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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 5 Issue 3 (1998) pp 605-611
Flow equations for band-matrices
A. Mielke (a)
Institut für Theoretische Physik, Ruprecht-Karls-Universität, Philosophenweg 19, 69120 Heidelberg, Germany
Received: 2 February 1998 / Accepted: 17 March 1998
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.
PACS. 03.65.-w Quantum mechanics - 02.70.Hm Spectral methods - 21.60.-n Nuclear-structure models and methods
(a) email: mielke@tphys.uni-heidelberg.de
Article in PDF format (277 KB)
Online publication: October 26, 1998
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