Results for "Ali Rajabpour"

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Thermal conductivity and thermal rectification of nanoporous graphene: A molecular dynamics simulationJun 11 2019Using non-equilibrium molecular dynamics (NEMD) simulation, we study thermal properties of the so-called nanoporous graphene (NPG) sheet which contains a series of nanoporous in an ordered way and was synthesized recently (Science 360 (2018), 199). The ... More
Thermal transport across grain boundaries in polycrystalline silicene: a multiscale modelingJan 03 2019During the fabrication process of large scale silicene through common chemical vapor deposition (CVD) technique, polycrystalline films are quite likely to be produced, and the existence of Kapitza thermal resistance along grain boundaries could result ... More
Thermal transport in silicene nanotubes: Effects of length, grain boundary and strainJan 03 2019Thermal transport behavior in silicene nanotubes has become more important due to the application of these promising nanostructures in the engineering of next-generation nanoelectronic devices. We apply non-equilibrium molecular dynamics (NEMD) simulations ... More
Perturbed Logarithmic CFT and Integrable ModelsOct 09 2005Feb 05 2006Perturbation of logarithmic conformal field theories is investigated using Zamolodchikov's method. We derive conditions for the perturbing operator, such that the perturbed model be integrable. We also consider an example where integrable models arise ... More
Phonon Heat Conduction in Corrugated Silicon Nanowires Below the Casimir LimitFeb 18 2013Apr 17 2013The thermal conductance of straight and corrugated monocrystalline silicon nanowires has been measured between 0.3 K and 5 K. The difference in the thermal transport between corrugated nanowires and straight ones demonstrates a strong reduction in the ... More
Inter-layer and Intra-layer Heat Transfer in Bilayer/Monolayer Graphene van der Waals Heterostructure: Is There a Kapitza Resistance Analogous?Nov 24 2017Van der Waals heterostructures have exhibited interesting physical properties. In this paper, heat transfer in hybrid coplanar bilayer/monolayer (BL-ML) graphene, as a model layered van der Waals heterostructure, was studied using non-equilibrium molecular ... More
The effect of water/carbon interaction strength on interfacial thermal resistance and the surrounding molecular nanolayer of CNT and graphene nanoparticlesJan 10 2019Heat transfer at the liquid/solid interface, especially at the nanoscale, has enormous importance in nanofluids. This study investigates liquid/solid interfacial thermal resistance and structure of the formed molecular nanolayer around a carbon-based ... More
Thermal transport at a nanoparticle-water interface: A molecular dynamics and continuum modeling studyJan 10 2019Heat transfer between a silver nanoparticle and surrounding water has been studied using molecular dynamics (MD) simulations. The thermal conductance (Kapitza conductance) at the interface between a nanoparticle and surrounding water has been calculated ... More
Some Aspects of c=-2 TheoryOct 30 2006Nov 19 2006We investigate some aspects of the c=-2 logarithmic conformal field theory. These include the various representations related to this theory, the structures which come out of the Zhu algebra and the W algebra related to this theory. We try to find the ... More
Abelian Sandpile Model: a Conformal Field Theory Point of ViewOct 18 2004In this paper we derive the scaling fields in $c=-2$ conformal field theory associated with weakly allowed clusters in abelian sandpile model and show a direct relation between the two models.
