Nisoli, Cristiano, Abraham, Douglas, Lookman, Turab, Saxena, Avadh
We present a general framework to explore thermally activated failures in quasi one dimensional systems. We apply it to the collapse of carbon nanotubes, the formation of bottlenecks in nanowires,...
Bilayer graphene Origami: curvature-induced p-n junctions (2009)
Joglekar, Yogesh N., Saxena, Avadh
A massive quantum particle on a two-dimensional curved surface experiences a surface-geometry induced attractive potential that is characterized by the radii of curvature at a given point. With...
Thermal Stability of Strained Nanowires (2009)
Nisoli, Cristiano, Abraham, Douglas, Lookman, Turab, Saxena, Avadh
Stranski-Krastanov strained islands undergo a shape anisotropy transition as they grow in size, finally evolving toward nanowires. This effect has been explained until now via simple energetic models...
Geometry induced charge separation on a helicoidal ribbon (2008)
Atanasov, Victor, Dandoloff, Rossen, Saxena, Avadh
We present an exact calculation of the effective geometry-induced quantum potential for a particle confined on a helicoidal ribbon. This potential leads to the appearance of localized states at the...
Compactons in PT-symmetric generalized Korteweg-de Vries Equations (2008)
Bender, Carl M., Cooper, Fred, Khare, Avinash, Mihaila, Bogdan, Saxena, Avadh
In an earlier paper Cooper, Shepard, and Sodano introduced a generalized KdV equation that can exhibit the kinds of compacton solitary waves that were first seen in equations studied by Rosenau and...
Sinitsyn, N. A., Saxena, Avadh
We develop a new interpretation of the geometric phase in evolution with a non-Hermitian real value Hamiltonian by relating it to the angle developed during the parallel transport along a closed...
Domain Wall and Periodic Solutions of Coupled phi6 and Coupled phi6-phi4 Models (2008)
We obtain several higher order periodic solutions of a Coupled phi6 model in terms of Lame polynomials of order one and two. These solutions are unusual in the sense that while they are the solutions...
Higher Order Periodic Solutions of Coupled phi4 Models (2008)
We obtain several higher order exact periodic solutions of (i) a coupled symmetric phi4 model in an external field, (ii) an asymmetric coupled phi4 model, (iii) an asymmetric-symmetric coupled phi4...
High-speed kinks in a generalized discrete $\phi^4$ model (2008)
Dmitriev, Sergey V., Khare, Avinash, Kevrekidis, Panayotis G., Saxena, Avadh, Hadzievski, Ljupco
We consider a generalized discrete $\phi^4$ model and demonstrate that it can support exact moving kink solutions in the form of tanh with an arbitrarily large velocity. The constructed exact moving...
Using Jacobi elliptic function addition formulas and summation identities we obtain several static and moving periodic soliton solutions of a classical anisotropic, discrete Heisenberg spin chain...
Khare, Avinash, Dmitriev, Sergey V., Saxena, Avadh
For a five-parameter discrete $\phi^4$ model, we derive various exact static solutions, including the staggered ones, in the form of the basic Jacobi elliptic functions $\sn$, $\cn$, and $\dn$, and...
Yang, Ping, Batista, Enrique R., Tretiak, Sergei, Saxena, Avadh, Martin, Richard L., Smith, D. L.
We investigate the role of intra-molecular conformational disorder and inter-molecular electronic interactions on the electronic structure of disorder clusters of poly-p-phenylene vinylene (PPV)...
Exact static solutions to a translationally invariant discrete $\phi^4$ model (2007)
Dmitriev, Sergey V., Kevrekidis, Panayotis G., Khare, Avinash, Saxena, Avadh
For a discrete, translationally-invariant $\phi^4$ model introduced by Barashenkov {\it et al.} [Phys. Rev. E {\bf 72}, 35602R (2005)], we provide the momentum conservation law and demonstrate how...
Khare, Avinash, Dmitriev, Sergey V., Saxena, Avadh
We obtain exact moving and stationary, spatially periodic and localized solutions of a generalized discrete nonlinear Schr\"odinger equation. More specifically, we find two different moving periodic...
Domain Wall and Periodic Solutions of Coupled Asymmetric Double Well Models (2006)
Coupled asymmetric double well ($a\phi^2-b\phi^3+c\phi^4$) one-dimensional potentials arise in the context of first order phase transitions both in condensed matter physics and field theory. Here we...
Domain Wall and Periodic Solutions of a Coupled phi6 Model (2006)
Coupled triple well (phi6) one-dimensional potentials occur in both condensed matter physics and field theory. Here we provide a set of exact periodic solutions in terms of elliptic functions (domain...
