Training Quantum Evolutions Using Sublogical Controls

A method comprising:

• programming, by a classical processor, a control pulse into a digital to analog converter (DAC) that operates on one or more multi-level quantum subsystems included in a quantum system, wherein control parameters of the DAC comprise physical control parameters and form a variational ansatz;
• measuring, by quantum hardware and during application of the control pulse by the DAC to the quantum system, an action of the DAC on the quantum system;
• comparing, by the classical processor, the measured action to a predefined intended action of the control pulse to determine whether the measured action differs to the predefined intended action;
• and
• in response to determining that the measured action differs to the predefined intended action, adjusting, by the classical processor, the control parameters of the DAC to calibrate, within the variational ansatz, the action of the DAC on the quantum system.

An apparatus comprising:

• quantum hardware comprising:
• a quantum system comprising one or more multi-level quantum subsystems;
• and
• at least one digital to analog converter (DAC) that operates on the multi-level quantum subsystems, wherein one or more control parameters of the DAC comprise physical control parameters and form a variational ansatz;
• and
• a classical processor configured to operate the quantum hardware;
• wherein the apparatus is configured to perform operations comprising:
• programming a control pulse into the at least one DAC;
• measuring, during application of the control pulse by the DAC to the quantum system, an action of the DAC on the quantum system;
• comparing the measured action to a predefined intended action of the control pulse to determine whether the measured action differs to the predefined intended action;
• and
• in response to determining that the measured action differs to the predefined intended action, adjusting the control parameters of the DAC to calibrate, within the variational ansatz, the action of the DAC on the quantum system.