Classification of the sign of the critical Casimir force in two dimensional systemsSep 20 2016We classify the sign of the critical Casimir force between two finite objects separated by a large distance in the two dimensional systems that can be described by conformal field theory (CFT). In particular, we show that as far as the smallest scaling ... More
Entanglement entropy after a partial projective measurement in $1+1$ dimensional conformal field theories: exact resultsDec 12 2015Apr 12 2016We calculate analytically the R\'enyi bipartite entanglement entropy $S_{\alpha}$ of the ground state of $1+1$ dimensional conformal field theories (CFT) after performing a projective measurement in a part of the system. We show that the entanglement ... More
Finite size corrections to scaling of the formation probabilities and the Casimir effect in the conformal field theoriesJul 24 2016We calculate formation probabilities of the ground state of the finite size quantum critical chains using conformal field theory (CFT) techniques. In particular, we calculate the formation probability of one interval in the finite open chain and also ... More
Formation probabilities in quantum critical chains and Casimir effectDec 03 2015Jan 26 2016We find a connection between logarithmic formation probabilities of two disjoint intervals of quantum critical spin chains and the Casimir energy of two aligned needles in two dimensional classical critical systems. Using this connection we provide a ... More
Fate of the area-law after partial measurement in quantum field theoriesMar 26 2015Mar 28 2016We calculate numerically the R\'enyi bipartite entanglement entropy of the ground state of Klein-Gordon field theory (coupled harmonic oscillators) after fixing the position (partial measurement) of some of the oscillators in $d=1,2$ and $3$ dimensions. ... More
Post measurement bipartite entanglement entropy in conformal field theoriesJan 30 2015Aug 06 2015We derive exact formulas for bipartite von Neumann entanglement entropy after partial projective local measurement in $1+1$ dimensional conformal field theories with periodic and open boundary conditions. After defining the set up we will check numerically ... More
Winding Number of Fractional Brownian MotionJul 23 2008Feb 26 2009We find the exact winding number distribution of Riemann-Liouville fractional Brownian motion for large times in two dimensions using the propagator of a free particle. The distribution is similar to the Brownian motion case and it is of Cauchy type. ... More
Quantum quench in long-range field theoriesSep 23 2014Jan 21 2015We study equilibration properties of observables in long-range field theories after the mass quench in $d=1,2$ and $3$ dimensions. We classify the regimes where we expect equilibration or its absence in different dimensions. In addition we study the effect ... More
Conformal symmetry in non-local field theoriesMar 18 2011Jun 25 2011We have shown that a particular class of non-local free field theory has conformal symmetry in arbitrary dimensions. Using the local field theory counterpart of this class, we have found the Noether currents and Ward identities of the translation, rotation ... More
Area Distribution of Elastic Brownian MotionJun 17 2009Nov 14 2009We calculate the excursion and meander area distributions of the elastic Brownian motion by using the self adjoint extension of the Hamiltonian of the free quantum particle on the half line. We also give some comments on the area of the Brownian motion ... More
Bessel Process and Conformal Quantum MechanicsJun 09 2009Different aspects of the connection between the Bessel process and the conformal quantum mechanics (CQM) are discussed. The meaning of the possible generalizations of both models is investigated with respect to the other model, including self adjoint ... More
Loop models for CFTsJun 27 2008Feb 26 2009By interpreting the fusion matrix as an adjacency matrix we associate a loop model to every primary operator of a generic conformal field theory. The weight of these loop models is given by the quantum dimension of the corresponding primary operator. ... More
Boundary conformal field theories and loop modelsAug 01 2008Apr 20 2009We propose a systematic method to extract conformal loop models for rational conformal field theories (CFT). Method is based on defining an ADE model for boundary primary operators by using the fusion matrices of these operators as adjacency matrices. ... More
Recent Results on Photoproduction of Vector Mesons and Mass Dependent Pomeron TrajectorySep 13 2002It is shown that the recent results on photoproduction of vector mesons can be naturally explained by using a mass dependent pomeron trajectory.
