Figure 4: Simulated quantum annealing in the closed system.
From: Quantum annealing for the number-partitioning problem using a tunable spin glass of ions
Unitary time evolution of the full system (N=6) for different laser detunings δ between the fourth and fifth resonance. Thick lines show the result of the exact evolution, while the thin lines have been obtained from the semi-classical approximation. In all cases, the desired pattern (+++−−−) can be read out after sufficiently long annealing times. While in a,b we operate at the onset of glassiness, δ=2π × 239 kHz, c considers a ferromagnetic instance, δ=2π × 143 kHz. The annealing protocol in a is defined by Bmax=50Jrms and 
ms. In b the same instance is solved with higher fidelity by choosing Bmax=80 Jrms and 
ms. Fast annealing, with Bmax=50 Jrms and 
ms, is possible in the ferromagnetic instance in (c). In all simulations, we have chosen Ω=2π × 50 kHz, ωrecoil=2π × 15 kHz, and 
kHz.
