Time ordering, energy ordering, and factorization
نویسندگان
چکیده
منابع مشابه
Ordering Methods for Approximate Factorization Preconditioning
We investigate the ordering and ll-in strategies for approximate factorization preconditioning, focusing on automatic procedures to take care that a user friendly solver should converge equally fast whatever the original numbering of the unknowns. Considering the discrete PDE context, we pay particular attention to anisotropic problems for which factorizations without ll-in may behave poorly, w...
متن کاملar X iv : h ep - p h / 99 07 49 0 v 1 2 6 Ju l 1 99 9 Time Ordering , Energy Ordering , and Factorization
Relations between integrals of time-ordered product of operators, and their representation in terms of energy-ordered products are studied. Both can be decomposed into irreducible factors and these relations are discussed as well. The energy-ordered representation was invented to separate various infrared contributions in gauge theories. It is shown that the irreducible time-ordered expressions...
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We study a natural conjecture regarding ferromagnetic ordering of energy levels in the Heisenberg model which complements the Lieb-Mattis Theorem of 1962 for antiferromagnets: for ferromagnetic Heisenberg models the lowest energies in each subspace of fixed total spin are strictly ordered according to the total spin, with the lowest, i.e., the ground state, belonging to the maximal total spin s...
متن کاملTime ordering and counting statistics
The basic quantum mechanical relation between fluctuations of transported charge and current correlators is discussed. It is found that, as a rule, the correlators are to be time-ordered in an unusual way. Instances where the difference with the conventional ordering matters are illustrated by means of a simple scattering model. We apply the results to resolve a discrepancy concerning the third...
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Orbitals are invaluable in providing a model of bonding in molecules or between molecules and surfaces. Most present-day methods in computational chemistry begin by calculating the molecular orbitals of the system. To what extent have these mathematical objects analogues in the real world? To shed light on this intriguing question, we employ a photoemission tomography study on monolayers of 3,4...
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ژورنال
عنوان ژورنال: Journal of Mathematical Physics
سال: 2000
ISSN: 0022-2488,1089-7658
DOI: 10.1063/1.533356