Amenability of groups and semigroups characterized by ConfigurationJan 25 2015In 2005, Abdollahi and Rejali, studied the relations between paradoxical decompositions and configurations for semigroups. In the present paper, we introduce another concept of amenability on semigroups and groups which includes amenability of semigroups ... More
Error Correction Coding Meets Cyber-Physical Systems: Message-Passing Analysis of Self-Healing Interdependent NetworksSep 25 2016Coupling cyber and physical systems gives rise to numerous engineering challenges and opportunities. An important challenge is the contagion of failure from one system to another, which can lead to large-scale cascading failures. However, the \textit{self-healing} ... More
Quantum Quench of the trap frequency in the harmonic Calogero modelJul 29 2013Nov 27 2013We consider a quantum quench of the trap frequency in a system of bosons interacting through an inverse-square potential and confined in a harmonic trap (the harmonic Calogero model). We determine exactly the initial state in terms of the post-quench ... More
Entanglement entropy of two disjoint intervals from fusion algebra of twist fieldsDec 06 2011We study the entanglement and Renyi entropies of two disjoint intervals in minimal models of conformal field theory. We use the conformal block expansion and fusion rules of twist fields to define a systematic expansion in the elliptic parameter of the ... More
Explicit Renormalization Group for D=2 random bond Ising model with long-range correlated disorderSep 23 2006Sep 25 2007We investigate the explicit renormalization group for fermionic field theoretic representation of two-dimensional random bond Ising model with long-range correlated disorder. We show that a new fixed point appears by introducing a long-range correlated ... More
Discretely Holomorphic Parafermions in Lattice Z(N) ModelsAug 28 2007Nov 20 2007We construct lattice parafermions - local products of order and disorder operators - in nearest-neighbor Z(N) models on regular isotropic planar lattices, and show that they are discretely holomorphic, that is they satisfy discrete Cauchy-Riemann equations, ... More
Formation probabilities and Shannon information and their time evolution after quantum quench in transverse-field XY-chainNov 19 2015Mar 28 2016We first provide a formula to calculate the probability of occurrence of different configurations (formation probabilities) in a generic free fermion system. We then study the scaling of these probabilities with respect to the size in the case of critical ... More
Entanglement entropy after selective measurements in quantum chainsAug 14 2016Aug 27 2016We study bipartite post measurement entanglement entropy after selective measurements in quantum chains. We first study the quantity for the critical systems that can be described by conformal field theories. We find a connection between post measurement ... More
Area law and universality in the statistics of subsystem energyJun 06 2018Jan 27 2019We introduce R\'enyi entropy of a subsystem energy as a natural quantity which closely mimics the behavior of the entanglement entropy and can be defined for all the quantum many body systems. For this purpose, consider a quantum chain in its ground state ... More
Spin interfaces in the Ashkin-Teller model and SLENov 14 2011We investigate the scaling properties of the spin interfaces in the Ashkin-Teller model. These interfaces are a very simple instance of lattice curves coexisting with a fluctuating degree of freedom, which renders the analytical determination of their ... More
Ashkin-Teller model on the iso-radial graphsMar 31 2010We find the critical surface of the Ashkin-Teller model on the generic iso-radial graphs by using the results for the anisotropic Ashkin-teller model on the square lattice. Different geometrical aspects of this critical surface are discussed, especially ... More
Message Passing for Analysis and Resilient Design of Self-Healing Interdependent Cyber-Physical NetworksJun 03 2016Coupling cyber and physical systems gives rise to numerous engineering challenges and opportunities. An important challenge is the contagion of failure from one system to another, that can lead to large scale cascading failures. On the other hand, self-healing ... More
Message Passing for Analysis and Resilient Design of Self-Healing Interdependent Cyber-Physical NetworksJun 03 2016Dec 29 2016Coupling cyber and physical systems gives rise to numerous engineering challenges and opportunities. An important challenge is the contagion of failure from one system to another, that can lead to large scale cascading failures. On the other hand, self-healing ... More
