Flow equations for band--matrices
Quantum Physics
2009-10-31 v1 Statistical Mechanics
Mathematical Physics
math.MP
Nuclear Theory
Abstract
Continuous unitary transformations can be used to diagonalize or approximately diagonalize a given Hamiltonian. In the last four years, this method has been applied to a variety of models of condensed matter physics and field theory. With a new generator for the continuous unitary transformation proposed in this paper one can avoid some of the problems of former applications. General properties of the new generator are derived. It turns out that the new generator is especially useful for Hamiltonians with a banded structure. Two examples, the Lipkin model, and the spin--boson model are discussed in detail.
Keywords
Cite
@article{arxiv.quant-ph/9803040,
title = {Flow equations for band--matrices},
author = {Andreas Mielke},
journal= {arXiv preprint arXiv:quant-ph/9803040},
year = {2009}
}
Comments
12 pages, one eps-figure, uses epsfig.sty. Accepted for publication in European Physical Journal