Scaling and diabatic effects in quantum annealing with a D-Wave device
Rönkkö, Jami M.
Åström, Jan A.
Sandvik, Anders W.
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Citation (published version)Phillip Weinberg, Marek Tylutki, Jami M Rönkkö, Jan Westerholm, Jan A Åström, Pekka Manninen, Päivi Törmä, Anders W Sandvik. 2020. "Scaling and Diabatic Effects in Quantum Annealing with a D-Wave Device.." Phys Rev Lett, Volume 124, Issue 9, pp. 090502 - ?. https://doi.org/10.1103/PhysRevLett.124.090502
We discuss quantum annealing of the two-dimensional transverse-field Ising model on a D-Wave device, encoded on L×L lattices with L≤32. Analyzing the residual energy and deviation from maximal magnetization in the final classical state, we find an optimal L dependent annealing rate v for which the two quantities are minimized. The results are well described by a phenomenological model with two powers of v and L-dependent prefactors to describe the competing effects of reduced quantum fluctuations (for which we see evidence of the Kibble-Zurek mechanism) and increasing noise impact when v is lowered. The same scaling form also describes results of numerical solutions of a transverse-field Ising model with the spins coupled to noise sources. We explain why the optimal annealing time is much longer than the coherence time of the individual qubits.