Applying the functional Schroedinger picture to the Holstein-Primakoff boson theory, we obtain a dispersion energy relation for an antiferromagnetic spin polaron or magnon in two-dimensional systems of strongly correlated electrons. We show that our magnon ground-state wave function is equivalent to that of a retraceable path approximation by Reiter in the long-wavelength limit. Further, we demonstrate that the derived dispersion relation of a quasiparticle leads to the self-consistent Born approximation of the Green's function approach only in the large Heisenberg coupling J limit, showing that this new approach is general enough to contain more physical information than the Green's function approach in dealing with the antiferromagnetic spin polaron of interest.
Keyword
Functional Schroedinger picture theory; Holstein-Primakoff boson theory; Dispersion energy relation; Antiferromagnetic spin polaron; Two-dimensional systems of strongly correlated electrons