hybridlane.devices.sandia_qscout

Module for all QSCOUT-related functionality [1]

Device details (sandiaqscout.hybrid)

The device supports up to 6 qubits (ions) and their associated motional modes. By default, the center-of-mass (COM) modes are disabled due to their higher noise levels, but they can be enabled by setting the enable_com_modes option to True when initializing the device. Thus for a circuit with \(n\) qubits, there are \(2n-2\) motional modes available by default, or \(2n\) if the COM modes are enabled.

Wires The device supports hardware wires and virtual wires. Hardware qubits are addressed with integers \(0\) to \(5\), while motional modes are addressed using the Qumode object or strings of the form "m{manifold}i{index}", where manifold is 1 for the lower motional manifold and 0 for the upper manifold, and index is the index of the mode.

Example with hardware wires:

dev = qml.device("sandiaqscout.hybrid", use_virtual_wires=False, n_qubits=4)

@qml.set_shots(10)
@qml.qnode(dev)
def circuit():
    hqml.FockState(3, [0, "m1i2"])
    return hqml.expval(qml.Z(0))

print(qml.draw(circuit)())

When using hardware wires, the user is responsible for ensuring that gates adhere to any constraints. Additionally, for optimal performance, the qubits and qumodes should be chosen to maximize coupling strengths to reduce gate time. The lower manifold (1) has stronger couplings.

By default, the device uses virtual wire allocation to assign physical wires to virtual wires based on constraints of the gates in the circuit. This can be disabled by setting use_virtual_wires to False when initializing the device, in which case the circuit must use only physical wires.

Example with virtual wires:

qml.decomposition.enable_graph()
dev = qml.device("sandiaqscout.hybrid", n_qubits=4)

@qml.set_shots(10)
@qml.qnode(dev)
def circuit():
    hqml.FockState(3, ["q", "m"])
    return hqml.expval(qml.Z("q"))

print(qml.draw(circuit, level="device")())

Note that virtual wire allocation does not yet perform any ranking for valid solutions or noise-aware compilation.

Native gates: The native gate set includes common qubit gates and some hybrid gates, particularly implementing the Sideband ISA [2]. The native gates are available in hybridlane.devices.sandia_qscout.ops and currently include:

  • Qubit gates: \(R_\phi, R_x, R_y, R_z, S, S^\dagger, S_x, S_x^\dagger, XX, YY, ZZ\)

  • Hybrid gates: \(JC, AJC, xCD, yCD, zCD, xCS, BS\)

Exporting to Jaqal

To run on the ion trap, circuits need to be exported to the Jaqal [3] language. Hybridlane provides the to_jaqal() function to convert a QNode to a Jaqal program. By using that function on a QNode bound to the QSCOUT device, the resulting Jaqal program will be optimized for the device’s native gate set and constraints.

Example:

dev = qml.device("sandiaqscout.hybrid", n_qubits=2)

@qml.set_shots(1024)
@qml.qnode(dev)
def circuit(alpha):
    hqml.SqueezedCatState(alpha, np.pi / 2, parity="even", wires=["q", "m1i1"])

to_jaqal(circuit, level="device", precision=4)(4)

This will return a Jaqal string, where each tape of the QNode batch is encoded as a subcircuit.

from Calibration_PulseDefinitions.QubitBosonPulses usepulses *

register q[2]

subcircuit {
    xCD q[1] 1 1 4.0 0.0
    Rz q[1] 11.00
    xCD q[1] 1 1 0.0 0.09817
    yCD q[1] 1 1 -0.09817 -0.0
    Sz q[1]
}

References

Submodules

Classes

QscoutIonTrap

Backend that prepares circuits for the Sandia QSCOUT ion trap

Qumode

Hardware qumode on the ion trap device.

Functions

get_compiler([optimize, max_qubits, enable_com_modes, ...])

Returns a compilation pipeline for QscoutIonTrap device

get_default_style()

Gives some defaults for drawing circuits using hqml.draw_mpl

batch_to_jaqal(batch[, precision])

to_jaqal(qnode[, level, precision])

Package Contents

hybridlane.devices.sandia_qscout.get_compiler(optimize=True, max_qubits=None, enable_com_modes=False, use_virtual_wires=True)[source]

Returns a compilation pipeline for QscoutIonTrap device

Parameters:

  • optimize (bool) – Whether to perform any simplifications of the circuit including cancelling inverse gates, merging consecutive rotations, and commuting controlled operators

  • max_qubits (int | None) – The number of qubits per circuit. If None (default), this will be inferred from each circuit. By setting this number to more qubits than are used in the circuit, this can grant access to additional qumodes.

  • enable_com_modes (bool) – If True, the center-of-mass qumodes are enabled. As they are likely to be very noisy due to heating, they are disabled by default.

  • use_virtual_wires (bool) – If True (default), the circuit may contain algorithmic (virtual) wires that will be mapped to physical wires by the compiler. If False, the circuit must contain only physical wires.

Return type:

CompilePipeline

hybridlane.devices.sandia_qscout.get_default_style()[source]

Gives some defaults for drawing circuits using hqml.draw_mpl

This adds the following styles to a quantum circuit:

  • Qubits are listed before qumodes, and qumodes are plotted from low to high (in

    terms of mode)

  • Qumodes are colored by their mode to be rainbow

This only works if drawing a circuit at the device level, after the circuit wires have been mapped to the hardware wires of the QscoutIonTrap device.

hybridlane.devices.sandia_qscout.batch_to_jaqal(batch, precision=20)[source]
Parameters:
Return type:

LiteralString

hybridlane.devices.sandia_qscout.to_jaqal(qnode, level='user', precision=20)[source]
Parameters: