Extended Data Fig. 8: Evolution time required to converge from two distant initial states in an 1,800-spin lattice.
From: Observation of topological phenomena in a programmable lattice of 1,800 qubits
a–c, We initialize the quantum simulation (QA) and the classical Monte Carlo simulation (QMC) with single-spin updates (that is, no cluster updates) in two classical ground states, shown for L = 6 with pink and blue representing up and down Ising spins, respectively. One is a clock state (a) with order parameter \(m=2/\sqrt{3}\). The other is a striped state (b), which has m = 0 and is far from other classical ground states in Hamming distance. As these initial states are evolved in either QA or QMC for increasing evolution times, m converges towards a steady state (c) regardless of initial condition. The uptick of m for long QA evolution may be a signature of on-chip cooling during evolution. d, The time required to converge m for the two initial conditions to within 0.3 of each other increases with s, as thermal and quantum fluctuations drop and dynamics slow. This indicates that QMC simulates only the equilibrium statistics of quantum evolution—not the dynamics.