Discrete holomorphic parafermions in the Ashkin-Teller model and SLESep 17 2010Nov 24 2010We find discrete holomorphic parafermions of the Ashkin-Teller model on the critical line, by mapping appropriate interfaces of the model to the $O(n=1)$ model. We give support to the conjecture that the curve created by the insertion of parafermionic ... More
Conformal Curves in Potts Model: Numerical CalculationMar 16 2010We calculated numerically the fractal dimension of the boundaries of the Fortuin-Kasteleyn clusters of the $q$-state Potts model for integer and non-integer values of $q$ on the square lattice. In addition we calculated with high accuracy the fractal ... More
Finite Size Scaling and Conformal CurvesNov 06 2005In this letter we investigate the finite size scaling effect on SLE($\kappa,\rho$) and boundary conformal field theories and find the effect of fixing some boundary conditions on the free energy per length of SLE($\kappa,\rho$). As an application, we ... More
Return amplitude after a quantum quench in the XY chainMay 03 2019We determine an exact formula for the transition amplitude between any two arbitrary eigenstates of the local $z$-magnetization operators in the quantum XY chain. We further use this formula to obtain an analytical expression for the return amplitude ... More
Formules explicites du noyau de la chaleur sur l'espace projectif quaternioniqueMar 25 2011In this note we give an explicit integral representation and an expanssion for the heat kernel $ H_n(t;x,y)$ associated to Fubini-Study Laplacians on quaternionic projective spaces $\mathbb{P}^n(\mathbb H)$, $n \geq 1$. This was possible by establishing ... More
The Effects of Cultural dimensions and Demographic Characteristics on E-learning AcceptanceJul 06 2016This study aims to develop and test an amalgamated conceptual framework based on Technology Acceptance Model (TAM) and other models from social psychology, such as theory of reasoned action and TAM2 that captures the salient factors influencing the user ... More
D-instantons in Klebanov-Witten modelMar 01 2016May 03 2016We study D-instanton solutions in type IIB supergravity on $AdS_5\times T^{1,1}$, which has a dual ${\cal N}=1$ $SU(N)\times SU(N)$ super Yang-Mills theory. Apart from ordinary D(-1)-brane instantons, we discuss wrapped D1-branes over minimal 2-cycles ... More
A Characterization of Modules with Cyclic SocleMay 03 2015In 2009, J. Wood [15] proved that Frobenius bimodules have the extension property for symmetrized weight compositions. Later, in [9], it was proved that having a cyclic socle is sufficient for satisfying the property, while the necessity remained an open ... More
Moser functions and fractional Moser-Trudinger type inequalitiesOct 22 2015We improve the sharpness of some fractional Moser-Trudinger type inequalities, particularly those studied by Lam-Lu and Martinazzi. As an application, improving upon works of Adimurthi and Lakkis, we prove the existence of weak solutions to the problem ... More
Structure of conformal metrics on $\mathbb{R}^n$ with constant $Q$-curvatureApr 27 2015In this article we study the nonlocal equation \begin{align} (-\Delta)^{\frac{n}{2}}u=(n-1)!e^{nu}\quad \text{in $\mathbb{R}^n$}, \quad\int_{\mathbb{R}^n}e^{nu}dx<\infty, \notag \end{align} which arises in the conformal geometry. Inspired by the previous ... More
Fluctuations of Quantum Fields in a Classical Background and ReheatingSep 15 2009Jan 05 2010We consider the particle creation process associated with a quantum field \chi in a time-dependent, homogeneous and isotropic, classical background. It is shown that the field square \chi^2, the energy density and the pressure of the created particles ... More
Volume Stabilization and Acceleration in Brane Gas CosmologyMay 11 2004Aug 13 2004We investigate toy cosmological models in (1+m+p)-dimensions with gas of p-branes wrapping over p-compact dimensions. In addition to winding modes, we consider the effects of momentum modes corresponding to small vibrations of branes and find that the ... More
Scalar Absorption by Noncommutative D3-branesNov 23 1999Jan 30 2000The classical cross section for low energy absorption of the RR-scalar by a stack of noncommutative D3-branes in the large NS B-field limit is calculated. In the spirit of AdS/CFT correspondence, this cross section is related to two point function of ... More
