1. Kato expansion in quantum canonical perturbation theory.
- Author
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Nikolaev, Andrey
- Subjects
- *
PERTURBATION theory , *ALGORITHMS , *HAMILTONIAN systems , *LIOUVILLE'S theorem , *OPERATOR theory , *MATHEMATICAL expansion , *QUANTUM theory - Abstract
This work establishes a connection between canonical perturbation series in quantum mechanics and a Kato expansion for the resolvent of the Liouville superoperator. Our approach leads to an explicit expression for a generator of a block-diagonalizing Dyson's ordered exponential in arbitrary perturbation order. Unitary intertwining of perturbed and unperturbed averaging superprojectors allows for a description of ambiguities in the generator and block-diagonalized Hamiltonian. We compare the efficiency of the corresponding computational algorithm with the efficiencies of the Van Vleck and Magnus methods for high perturbative orders. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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