Reverse quantum annealing with dissipation*

Reverse annealing is a variant of quantum annealing where one initializes the system in a random classical state. The transverse field is first increased and then decreased at an inversion point, to find a better output state than the initial state of a given optimization problem. The procedure may be iterated with the last output state as the new input state.

[1] studied the unitary dynamics of reverse annealing of the fully-connected ferromagnetic p-spin model. Here we investigate the performance of reverse annealing for the p-spin model in a low-temperature open system setting. We study a system of qubits with collective and individual system-bath interaction models. We simulate the Markovian dynamics over a range of initial states and inversion points, and show that the relaxation mechanism gives an overall enhancement of performance over the closed-system setting. We also analyze the case of pausing at the inversion point, and show that prolonged relaxation near the avoided crossing can allow us to find the correct ground state solution with near certainty.

[1] Y. Yamashiro, M. Ohkuwa, H. Nishimori, D.A. Lidar, arXiv:1906.10889 (Phys. Rev. A, in press).