Abstract
A general quantum many-body theory in configuration space is developed by extending the traditional coupled-cluster method (CCM) to a variational formalism. Two independent sets (destruction and creation sets) of distribution functions are introduced to evaluate the Hamiltonian expectation. An algebraic technique for calculating these distribution functions via two self-consistent set of equations is given. By comparing with the traditional CCM and with Arponen's extension, it is shown that the former is equivalent to a linear approximation to one set of distribution functions and the latter is equivalent to a (generalized) random-phase approximation to it. In addition to these two approximations, other higher-order approximation schemes within the formalism are also discussed. As a demonstration, we apply this technique to a quantum antiferromagnetic spin model.
Original language | English |
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Article number | 184427 |
Pages (from-to) | 1844271-1844276 |
Number of pages | 5 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 66 |
Issue number | 18 |
DOIs | |
Publication status | Published - 1 Nov 2002 |