Distasio, M and Ercolessi, E and Morandi, G and RIGHI R, R and Tagliacozzo, A and Zucchelli, GP (1994) Effective action and adiabatic expansions for the 1-D and 2-D hubbard models at half-filling. In: International journal of modern physics B, 8 (10). 1391 -1416 .Full text not available from this repository.
We analyze here the occurrence of antiferromagnetic (AFM) correlations in the half-filled Hubbard model in one and two space dimensions using a natural fermionic representation of the model and a newly proposed way of implementing the half-filling constraint. We find that our way of implementing the constraint is capable of enforcing it exactly already at the lowest levels of approximation. We discuss how to develop a systematic adiabatic expansion for the model and how Berry's phase contributions arise quite naturally from the adiabatic expansion. At low temperatures and in the continuum limit the model gets mapped onto an O(3) nonlinear sigma model (NLsigma). A topological, Wess-Zumino term is present in the effective action of the ID NLsigma as expected, while no topological terms are present in 2D. Some specific difficulties that arise in connection with the implementation of an adiabatic expansion scheme within a thermodynamic context are also discussed, and we hint at possible solutions.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to World scientific publishing company.|
|Department/Centre:||Division of Physical & Mathematical Sciences > Centre for Theoretical Studies|
|Date Deposited:||01 Jun 2011 06:02|
|Last Modified:||11 Jan 2013 10:56|
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