment. Our model is based on log-Poisson statistics for Elsasser-field increments ... More
New results for the missing quantum numbers labeling the quadrupole and octupole boson basisMay 24 2004Oct 27 2004The many $2^k$-pole boson states, $|N_kv_k\alpha_k I_kM_k>$ with $k=2,3$, realize the irreducible representation (IR) for the group reduction chains $SU(2k+1)\supset R_{2k+1}\supset R_3\supset R_2$. They have been analytically studied and widely used ... More
Technicolor models with coupled systems of Schwinger-Dyson equationsFeb 28 2019Mar 15 2019When Technicolor (TC), QCD, Extended Technicolor (ETC) and other interactions become coupled through their different Schwinger-Dyson equations, the solution of these equations are modified in comparison with the ones of the isolated equations. The change ... More
One- and many-body effects on mirages in quantum corralsAug 27 2002May 23 2003Recent interesting experiments used scanning tunneling microscopy to study systems involving Kondo impurities in quantum corrals assembled on Cu or noble metal surfaces. The solution of the two-dimensional one-particle Schrodinger equation in a hard wall ... More
Gravitation Field Dynamics in Jeans TheoryFeb 02 2016Closed system of time equations for nonrelativistic gravitation field and hydrodynamic medium was obtained by taking into account binary correlations of the field, which is the generalization of Jeans theory. Distribution function of the systemwas built ... More
Matrix Model on Z-OrbifoldMar 24 2002Dec 26 2002Six dimensional compactification of the type IIA matrix model on the ${\bf Z}$-orbifold is studied. Introducing a ${\bf Z}_{3}$ symmetry properly on the three mirror images of fields in the $N$-body system of the supersymmetric D0 particles, the action ... More
Uniform semiglobal practical asymptotic stability for non-autonomous cascaded systems and applicationsMar 02 2005Feb 01 2006It is due to the modularity of the analysis that results for cascaded systems have proved their utility in numerous control applications as well as in the development of general control techniques based on ``adding integrators''. Nevertheless, the standing ... More
The Asymptotics of the Correlations Functions in $(1+1)d$ Quantum Field Theory From Finite Size Effects in Conformal TheoriesJan 08 1992Using the finite-size effects the scaling dimensions and correlation functions of the main operators in continuous and lattice models of 1d spinless Bose-gas with pairwise interaction of rather general form are obtained. The long-wave properties of these ... More
Frustrated trimer chain model and Cu3Cl6(H2O)2 2H8C4SO2 in a magnetic fieldMay 24 2000May 08 2001Recent magnetization and susceptibility measurements on Cu3Cl6(H2O)2 2H8C4SO2 by Ishii [J. Phys. Soc. Jpn. 69, 340 (2000)] have demonstrated the existence of a spin gap. In order to explain the opening of a spin gap in this copper-trimer system, ... More
Two-Loop Corrections to Bhabha ScatteringJan 14 2005Jul 04 2005The two-loop radiative photonic corrections to the Bhabha scattering are computed in the leading order of the small electron mass expansion up to nonlogarithmic term. After including the soft photon bremsstrahlung we obtain the infrared finite result ... More
Instantons and Non-Perturbative Dynamics of N=2 Supersymmetric Abelian Gauge Theories in Two DimensionsOct 29 1997Jun 19 1998We study N=2 supersymmetric Abelian gauge model with the Fayet-Iliopoulos term and an arbitrary number of chiral matter multiplets in two dimensions. By analyzing the instanton contribution we compute the non-perturbative corrections to the mass spectrum ... More
Two-Loop Photonic Corrections to Massive Bhabha ScatteringAug 11 2005Nov 28 2005We describe the details of the evaluation of the two-loop radiative photonic corrections to Bhabha scattering. The role of the corrections in the high-precision luminosity determination at present and future electron-positron colliders is discussed.
Top quark threshold production in $γγ$ collisions: current theoretical issuesSep 29 2000The top quark-antiquark pair threshold production at future High Energy Photon Colliders is considered in view of the recent advances in the theoretical description of the nonrelativistic heavy quark dynamics.
