lattice_propogation

Script which uses the FCIQMC algorithm without annihilation to propogate positive and negative psips using Hamiltonians defined in both Hartree product and Slater determinant bases for two spinless fermions on a \(4\times4\) lattice with periodic boundary conditions. The Hamiltonian operator is:

\[\begin{split}H = - \sum_{<ij>} t \left( c^\dagger_j c_i + c^\dagger_i c_j - u n_i n_j \right).\end{split}\]

This is an example where the evolution of an FCIQMC calculation is step-by-step identical in both first- and second-quantized basis sets.

This is an independent implementation of work originally performed by Michael Kolodrubetz and Bryan Clark (Princeton).