نتایج جستجو برای: hamiltonian model

تعداد نتایج: 2128187  

سیاوش آزاکوف, , نادر حیدری, ,

  We review various ways to express the partition function of the single-band Hubard model as a path integral. The emphasis is made on the derivation of the action in the integrand of the path integral and the results obtained from this approach are discussed only briefly.   Since the single-band Hubbard model is a pure fermionic model on the lattice and its Hamiltonian is a polynomial in creat...

Journal: :journal of computational & applied research in mechanical engineering (jcarme) 2012
chandan kumar vikas rastogi rastogi

this work deals with effects of asymmetric stiffness on the dynamic behaviour of the rotor system. the analysis is presented through an extended lagrangian hamiltonian mechanics on the asymmetric rotor system, where symmetries are broken in terms of the rotor stiffness. the complete dynamics of asymmetries of rotor system is investigated with a case study. in this work, a mathematical model is ...

Journal: :فیزیک کوانتومی 0

in this paper, lagrangian and equations describing one-dimensional anisotropic non-heisenberg model are studied. in this study we used the generalized coherent states in real parametrizations and the feynman path integral for these states in su(3) group. these equations describe nonlinear dynamics of non-heisenberg ferromagnetic chain completely. solutions of these equations are magnetic solito...

2009
Emanuele Tassi Cristel Chandre Philip Morrison E. Tassi C. Chandre P. J. Morrison

When dissipative terms are dropped, all of the important models of plasma physics are described by partial differential equations that possess Hamiltonian form in terms of noncanonical Poisson brackets. For example, this is the case for ideal magnetohydrodynamics, the Vlasov–Maxwell equations, and other systems see Refs. 7–9 for review . Among these, there exist several reduced fluid models who...

2007
Onno Bokhove

A two-layer Hamiltonian toy model consisting of two isentropic stratospheric layers is simplified using perturbation analysis while preserving the Hamiltonian structure. These two layers are neutrally and stably stratified. The first approximation applies when the Froude number of the upper isentropic layer is small, such that the upper surface is approximately rigid, and this upper layer is mu...

1999
A. Stern

The Hamiltonian formalism offers a natural framework for discussing the notion of Poisson Lie T-duality. This is because the duality is inherent in the Poisson structures alone and exists regardless of the choice of Hamiltonian. Thus one can pose alternative dynamical systems possessing nonabelian T-duality. As an example, we find a dual Hamiltonian formulation of the O(3) nonlinear σ-model. In...

Journal: :The Journal of chemical physics 2014
Alexander A Rusakov Jordan J Phillips Dominika Zgid

Embedding calculations that find approximate solutions to the Schrödinger equation for large molecules and realistic solids are performed commonly in a three step procedure involving (i) construction of a model system with effective interactions approximating the low energy physics of the initial realistic system, (ii) mapping the model system onto an impurity Hamiltonian, and (iii) solving the...

2008
J. CRESSON

As a model problem for the study of chaotic Hamiltonian systems, we look for the effects of a long-tail distribution of recurrence times on a fixed Hamiltonian dynamics. We follow Stanislavsky’s approach of Hamiltonian formalism for fractional systems. We prove that his formalism can be retrieved from the fractional embedding theory. We deduce that the fractional Hamiltonian systems of Stanisla...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2009
Tetsuo Deguchi Pijush K Ghosh

We show that a Dicke-type non-Hermitian Hamiltonian admits entirely real spectra by mapping it to the "dressed Dicke model" through a similarity transformation. We find a positive-definite metric in the Hilbert space of the non-Hermitian Hamiltonian so that the time evolution is unitary and allows a consistent quantum description. We then show that this non-Hermitian Hamiltonian describing nond...

In this paper, the crystal field parameters (CFPs) have been calculated in the framework of the density functional theory using a novel theoretical approach proposed by Pavel Novák et al. and extracting the WANNIER functions from the Bloch eigenstates for the CeCl3 compound. Then, the calculated CFPs  have been used in an effective atomic-like Hamiltonian, including the crystal field, 4f-4f cor...

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