Anneal Schedule Variations

Description

In the standard application of quantum annealing in D-Wave systems, qubits evolve according to a predetermined schedule, in which energy changes smoothly as a function of scaled time. As in previous releases, you can change the default duration using the annealing_time parameter when submitting a problem.

Some types of research, however, may benefit from more fine-grained adjustments to the default anneal schedule. To provide this level of control, anneal schedule features enable you to change the shape of the energy waveform by providing points at which to pause or quench (i.e., abruptly terminate) the anneal process; see Figure 82. This level of control helps investigate what is happening partway through the annealing process.

_images/annealing_trajectories.png

Fig. 18 Annealing schedule variations.

Unlike the anneal offsets feature—which allows you to control the annealing path of individual qubits separately—anneal schedule changes apply to all qubits in the working graph.

Release Introduced

Release 2.11

Properties and Parameters

User parameter:

  • anneal_schedule—Parameter that enables variations on the standard global anneal schedule.

    An anneal schedule variation is defined by a series of pairs of floating-point numbers identifying points in the schedule at which to change slope. The first element in the pair is time \(t\) in microseconds; the second, normalized persistent current \(s\) in the range [0,1]. The resulting schedule is the piecewise-linear curve that connects the provided points.

Solver properties (may vary by QPU):

  • max_anneal_schedule_points—Property that shows the maximum number of points at which the anneal schedule (waveform) can be changed for the solver.

See Also