Electronic Resource
Springer
Journal of low temperature physics
99 (1995), S. 615-624
ISSN:
1573-7357
Keywords:
11.28.+d
;
75.10.Lp
;
15.30.Kz
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Functional integral methods provide a way to define mean-field theories and to systematically improve them. For the Hubbard model and similar strong-correlation problems, methods based in particular on the Hubbard-Stratonovich transformation have however been plagued by difficulties to formulate the problem in a spin-rotation invariant way. Here a formalism circumventing this problem by using a space- and time-dependent spin reference axis is discussed. This formulation is then used to suggest a possible alternative to Nagaoka ferromagnetism in the strongly correlated Hubbard model in the vicinity of half-filling. Finally, some aspects of single-particle spectra in a simplified model for a short-range ordered antiferromagnet are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00752352
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