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Q: Fachverband Quantenoptik und Photonik

Q 37: Poster III

Q 37.9: Poster

Wednesday, March 13, 2024, 17:00–19:00, Tent B

Speeding up Quantum Annealing with coupling to meter — •Mykolas Sveistrys¹, Giovanna Morigi², and Christiane P. Koch¹ — ¹Fachbereich Physik and Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany — ²Theoretische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany

Quantum annealing is a quantum computing paradigm with great promise, but also many doubts whether it can produce speedups over classical calculations. To speed up quantum annealing calculations, we introduce a (potentially) dissipative protocol that involves a meter qubit coupled to the qubit array (the system) encoding the annealing problem. The coupling is designed to commute with the system Hamiltonian at all times. Depending on the state of the meter qubit, two mechanisms emerge that result in enhanced adiabaticity and, therefore, a faster time-to-solution: dephasing of the system in its instantaneous eigenbasis, and an effective rescaling of the system's energy levels. We first analyse analytically the conditions where each mechanism dominates, finding that under some circumstances, one should optimize for maximal energy rescaling at the cost of zero dephasing. We then numerically demonstrate the speedup such a protocol yields. We show a 3.6x speedup in time-to-solution on a small-scale instance of the Minimum Weighted Vertex Cover Problem, and a 28% speedup in time-to-solution, seemingly without any dependence on problem size, on a larger benchmark of random Ising models.

Keywords: Quantum Annealing; Shortcuts To Adiabaticity; Quantum Algorithms; Engineered Dissipation; Adiabatic Quantum Computing