FermionBasis(n_sites; sites=(-1, 1))

Construct a binary fermion basis for a chain of fermions with n_sites in form of an interator. The default field is (-1, 1) which can be optionally changed by specifying the keyword argument states as a Tuple. No allocations are made during construction. The basis can be materialized using collect (not recommended for long chains).

The quantum XY model projected to spinless fermions with periodic boundary conditions (PBC). The sites consist of the elements from set {-1, 1}, where -1 represents no fermion and 1 represents a fermion at that site.

The Ising model, i.e. the XY model with γ=1, projected to spinless fermions with PBC.

The XX model, also known as the isotropic (γ=0) XY model, projected to spinless fermions with PBC.

Returns the correlation matrix of the XY chain.

Returns the probability matrix of the XY chain.