Quantum Mechanical Breakdown of Perfect Homogeneity in Reheating After InflationFeb 15 2008Oct 17 2008In the context of quantum fields in time dependent classical backgrounds, we notice that the number of created particles with a given momentum largely deviates about its mean value. Guided with this observation we use a complete orthonormal family of ... More
Supergravity Solutions for Harmonic, Static and Flux S-BranesJan 27 2006Feb 01 2006We seek S-brane solutions in D=11 supergravity which can be characterized by a harmonic function H on the flat transverse space. It turns out that the Einstein's equations force H to be a linear function of the transverse coordinates. The codimension ... More
Brane Gases and Stabilization of Shape Moduli with Momentum and Winding StressApr 26 2005Sep 06 2005In a toy model with gases of membranes and strings wrapping over a two-dimensional internal torus, we study the stabilization problem for the shape modulus. It is observed that winding modes of partially wrapped strings and momentum modes give rise to ... More
On the Geometric Properties of AdS InstantonsMay 31 1999Jul 15 1999According to the positive energy conjecture of Horowitz and Myers, there is a specific supergravity solution, AdS soliton, which has minimum energy among all asymptotically locally AdS solutions with the same boundary conditions. Related to the issue ... More
Active Invisibility Cloaks in One DimensionApr 05 2015Jun 09 2015We outline a general method of constructing finite-range cloaking potentials which render a given finite-range real or complex potential $v(x)$ unidirectionally reflectionless or invisible at a wavenumber $k_0$ of our choice. We give explicit analytic ... More
Physics of Spectral SingularitiesDec 01 2014Apr 05 2015Spectral singularities are certain points of the continuous spectrum of generic complex scattering potentials. We review the recent developments leading to the discovery of their physical meaning, consequences, and generalizations. In particular, we give ... More
Adiabatic Series Expansion and Higher-Order Semiclassical Approximations in Scattering TheoryFeb 26 2014The scattering properties of any complex scattering potential, v:R -> C, can be obtained from the dynamics of a particular non-unitary two-level quantum system S_v. The application of the adiabatic approximation to S_v yields a semiclassical treatment ... More
Nonlinear Spectral Singularities for Localized NonlinearitiesMar 11 2013May 31 2013We introduce a notion of spectral singularity that applies for a general class of nonlinear Schreodinger operators involving a confined nonlinearity. The presence of the nonlinearity does not break the parity-reflection symmetry of spectral singularities ... More
Semiclassical Analysis of Spectral Singularities and Their Applications in OpticsMay 23 2011Motivated by possible applications of spectral singularities in optics, we develop a semiclassical method of computing spectral singularities. We use this method to examine the spectral singularities of a planar slab gain medium whose gain coefficient ... More
Is Weak Pseudo-Hermiticity Weaker than Pseudo-Hermiticity?May 12 2006Nov 28 2006For a weakly pseudo-Hermitian linear operator, we give a spectral condition that ensures its pseudo-Hermiticity. This condition is always satisfied whenever the operator acts in a finite-dimensional Hilbert space. Hence weak pseudo-Hermiticity and pseudo-Hermiticity ... More
Comment on ``On Existence of a Biorthonormal Basis Composed of Eigenvectors of Non-Hermitian Operators [quant-ph/0603075]''Mar 10 2006We point out that T. Tanaka's recent criticism [quant-ph/0603075] of the results of J. Math. Phys. 43, 3944 (2002) [math-ph/0203005] is based on an assumption which was never made in the latter paper, namely that the diagonalizability of an operator implies ... More
Pseudo-Hermiticity, PT-symmetry, and the Metric OperatorAug 29 2005The main achievements of Pseudo-Hermitian Quantum Mechanics and its distinction with the indefinite-metric quantum theories are reviewed. The issue of the non-uniqueness of the metric operator and its consequences for defining the observables are discussed. ... More
Erratum: Pseudo-Hermiticity for a class of nondiagonalizable Hamiltonians [J. Math. Phys. 43, 6343 (2002); math-ph/0207009]Jan 22 2003An error in the paper [J. Math. Phys. 43, 6343 (2002); math-ph/0207009] is corrected. Further explanation is given.
