Spinless fermion model

The purpose of these notes is to show how some strongly correlated electron models like the one-band Hubbard model with infinite electron repulsion on rectangular and triangular lattices can be described in terms of spinless fermions and the operators of cyclic spin permutations. We will consider in detail the... 

For Jz = 0, as stated above, H is equivalent to a noninteracting gas of spinless fermions, which for low energy phenomena is equivalent to a noninteracting Luttinger model. 

Del Campo et al. [89] have also generalized the model for a Tonks-Girardeau gas of N bosons with strongly repulsive contact interactions as well as spinless fermions with strongly attractive contact interactions and studied the long-time asymptotics and some new effects in the decay of these systems. 

The interband and vibronic contributions to the infrared properties of the model system have been calculated in the adiabatic, linear-response approximation. Two possible schemes for the occupation of the band states by a number of electrons or holes Np = N/2 (corresponding to half a carrier per molecule) have been considered (i) the case of regular fermion particles with spin, where the lower band only is half filled, (ii) that of spinless fermions, with the lower band completely full. Although no electron correlation term is explicitly included in the Hamiltonian, the latter case represents the situation that is attained, when the on-site correlation of an Hubbard model is U t. 

---