Spin Permutation Formalism for Hubbard Model with Infinite Repulsion

CYCLIC SPIN PERMUTATION FORMALISM FOR HUBBARD MODEL WITH INFINITE REPULSION 

The Hubbard model with infinite electron repulsion represents restricted hopping in a space with no doubly occupied sites. For the iV-electron system on the lattice formed by L sites the model Hamiltonian has the form [27] 

Here 0(n1,n2,-, ) is a coordinate function that describes the distribution of N electrons over the L lattice sites n, labels the i-th singly occupied lattice site M is the z-projection of total spin of a lattice D is the dimensionality of the space spanned by the eigenvectors of (3) and T1,o 2. 7Af) is a function of spin variables cr , describing the spin configuration of the electrons 

In the case of nonlinear lattice topology, electron hops mix different spin configurations and the corresponding eigenvalue problem becomes much more complicated. A complete analytical solution of this problem is known only for some special cases (e.g. for the linear chain with periodic boundary conditions [22]). In the absence of exact results a reliable way to describe the properties of nonlinear systems is to perform a numerical study of the electron structure for finite lattice clusters. 

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