Pseudo-Hermiticity versus PT-Symmetry III: Equivalence of pseudo-Her miticity and the presence of antilinear symmetriesMar 04 2002May 07 2002We show that a diagonalizable (non-Hermitian) Hamiltonian H is pseudo-Hermitian if and only if it has an antilinear symmetry, i.e., a symmetry generated by an invertible antilinear operator. This implies that the eigenvalues of H are real or come in complex ... More
Eigenvalue Problem for Schroedinger Operators and Time-Dependent Harmonic OscillatorJun 26 1997It is shown that the eigenvalue problem for the Hamiltonians of the standard form, $H=p^2/(2m)+V(x)$, is equivalent to the classical dynamical equation for certain harmonic oscillators with time-dependent frequency. This is another indication of the central ... More
Perturbative Unidirectional InvisibilityJul 08 2015We outline a general perturbative method of evaluating scattering features of finite-range complex potentials and use it to examine complex perturbations of a rectangular barrier potential. In optics, these correspond to modulated refractive index profiles ... More
Spectral Singularities and CPA-Laser Action in a Weakly Nonlinear PT-Symmetric Bilayer SlabApr 07 2014We study optical spectral singularities of a weakly nonlinear PT-symmetric bilinear planar slab of optically active material. In particular, we derive the lasing threshold condition and calculate the laser output intensity. These reveal the following ... More
A Hamiltonian Formulation of the Pais-Uhlenbeck Oscillator that Yields a Stable and Unitary Quantum SystemAug 27 2010We offer a new Hamiltonian formulation of the classical Pais-Uhlenbeck Oscillator and consider its canonical quantization. We show that for the non-degenerate case where the frequencies differ, the quantum Hamiltonian operator is a Hermitian operator ... More
Resonance Phenomenon Related to Spectral Singularities, Complex Barrier Potential, and Resonating WaveguidesAug 12 2009Jun 02 2010A peculiar property of complex scattering potentials is the appearance of spectral singularities. These are energy eigenvalues for certain scattering states that similarly to resonance states have infinite reflection and transmission coefficients. This ... More
Metric Operator in Pseudo-Hermitian Quantum Mechanics and the Imaginary Cubic PotentialAug 26 2005Jul 26 2006We present a systematic perturbative construction of the most general metric operator (and positive-definite inner product) for quasi-Hermitian Hamiltonians of the standard form, H= p^2/2 + v(x), in one dimension. We show that this problem is equivalent ... More
Pseudo-Hermiticity and Generalized PT- and CPT-SymmetriesSep 10 2002Nov 28 2002We study certain linear and antilinear symmetry generators and involution operators associated with pseudo-Hermitian Hamiltonians and show that the theory of pseudo-Hermitian operators provides a simple explanation for the recent results of Bender, Brody ... More
Comment on Identical Motion in Classical and Quantum MechanicsSep 30 1999Makowski and Konkel [Phys. Rev. A 58, 4975 (1998)] have obtained certain classes of potentials which lead to identical classical and quantum Hamilton-Jacobi equations. We obtain the most general form of these potential.
Noncyclic geometric phase and its non-Abelian generalizationSep 30 1999We use the theory of dynamical invariants to yield a simple derivation of noncyclic analogues of the Abelian and non-Abelian geometric phases. This derivation relies only on the principle of gauge invariance and elucidates the existing definitions of ... More
Comment on Cyclic quantum-evolution dependence on the Hamiltonian and geometric phaseJun 20 1996It is shown that the analysis and the main result of the article by L-A. Wu [Phys. Rev. A 53, 2053 (1996)] are completely erroneous.
