Fig. 7: Scalability of the CPD backflow ansatz.
From: Simple Fermionic backflow states via a systematically improvable tensor decomposition
Mean VMC step runtime for the CPD backflow ansatz as a function of the number of atoms in a hydrogen chain with fixed inter-atomic distances (1.68 Å) in a STO-6G basis. The support dimension is M = 1 and the sample size is NS = 128. The blue points are obtained with the full Hamiltonian, while the green and orange points are obtained with the local energy evaluated with a Hamiltonian pruned with a threshold of 10−9 and 10−5 Eh. The dashed lines show the observed scaling for the largest system sizes. Average runtimes are obtained over 50 iterations, with error bars represented by the standard error across these runtimes.
