Revising the 1/N Expansion for the Slave-Boson Approach within the Functional Integral

  • E. Arrigoni
  • C. Castellani
  • R. Raimondi
  • G. C. Strinati
Part of the NATO ASI Series book series (NSSB, volume 343)


In recent years the slave-boson method1 has been applied to a large variety of strongly correlated problems including the Kondo impurity and lattice2, the Anderson Hamiltonian3, and the Hubbard model(s)4. The method, which maps the physical electron destruction operator c σ with spin σ into products of new fermions d σ and bosons b, has been usually treated within a functional integral representation of the partition function since this representation suitably enforces the constraints of the theory and allows for a large-N expansion, which is free from infrared divergences in the so-called radial gauge5,6. Despite the large literature in the field, it appears that few analises have been carried out on the quantitative reliability of the method. This point was addressed by Zhang, Jain, and Emery7 for a two-level single-site problem. They concluded that the slave boson approach and the large N expansion were inadequate to reproduce the known exact results for this simple model. In Ref.[7], as in all previous literature, it was assumed that the continuum imaginary time limit (which is implicit in any path integral definition) can be safely taken at the outset in the effective action.


Exact Result Continuum Limit Hubbard Model European Economic Community Boson Field 
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Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • E. Arrigoni
    • 1
  • C. Castellani
    • 2
  • R. Raimondi
    • 2
  • G. C. Strinati
    • 1
    • 2
  1. 1.Scuola Normale SuperiorePisaItaly
  2. 2.Dipartimento di FisicaUniversità “La Sapienza”RomaItaly

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