Unlocking coherent reverse annealing on a D-Wave Advantage2 quantum processor

In reverse quantum annealing, a system of coupled qubits is initialized in an eigenstate of the computational basis of the transverse field Ising Hamiltonian. The initially weak global transverse field is then ramped up to a finite amplitude, and the system evolves under these conditions for a specified duration. Finally, the transverse field is reduced to its initial value to read out the final state. Reverse annealing provides important benefits over forward quantum annealing. In the context of quantum optimization, the option to seed the quantum annealer in a classical state allows for iterative refinement of previously found solutions via local search and may, under appropriate conditions, allow for finding global minima substantially faster than forward annealing. In the realm of quantum simulation, it allows for studying the Ising dynamics of specified initial states. So far, reverse annealing on D-Wave’s quantum processors has been largely limited to studies of open system dynamics. This presentation will describe a novel fast reverse annealing protocol which enables reverse annealing in the coherent regime on a D-Wave Advantage2™ quantum processor. Results from exploratory experiments with the novel annealing protocol will be presented to illustrate the transition from incoherent to coherent dynamics and to showcase the possibility of repeatedly accessing the coherent quantum annealing regime.