A Proof of The Fundamental Theorem of AlgebraSep 05 2005Feb 12 2008We give a proof for the fundamental theorem of algebra,using the Fredholm index phenomena
A Note On Application Of Singular RescalingSep 22 2004Using Singular Rescaling We Prove Some Bifurcation Results. This note Presents short proofs for some Bifurcation results which had been appeared with other Authors
Theoretical and Numerical Analysis of Approximate Dynamic Programming with Approximation ErrorsDec 18 2014May 15 2015This study is aimed at answering the famous question of how the approximation errors at each iteration of Approximate Dynamic Programming (ADP) affect the quality of the final results considering the fact that errors at each iteration affect the next ... More
Optimal Triggering of Networked Control SystemsDec 17 2014The problem of resource allocation of nonlinear networked control systems is investigated, where, unlike the well discussed case of triggering for stability, the objective is optimal triggering. An approximate dynamic programming approach is developed ... More
Feedback Solution to Optimal Switching Problems with Switching CostNov 17 2014The problem of optimal switching between nonlinear autonomous subsystems is investigated in this study where the objective is not only bringing the states to close to the desired point, but also adjusting the switching pattern, in the sense of penalizing ... More
Size and structure of large $(s,t)$-union intersecting familiesMar 06 2019An $(s,t)$-union intersecting family is a family of $k$-sets on an $n$-set $X$ such that for each $\{A_1,\ldots,A_s\},\{B_1,\ldots,B_t\}$ in this family, $\left(\cup_{i=1}^s A_i\right)\cap\left(\cup_{i=1}^tB_i\right)\neq \varnothing.$ For $\beta< s(k-1)$, ... More
Sequential Consistency and Concurrent Data StructuresJun 16 2015Linearizability, the de facto correctness condition for concurrent data structure implementations, despite its intuitive appeal is known to lead to poor scalability. This disadvantage has led researchers to design scalable data structures satisfying consistency ... More
Plane Symmetric, Cylindrically Symmetric and Spherically Symmetric Black Holes Solutions of Einstein Field EquationsOct 19 2014Dec 30 2014In this paper we present Plane symmetric, Cylindrically Symmetric and Spherically Symmetric Black hole or Vacuum solutions of Einstein Field Equations(EFEs). Some of these solutions are new which we have not seen in the literature. This calculation will ... More
On $iε$ Prescription in CosmologyOct 29 2018Mar 25 2019This is a technical note on the $i\epsilon$ prescription in cosmology where we consider a self-interacting scalar field in the Poincare patch of the de Sitter space whose Hamiltonian has explicit time dependence. We use both path integral and operator ... More
On the long time behavior of time relaxation model of fluidsMar 29 2019The time relaxation model, which is family of high accuracy turbulence models, has proven to be effective in regularization of Navier Stokes Equations. The model belongs to the class of Large Eddy Simulation models, and is derived by adding a linear time ... More
On a critical Leray$-α$ model of turbulenceMar 03 2011This paper aims to study a family of Leray-$\alpha$ models with periodic bounbary conditions. These models are good approximations for the Navier-Stokes equations. We focus our attention on the critical value of regularization "$\theta$" that garantees ... More
Large Eddy Simulation for Turbulent Flows with Critical RegularizationJul 07 2011In this paper, we establish the existence of a unique "regular" weak solution to the Large Eddy Simulation (LES) models of turbulence with critical regularization. We first consider the critical LES for the Navier-Stokes equations and we show that its ... More
Qubit-Qutrit ($2 \otimes 3$) quantum systems: An investigation of some quantum correlations under collective dephasingMay 14 2019We revisit qubit-qutrit quantum systems under collective dephasing and answer some of the questions which have not been asked and addressed so far in the literature. In particular, we examine the possibilities of non-trivial phenomena of {\it time-invariant} ... More
