Abstract: A method is presented for controlling a spin system in an external magnetic field. The method includes sending a first pulse to a resonator over a first period. The resonator generates a magnetic field in response to receiving the first pulse. Moreover, the resonator applies the magnetic field to the spin system and the first pulse maintains the magnetic field in a transient state during the first period. The method also includes sending a second pulse to the resonator over a second period immediately following the first period. The resonator alters a magnitude of the magnetic field to zero in response to receiving the second pulse. Other methods are presented for controlling a spin system in an external magnetic field, including systems for controlling a spin system in an external field.

Abstract: In a general aspect, a sample holder has multiple sample containers. In some instances, the sample holder can be received into a resonator package in a primary magnetic field of a magnetic resonance system. The resonator package includes a resonator configured to interact with a sample in a sample region. The sample holder includes a first sample and a calibration sample. The position of the sample holder relative to the resonator is calibrated. After calibrating the position of the sample holder, the sample holder is translated to position the first sample in the sample region. Magnetic resonance data is acquired based on magnetic resonance signals generated by an interaction between the resonator and the first sample.

Abstract: A method is presented for controlling a spin system in an external magnetic field. The method includes sending a first pulse to a resonator over a first period. The resonator generates a magnetic field in response to receiving the first pulse. Moreover, the resonator applies the magnetic field to the spin system and the first pulse maintains the magnetic field in a transient state during the first period. The method also includes sending a second pulse to the resonator over a second period immediately following the first period. The resonator alters a magnitude of the magnetic field to zero in response to receiving the second pulse. Other methods are presented for controlling a spin system in an external magnetic field, including systems for controlling a spin system in an external field.

Abstract: In some aspects, a control system interacts with a quantum system. In some instances, the quantum system includes qubits that respond to a control signal generated by the control system, and the control system is configured to generate the control signal in response to an input signal. A control sequence (which may include, for example, a sequence of values for the input signal) can be generated by a computing system based on a target operation to be applied to the qubits. The control sequence can be generated based on the target operation, a quantum system model, a distortion model and possibly other information. The quantum system model represents the quantum system and includes a control parameter representing the control signal. The distortion model represents a nonlinear relationship between the control signal and the input signal. The control sequence is applied to the quantum system by operation of the control system.

Abstract: In some aspects, a control system interacts with a quantum system. In some instances, the quantum system includes qubits that respond to a control signal generated by the control system, and the control system is configured to generate the control signal in response to an input signal. A control sequence (which may include, for example, a sequence of values for the input signal) can be generated by a computing system based on a target operation to be applied to the qubits. The control sequence can be generated based on the target operation, a quantum system model, a distortion model and possibly other information. The quantum system model represents the quantum system and includes a control parameter representing the control signal. The distortion model represents a nonlinear relationship between the control signal and the input signal. The control sequence is applied to the quantum system by operation of the control system.

Abstract: In some aspects, a control system interacts with a quantum system. In some instances, the quantum system includes qubits that respond to a control signal generated by the control system, and the control system is configured to generate the control signal in response to an input signal. A control sequence (which may include, for example, a sequence of values for the input signal) can be generated by a computing system based on a target operation to be applied to the qubits. The control sequence can be generated based on the target operation, a quantum system model, a distortion model and possibly other information. The quantum system model represents the quantum system and includes a control parameter representing the control signal. The distortion model represents a nonlinear relationship between the control signal and the input signal. The control sequence is applied to the quantum system by operation of the control system.

Abstract: In some aspects, a control system interacts with a quantum system. IN some instances, the quantum system includes qubits that respond to a control signal generated by the control system, and the control system is configured to generate the control signal in response to an input signal. A control sequence (which may include, for example, a sequence of values for the input signal) can be generated by a computing system based on a target operation to be applied to the qubits. The control sequence can be generated based on the target operation, a quantum system model, a distortion model and possibly other information. The quantum system model represents the quantum system and includes a control parameter representing the control signal. The distortion model represents a nonlinear relationship between the control signal and the input signal. The control sequence is applied to the quantum system by operation of the control system.

Abstract: A quantum information processor can include a control system and a system of processor nodes. Each of the processor nodes can include multiple qubits and an actuator. The control system can manipulate the qubits of multiple processor nodes based on cross-node quantum interactions between the qubits. In some instances, the control system may perform multi-qubit quantum gates on qubits of different processor nodes based on the cross-node quantum interactions. Within each processor node, the qubits interact with the actuator by an intra-node quantum coupling. Between processor nodes, the actuators interact with each other by an inter-node quantum coupling. The cross-node quantum interaction can be produced by non-commutivity of the intra-node quantum couplings and the inter-node quantum couplings. In some instances, the qubits can be manipulated by applying a control sequence that produces an interaction frame where the cross-node quantum interaction dominates the time evolution of the system.