Improving the full update and probing frustrated J₁-J₂ spin-1/2 model on a square lattice

The optimization of infinite projected entangled-pair state (iPEPS) ansatz
represents the main challenge in obtaining accurate ground states of lattice
models. In this work, we propose a simple modification of the full-update
algorithm [1] and benchmark it on a frustrated J₁-J₂ spin-1/2 Heisenberg
model on a square lattice. Using an improved full-update, we obtain
extremely accurate ground-state energies but, most importantly, also
values of the magnetization that are comparable with previous results
from more complex variational optimization [2,3]. Moreover, we show
that the recent scaling technique based on the correlation length [4,5]
leads to a considerable improvement in analysis of the phase diagram.

[1] H. N. Phien, J. A. Bengua, H. D. Tuan, P. Corboz, R. Orus, Phys. Rev. B 92, 035142 (2015)
[2] P. Corboz, Phys. Rev. B 94, 035133 (2016)
[3] L. Vanderstraeten, J. Haegeman, P. Corboz, F. Verstraete, Phys. Rev. B 94, 155123 (2016)
[4] P. Corboz, P. Czarnik, G. Kapteijns, L. Tagliacozzo, Phys. Rev. X 8, 031031 (2018)
[5] M. Rader, A. M. Läuchli, Phys. Rev. X 8, 031030 (2018)