Operation Interface

It is possible to add custom operations to the MonitoredQuantumCircuits.jl framework. However, this process may require familiarity with each backend that should support your new operation.

Basic Requirements

Regardless of the backend, you must implement a few essential methods. Begin by defining a new type, either as a subtype of Operation or MeasurementOperation (if your operation involves measurements). The circuit construction logic relies on the following interface methods, which must be implemented for your operation:

• nQubits(::MyOperation) Specifies the number of qubits the operation acts upon.

• isClifford(::MyOperation) Indicates whether the operation is a Clifford operation.

Backend Integration

For each backend that should support your operation, you must implement the corresponding apply! method.

Example

Below is an example implementation of the Id (identity) gate:

import MonitoredQuantumCircuits: Operation, nQubits, isClifford
import MonitoredQuantumCircuits: Qiskit, QuantumClifford, apply!

struct Id <: Operation end

nQubits(::Id) = 1
isClifford(::Id) = true

# Qiskit backend implementation
function apply!(backend::Union{IBMBackend, AerSimulator}, ::Id, p::Integer)
    qc = get_circuit(backend)
    qc.id(p - 1)
    return backend
end

# QuantumClifford backend implementation
function apply!(backend::TableauSimulator, ::Id, p::Integer)
    QuantumClifford.QC.apply!(backend.state, QuantumClifford.QC.sId1(p))
    return backend
end

By following this approach, you can ensure that your custom operation integrates seamlessly with the MonitoredQuantumCircuits.jl framework and is supported across the desired backends.