Results 261 to 270 of about 304,578 (296)

Density-Matrix Expansion for an Effective Nuclear Hamiltonian

Physical Review C, 1972
An expansion for the nuclear wave-function density matrix in relative and c.m. coordinates is developed such that the leading term is the corresponding nuclear-matter density matrix at the local neutron and proton density. Truncation of all derivatives beyond second order yields an extremely simple form for the energy density which retains all the ...
Negele, W., Vautherin, D.
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Computing polarizabilities without a Hamiltonian matrix

Chemical Physics Letters, 2012
Abstract Using techniques of numerical linear algebra it is possible to calculate polarizabilities and hyperpolarizabilities without computing or storing a Hamiltonian matrix. This is done by exploiting the structure of the basis to evaluate matrix–vector products. The ideas are tested on a one dimensional Hubbard model.
Alexander Wlotzka, Tucker Carrington
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Density Matrix Theory for the BDS-Hamiltonian

International Journal of Theoretical Physics, 2001
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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$����$ scattering in a renormalized Hamiltonian matrix

2019
5 pages, 4 figures, presented by Mar\'ia G\'omez-Rocha at Light Cone 2019, 16-20 September 2016, Palaiseau ...
G��mez-Rocha, Mar��a, Arriola, Enrique Ruiz   +1 more
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WKB approximation for general matrix Hamiltonians

Physical Review D, 1981
We present a method of obtaining WKB-type solutions for generalized Schroedinger equations for which the Hamiltonian is an arbitrary matrix function of any number of pairs of canonical operators. Our solution reduces the problem to that of finding the matrix which diagonalizes the classical Hamiltonian and determining the scalar WKB wave functions for ...
James D. Bjorken, Harry S. Orbach
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Calculation of the Hamiltonian Matrix

2000
In most atomic and molecular calculations one uses the following Hamiltonian: $$\mathcal{H} = \sum\limits_{{i = 1}}^{N} {\left[ { - \frac{1}{2}\nabla _{i}^{2} - \sum\limits_{{\alpha = 1}}^{v} {\frac{{{{Z}_{\alpha }}}}{{{{r}_{{ia}}}}}} } \right] + \sum\limits_{{i < j}}^{N} {\frac{1}{{{{r}_{{ij}}}}} + \sum\limits_{{\alpha < \beta }}^{v} {\frac{{{{Z}_{
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Matrix elements of a spin-adapted reduced Hamiltonian

Physical Review A, 1986
A formalism based on the unitary- and symmetric-group approaches to configuration-interaction methods has been applied to an evaluation of matrix elements of a spin-adapted reduced Hamiltonian (SRH). It has been shown that there is a simple closed-form expression for the matrix elements of the SRH matrices.
, Karwowski, , Duch, , Valdemoro
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Hamiltonian Matrix and Reduced Density Matrix Construction with Nonlinear Wave Functions

The Journal of Physical Chemistry A, 2006
An efficient procedure to compute Hamiltonian matrix elements and reduced one- and two-particle density matrices for electronic wave functions using a new graphical-based nonlinear expansion form is presented. This method is based on spin eigenfunctions using the graphical unitary group approach (GUGA), and the wave function is expanded in a basis of ...
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The S matrix for absorptive Hamiltonians

Annals of Physics, 1985
Abstract The existence of a matrix S such that S S = 1 in the presence of absorption is demonstrated. In the limit of a hermitian Hamiltonian the unitarity condition SSdg = 1 is recovered. A dispersion relation for forward seattering is derived and the properties of the reactance matrices K and K are obtained.
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Renormalization of a Finite Matrix Hamiltonian

Journal of Mathematical Physics, 1969
We investigate the eigenvalues of a finite matrix Hamiltonian H = H0 + g0V, where H0 is diagonal with eigenvalues 1, 2, …, N, and where all the elements of V are equal to 1. We are interested in the case N → ∞. The radius of convergence of the perturbation series is (ln N)−1, but nevertheless the exact eigenvalues of H tend to well-defined limits when ...
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