Comparative Study of Different Discretizations of the $\phi^4$ Model (2006)
Roy, Ishani, Dmitriev, Sergey V., Kevrekidis, Panayotis G., Saxena, Avadh
We examine various recently proposed discretizations of the well-known $\phi^4$ field theory. We compare and contrast the properties of their fundamental solutions including the nature of their...
Domain Wall and Periodic Solutions of Coupled phi4 Models in an External Field (2006)
Coupled double well (phi4) one-dimensional potentials abound in both condensed matter physics and field theory. Here we provide an exhaustive set of exact periodic solutions of a coupled $\phi^4$...
Cooper, Fred, Khare, Avinash, Saxena, Avadh
We derive a general theorem relating the energy and momentum with the velocity of any solitary wave solution of the generalized KdV equation in $N$-dimensions that follows from an action principle....
Discrete Nonlinear Schrodinger Equations with arbitrarily high order nonlinearities (2006)
Khare, Avinash, Rasmussen, Kim Ø., Salerno, Mario, Samuelsen, Mogens R., Saxena, Avadh
A class of discrete nonlinear Schrodinger equations with arbitrarily high order nonlinearities is introduced. These equations are derived from the same Hamiltonian using different Poisson brackets...
Exact Elliptic Compactons in Generalized Korteweg-DeVries Equations (2005)
Cooper, Fred, Khare, Avinash, Saxena, Avadh
We derive a general theorem relating the energy, momentum and velocity of any solitary wave solution of the generalized KdV equation which enables us to relate the amplitude, width, and momentum to...
Statistical Mechanics of Lam\'e Solitons (2005)
Bena, Ioana, Khare, Avinash, Saxena, Avadh
We study the exact statistical mechanics of Lam\'e solitons using a transfer matrix method. This requires a knowledge of the first forbidden band of the corresponding Schr\"odinger equation with the...
Scrymgeour, David A, Gopalan, Venkatraman, Itagi, Amit, Saxena, Avadh, Swart, Pieter J
A phenomenological treatment of domain walls based on the Ginzburg-Landau-Devonshire theory is developed for uniaxial, trigonal ferroelectrics lithium niobate and lithium tantalate. The contributions...
Exact solitary wave solutions for a discrete $\lambda \phi^4$ field theory in 1+1 dimensions (2005)
Cooper, Fred, Khare, Avinash, Mihaila, Bogdan, Saxena, Avadh
We have found exact, periodic, time-dependent solitary wave solutions of a discrete $\phi^4$ field theory model. For finite lattices, depending on whether one is considering a repulsive or attractive...
Domain Size Dependence of Piezoelectric Properties of Ferroelectrics (2004)
Ahluwalia, Rajeev, Lookman, Turab, Saxena, Avadh, Cao, Wenwu
The domain size dependence of piezoelectric properties of ferroelectrics is investigated using a continuum Ginzburg-Landau model that incorporates the long-range elastic and electrostatic...
Spatial Structures in a Generalized Ginzburg-Landau Free Energy (2004)
Farid, Abdel-Khalek, Yu, Yonggang, Saxena, Avadh, Kumar, Pradeep
Searching for characteristic signatures of a higher order phase transition (specifically of order three or four), we have calculated the spatial profiles and the energies of a spatially varying order...
Spherical Vesicles Distorted by a Grafted Latex Bead: An Exact Solution (2004)
We present an exact solution to the problem of the global shape description of a spherical vesicle distorted by a grafted latex bead. This solution is derived by treating the nonlinearity in bending...
Semiclassical kinetic theory of electron spin relaxation in semiconductors (2004)
Bronold, Franz X., Saxena, Avadh, Smith, Darryl L.
We develop a semiclassical kinetic theory for electron spin relaxation in semiconductors. Our approach accounts for elastic as well as inelastic scattering and treats Elliott-Yafet and...
Soliton Lattice and Single Soliton Solutions of the Associated Lam\'e and Lam\'e Potentials (2004)
Bena, Ioana, Khare, Avinash, Saxena, Avadh
We obtain the exact nontopological soliton lattice solutions of the Associated Lam\'e equation in different parameter regimes and compute the corresponding energy for each of these solutions. We show...
Viscoelastic Properties of Dynamically Asymmetric Binary Fluids Under Shear Flow (2003)
Dwivedi, Vinay, Ahluwalia, Rajeev, Lookman, Turab, Saxena, Avadh
We study theoretically the viscoelastic properties of sheared binary fluids that have strong dynamical asymmetry between the two components. The dynamical asymmetry arises due to asymmetry between...