Freezing dynamics of entanglement and nonlocality for qutrit-qutrit ($3 \otimes 3$) quantum systemsOct 02 2018We examine the possibilities of non-trivial phenomena of time-invariant entanglement and freezing dynamics of entanglement for qutrit-qutrit quantum systems. We find no evidence for time-invariant entanglement, however, we do observe that quantum states ... More
Freezing dynamics of genuine entanglement and loss of genuine nonlocality under collective dephasingMar 29 2017We study the dynamics of genuine multipartite entanglement for quantum systems upto four qubits interacting with general collective dephasing process. Using a computable entanglement monotone for multipartite systems, we observe the feature of freezing ... More
Distillability sudden death in qutrit-qutrit systems under global decoherenceNov 04 2009Recently Song {\it et al}., Phys. Rev. A {\bf 80}, 012331 (2009), have discovered that certain two-qutrit entangled states interacting with multi-local decoherence undergo distillability sudden death whereas their locally equivalent states do not exhibit ... More
On the semi-proper orientations of graphsMay 08 2019A {\it semi-proper orientation} of a given graph $G$ is a function $(D,w)$ that assigns an orientation $D(e)$ and a positive integer weight $ w(e)$ to each edge $e$ such that for every two adjacent vertices $v$ and $u$, $S_{(D,w)}(v) \neq S_{(D,w)}(u) ... More
Rare B-Meson Decays at the CrossroadsJul 17 2016Experimental era of rare $B$-decays started with the measurement of $B \to K^* \gamma$ by CLEO in 1993, followed two years later by the measurement of the inclusive decay $B \to X_s \gamma$, which serves as the standard candle in this field. The frontier ... More
Theory Overview on SpectroscopyAug 10 2011A theoretical overview of the exotic spectroscopy in the charm and beauty quark sector is presented. These states are unexpected harvest from the $e^+e^-$ and hadron colliders and a permanent abode for the majority of them has yet to be found. We argue ... More
Theory of Rare B DecaysSep 30 1997Oct 06 1997We discuss some selected topics in rare B decays in the context of the standard model and compare theoretical estimates with available data. Salient features of the perturbative-QCD and power corrections in the decay rate for $B \to X_s + \gamma$ are ... More
Rare Radiative $B$ Decays in the Standard ModelAug 21 1995A status report on the theory and phenomenology of rare radiative $B$ decays in the standard model is presented with emphasis on the measured decays $B \to X_s \gamma$ and $B \to K^* \gamma$. Standard model is in agreement with experiments though this ... More
The heat equation for the Dirichlet fractional Laplacian with Hardy's potentials: properties of minimal solutions and blow-upJun 06 2016Local and global properties of minimal solutions for the heat equation generated by the Dirichlet fractional Laplacian negatively perturbed by Hardy's potentials on open subsets of $\R^d$ are analyzed. As a byproduct we obtain instantaneous blow-up of ... More
Stably ergodic diffeomorphisms which are not partially hyperbolicJun 08 2002We show stable ergodicity of a class of conservative diffeomorphisms which do not have any hyperbolic invariant subbundle. Moreover the uniqueness of SRB measures for non-conservative $C^1$ perturbations of such diffeomorphisms. This class contains strictly ... More
A note on power generalized extreme value distribution and its propertiesNov 30 2017Similar to the generalized extreme value (GEV) family, the generalized extreme value distributions under power normalization are introduced by Roudsari (1999) and Barakat et al. (2013). In this article, we study the asymptotic behavior of GEV laws under ... More
Some algebraic properties of $F(2O_k)$ graphsMay 25 2019In this research, the notation of the folded graph of $2O_k$ will be defined and denoted by $F(2O_k)$, as the graph whose vertex set is identical to the vertex set of $2O_k$, and with edge set $E_2 = E_1 \cup\{\{(v, i), (v, i^c)\} | (v, i), (v, i^c) \in ... More
A Note on Positive Zero Divisors in C* AlgebrasJan 13 2013May 15 2013In this paper we concern with positive zero divisors in $C^{*}$ algebras. By means of zero divisors, we introduce a hereditary invariant for $C^{*}$ algebras. Using this invariant, we give an example of a $C^{*}$ algebra $A$ and a $C^{*}$ sub algebra ... More