| Among the electronic Hamiltonians relevant for interacting systems the Hubbard model is considered as the one that contains the essential ingredients for understanding the physics of correlated electrons. Here, the relevant physics is encoded in the symmetries and in the Hubbard model which are represented by the charge U(1) gauge and spin rotational SU(2) groups relevant for the occurrence of the superconducting and magnetic orderings. In the present work we develop a spin-charge unifying description for interacting electrons in the Hubbard model that preserves the spin-rotational symmetry of system. The collective variables for charge and spin are isolated in the form of the space-time fluctuating U(1) phase field and rotating spin quantization axis governed by the SU(2) symmetry, respectively. As a result interacting electrons appear as a composite objects consisting of bare fermions with attached U(1) and SU(2) gauge fields. We examine the possibility whether that the existence of the emergent gauge fields may be responsible for the electron pairing similar to the action of phonons - as in the BCS theory. The resulting possible pairing scenarios are discussed. |
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