Landau Theory For Shape Memory Polycrystals (2003)
Ahluwalia, Rajeev, Lookman, Turab, Saxena, Avadh, Albers, Robert C
We propose a Ginzburg-Landau theory for the elastic properties of shape memory polycrystals. A single crystal elastic free energy for a system that undergoes a square-to-rectangle transformation is...
Electromechanical Properties of Multi-Domain Ferroelectrics (2003)
Ahluwalia, Rajeev, Lookman, Turab, Saxena, Avadh, Cao, Wenwu
We study theoretically the influence of the underlying domain microstructure on the electromechanical properties of ferroelectrics. Our calculations are based on a continuum approach that...
Self-Dual Bending Theory for Vesicles (2002)
Benoit, Jerome, Von Hauff, Elizabeth, Saxena, Avadh
We present a self-dual bending theory that may enable a better understanding of highly nonlinear global behavior observed in biological vesicles. Adopting this topological approach for spherical...
Elastic Deformation of Polycrystals (2002)
Ahluwalia, Rajeev, Lookman, Turab, Saxena, Avadh
We propose a framework to model elastic properties of polycrystals by coupling crystal orientational degrees of freedom with elastic strains. Our model encodes crystal symmetries and takes into...
Magnetic-field dependence of electron spin relaxation in n-type semiconductors (2002)
Bronold, Franz X., Martin, Ivar, Saxena, Avadh, Smith, Darryl L.
We present a theoretical investigation of the magnetic field dependence of the longitudinal ($T_1$) and transverse ($T_2$) spin relaxation times of conduction band electrons in n-type III-V...
Glassy behavior in systems with Kac-type step-function interaction (2002)
Loh, Kok-Kiong, Kawasaki, Kyozi, Bishop, Alan R., Lookman, Turab, Saxena, Avadh, Schmalian, Jörg, ...
We study a system with a weak, long-range repulsive Kac-type step-function interaction within the framework of a replicated effective $\phi^4$-theory. The occurrence of extensive configurational...
Interaction of a Discrete Breather with a Lattice Junction (2002)
Bena, Ioana, Saxena, Avadh, Sancho, Jose Maria
We study the scattering of a moving discrete breather (DB) on a junction in a Fermi-Pasta-Ulam (FPU) chain consisting of two segments with different masses of the particles. We consider four distinct...
Phase transition induced hydrodynamic instability and Langmuir-Blodgett Deposition (2001)
Loh, Kok-Kiong, Saxena, Avadh, Lookman, Turab, Parikh, Atul N.
We propose a model to understand periodic oscillations relevant to the origin of mesoscopic channels formed during a Langmuir-Blodgett deposition observed in recent experiments \{M. Gleiche, L.F....
Bogomol'nyi Decomposition for Vesicles of Arbitrary Genus (2001)
Benoit, Jerome, Saxena, Avadh, Lookman, Turab
We apply the Bogomol'nyi technique, which is usually invoked in the study of solitons or models with topological invariants, to the case of elastic energy of vesicles. We show that spontaneous...
Heisenberg Spins on a Cylinder Section (1999)
Benoit, Jerome, Dandoloff, Rossen, Saxena, Avadh
Classical Heisenberg spins in the continuum limit (i.e. the nonlinear sigma-model) are studied on an elastic cylinder section with homogeneous boundary conditions. The latter may serve as a physical...
Statistical Mechanics of Double sinh-Gordon Kinks (1998)
Habib, Salman, Khare, Avinash, Saxena, Avadh
We study the classical thermodynamics of the double sinh-Gordon (DSHG) theory in 1+1 dimensions. This model theory has a double well potential, thus allowing for the existence of kinks and antikinks....
Exact Thermodynamics of the Double sinh-Gordon Theory in 1+1-Dimensions (1997)
Khare, Avinash, Habib, Salman, Saxena, Avadh
We study the classical thermodynamics of a 1+1-dimensional double-well sinh-Gordon theory. Remarkably, the Schrodinger-like equation resulting from the transfer integral method is quasi-exactly...
Statistical Mechanics of Nonlinear Coherent Structures: Kinks in the Phi^6 Model (1995)
We study the thermodynamics of kinks in the Phi^6 model using a Langevin code implemented on a massively parallel computer. This code can be used to study first order dynamical phase transitions...
Cross-polarized excitons in carbon nanotubes
Kilina, Svetlana, Tretiak, Sergei, Doorn, Stephen K., Luo, Zhengtang, Papadimitrakopoulos, Fotios, Piryatinski, Andrei, ...
Polarization of low-lying excitonic bands in finite-size semiconducting single-walled carbon nanotubes (SWNTs) is studied by using quantum-chemical methodologies. Our calculations elucidate...