AWS Braket Qubit Executor

This quantum executor accesses quantum resources operating under the qubit model as made available through AWS ("braket.aws.qubit").

It utilizes the Pennylane plugin found here. BraketQubitExecutor introduces thread-based parallelism for circuit execution on the "braket.aws.qubit" device.

1. Installation

BraketQubitExecutor is not included in base Covalent. To use it, you will need to install the Covalent with:

pip install covalent[braket]

and have valid AWS credentials as specified here.

2. Usage Example

Using BraketQubitExecutor requires specifying an AWS Quantum backend through the device_arn argument.

# Statevector simulator
sv1 = ct.executor.BraketQubitExecutor(
    device_arn="arn:aws:braket:::device/quantum-simulator/amazon/sv1",
    shots=1024,
    s3_destination_folder=(),
)
# Tensor network simulator
tn1 = ct.executor.BraketQubitExecutor(
    device_arn="arn:aws:braket:::device/quantum-simulator/amazon/tn1",
    shots=1024,
    s3_destination_folder=(),
)

@ct.qelectron(executors=[sv1, tn1])
@qml.qnode(qml.device("default.qubit", wires=2, shots=1000))
def circuit(x):
    qml.IQPEmbedding(features=x, wires=[0, 1])
    qml.Hadamard(wires=1)
    return [qml.expval(qml.PauliZ(0)), qml.expval(qml.PauliZ(1))]

As a QElectron, the circuit can be called either normally or asynchronously using circuit.run_later(). With the default "cyclic" selector, circuit calls will alternate between the executors, [sv1, tn1].

Synchronous example output is below

>>> print(circuit([0.5, 0.1]))  # alternate between sv1 and tn1

[array(0.008), array(0.996)]

and asynchronously:

>>> x = [0.6, -1.57]

>>> # Queue jobs for all three circuit calls simultaneously on AWS Braket.
>>> # Uses same executor order as above (sv1, tn1, ...).
>>> futs = [circuit.run_later(x) for _ in range(3)]

>>> # Wait for all circuits to finish.
>>> [fut.result() for fut in futs]

[[array(-0.02), array(0.01)],
 [array(0.014), array(-0.022)],
 [array(-0.074), array(0.05)]]

3. Overview of Configuration

The BraketQubitExecutor configuration is found under [qelectron.BraketQubitExecutor] in the Covalent configuration file.

Config Key	Is Required	Default	Description
device_arn	Yes	“” (blank string)	A unique identifier used to represent and reference AWS resources. Stands for “Amazon Resource Name”.
poll_timeout_seconds	No	432000	Number of seconds before a poll to remote device is considered timed-out.
poll_interval_seconds	No	1	Number of seconds between polling of a remote device’s status.
max_connections	No	100	the maximum number of connections in the Boto3 connection pool.
max_retries	No	3	The maximum number of times a job will be re-sent if it failed.

4. Required Cloud Resources

Users must acquire AWS credentials and make them discoverable following the instructions here.

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