Power of Pausing: Advancing Understanding of Thermalization in Experimental Quantum Annealers

This study investigates the impact of different annealing schedules on quantum annealing hardware, specifically using the D-Wave 2000Q system. The objective is to understand how the inclusion of a pause during the annealing process influences thermalization and the system dynamics. By experimenting with forward and reverse annealing techniques interspersed with strategic pauses, we provide evidence that pausing the system can significantly alter the probability distribution of outcomes. Results show that introducing a pause near the minimum gap can enhance the likelihood of reaching the ground state, improving success rates over an order of magnitude in complex problems involving up to 500 qubits. Furthermore, the outcomes closely resemble a classical Boltzmann distribution, albeit at a considerably elevated effective temperature. Larger problems demonstrate an increased tendency to thermalize toward this distribution, suggesting deeper insights into the thermal effects governing quantum devices. This research contributes to a better understanding of quantum annealers and their operational principles, crucial for advancing quantum computing technologies.