Fig. 1: Numerical methods and strategy.
From: Entanglement in the quantum phases of an unfrustrated Rydberg atom array
a A schematic representation of Γ-point DMRG. A single infinite bulk configuration is given by periodic images of the central supercell configuration. The wavefunction coefficient for this infinite configuration is given by the contraction of a snake MPS, which is defined only within a single supercell. b By widely varying the size of the supercell, Γ-point DMRG obtains many different ground states. Identifying all accessible supercells which give the same ground state order (shown with identically colored points), we can ensure that all competing low-energy states are well converged w.r.t. finite size effects, and thus properly identify the true ground state (inset shows ground-state order (dark green) converged w.r.t. supercell size, separated from other low-energy orders by 10−4 energy units). c A PEPS wavefunction ansatz with bond dimension D for a finite system. Each tensor is a different color because they can all be unique. d A simplified diagrammatic representation of the long-range Hamiltonian construction for PEPS in ref. 32. All terms in the Hamiltonian are accounted for by a sum of Lx comb tensor network operators. Tensors of the same color are identical.