The Synthetic-Oversampling Method: Using Photometric Colors to Discover Extremely Metal-Poor StarsMay 07 2015Extremely metal-poor (EMP) stars ([Fe/H] < -3.0 dex) provide a unique window into understanding the first generation of stars and early chemical enrichment of the Universe. EMP stars are exceptionally rare, however, and the relatively small number of ... More
Exact unitary transformation for Rashba rings in magnetic and electric fieldsDec 25 2015Jan 05 2016An exact solution for single electron states on mezoscopic rings with the Rashba coupling and in the presence of external magnetic and electric fields is derived by means of a unitary transformation. The transformation maps the model to a bare ring, which ... More
Stochastic Inflation: New ResultsJun 14 1994This is an old article which has never been posted for public use and which only appeard in a relatively hard-to-get Proceedings of the Sakharov Conference in Moscow (May, 1991). The subject of this article has received a lot of attention in last two ... More
Logarithmic Potential Model of Quigg and Rosner as a Generalization of Naive Quark ModelJun 26 2000Exploiting the explicit mass formulae for logarithmic potential model of Quigg and Rosner it is shown that at least on the level of mass-relations this model reproduces the naive quark model relations and generalizes the last one in case of highly non-trivial ... More
Global anomaly and a family of structures on fold product of complex two-cyclesOct 27 2009We propose a new set of IIB type and eleven-dimensional supergravity solutions which consists of the $n$-fold product of two-spaces ${\bf H}^n/\Gamma$ (where ${\bf H}^n$ denotes the product of $n$ upper half-planes $H^2$ equipped with the co-compact action ... More
Universal Racah matrices and adjoint knot polynomials. I. Arborescent knotsNov 29 2015By now it is well established that the quantum dimensions of descendants of the adjoint representation can be described in a universal form, independent of a particular family of simple Lie algebras. The Rosso-Jones formula then implies a universal description ... More
Proving AGT relations in the large-c limitSep 18 2009In the limit of large central charge $c$ the 4-point Virasoro conformal block becomes a hypergeometric function. It is represented by a sum of chiral Nekrasov functions, which can also be explicitly evaluated. In this way the known proof of the AGT relation ... More
The Power of Nekrasov FunctionsAug 15 2009The recent AGT suggestion to use the set of Nekrasov functions as a basis for a linear decomposition of generic conformal blocks works very well not only in the case of Virasoro symmetry, but also for conformal theories with extended chiral algebra. This ... More
p,q-Duality and Hamiltonian Flows in the Space of Integrable Systems or Integrable Systems as Canonical Transforms of the Free OnesJul 12 2001Jan 09 2002Variation of coupling constants of integrable system can be considered as canonical transformation or, infinitesimally, a Hamiltonian flow in the space of such systems. Any function $T(\vec p, \vec q)$ generates a one-parametric family of integrable systems ... More
On Renormalization Group in Abstract QFTMay 30 2000The basics of RG equations for generic partition functions are briefly reviewed, keeping in mind an application to the Polyakov-de Boer-Verlindes description of the holomorphic RG flow.
Structure of Stationary Strong Imbalanced TurbulenceApr 16 2009Jul 16 2009In this paper we systematically study the spectrum and structure of incompressible MHD turbulence by means of high resolution direct numerical simulations. We considered both balanced and imbalanced (cross-helical) cases and simulated sub-Alfvenic as ... More
Turbulence Spectra from Doppler-broadened Spectral Lines: Tests of the Velocity Channel Analysis and Velocity Coordinate Spectrum TechniquesNov 05 2008Nov 07 2008Turbulent motions induce Doppler shifts of observable emission and absorption lines motivating studies of turbulence using precision spectroscopy. We provide the numerical testing of the two most promising techniques, Velocity Channel Analysis (VCA) and ... More
Bicrossproduct construction versus Weyl-Heisenberg algebraApr 26 2012We are focused on detailed analysis of the Weyl-Heisenberg algebra in the framework of bicrossproduct construction. We argue that however it is not possible to introduce full bialgebra structure in this case, it is possible to introduce non-counital bialgebra ... More
Manifestation of marginal Fermi liquid and phonon excitations in photoemision experiments of cuprate superconductorsOct 19 2001Recent ARPES experiments in cuprates superconductors show a kink in the electron dispersion near the Fermi energy. This kink coexists with a linear frequency dependence of the imaginary part of the electron self-energy. In this paper we show that both ... More
Coarsening versus pattern formationJan 22 2015Mar 13 2015It is known that similar physical systems can reveal two quite different ways of behavior, either coarsening, which creates a uniform state or a large-scale structure, or formation of ordered or disordered patterns, which are never homogenized. We present ... More