Theoretical Approach to Strongly Correlated Systems Based on the U(1) and SU(2) Symmetry Groups

• Authors: T. Kopeć
• Languages of publication: EN

Abstracts

EN

The spin-rotationally invariant SU(2)×U(1) approach to the Hubbard model is extended to accommodate the charge degrees of freedom. Both U(1) and SU(2) gauge transformation are used to factorize the charge and spin contribution to the original electron operator in terms of the emergent gauge fields. By tracing out gauge bosons the form of paired states is established and the role of antiferromagnetic correlations is explicated. We argue that in strongly correlated electron system collective instanton excitations of the phase field (dual to the charge) arise with a great degree of stability, governed by gauge flux changes by an integer multiple of 2π. Furthermore, it is shown that U(1) and SU(2) gauge fields play a similar role as phonons in the BCS theory: they act as the the "glue" for fermion pairing.

Keywords

EN

74.20.-z; 74.20.Fg; 71.10.Pm

Discipline

• 74.20.Fg: BCS theory and its development
• 74.20.-z: Theories and models of superconducting state
• 71.10.Pm: Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.)(for anyon mechanism in superconductors, see 74.20.Mn)

• Journal: Acta Physica Polonica A
• Year: 2012
• Volume: 121
• Issue: 4
• Pages: 738-743

Dates

published

2012-04

Contributors

author

T. Kopeć

• Institute for Low Temperature and Structure Research, Polish Academy of Sciences , POB 1410, 50-950 Wroclaw 2, Poland

References

• 1. L.D. Landau, Sov. Phys. JETP 3, 920 (1957)
• 2. J. Hubbard, Proc. R. Soc. London, Ser. A 276, 238 (1963); M.C. Gutzwiller, Phys. Rev. Lett. 10, 159 (1963); J. Kanamori, Prog. Theor. Phys. 30, 275 (1963)
• 3. K.A. Chao, J. Spalek, A.M. Oleś, J. Phys. C: Solid Stete Phys. 10, L271 (1977)
• 4. Y. Aharonov, D. Bohm, Phys. Rev. 115, 485 (1959)
• 5. V.N. Popov, Functional integrals and collective excitations, Cambridge Univesity Press, 1987
• 6. L.S. Schulman, Techniques and Applications of Path Integration, Wiley, New York 1981
• 7. H.J. Schulz, Phys. Rev. Lett. 65, 2462 (1990)
• 8. N.F. Mott, Metal-Insulator Transitions, Taylor&Francis, London 1990
• 9. T.K. Kopeć, Phys. Rev. B 73, 104505 (2006)
• 10. G. Morandi, The Role of Topology in Classical and Quantum Physics, Springer-Verlag, 1992

Identifiers

DOI

10.12693/APhysPolA.121.738