qc.cx(0, 1, ctrl_state=0) fails - AerError: 'unknown instruction: cx_o0' about qiskit-aer HOT 4 CLOSED

I'd like to work on this. Could you tell me what is supposed to be done? Do we need to check if _o is present in name in _assemble_op() in aer_compiler.py ?

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This is not a bug. qc.cx(0, 1, ctrl_state=0) inserts cx_o0 gate which is not cx. The name is defined here. cx_o0 gate is not in basis_gates of AerSimulator. You need to transpile the circuit as follows:

qc = QuantumCircuit(2)
qc.cx(0, 1, ctrl_state=0)
qc.measure_all()

simulator = AerSimulator()
qc = transpile(qc, simulator)
simulator.run(qc).result().get_counts()

transpiler generates a sequence of x, cx, and x gates.

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Yes, in that sense it's a feature request. In previous version Aer seems to have accepted both cx and cx_o0.

Resolving it with transpilation adds some overhead in transpiling on larger circuits, but I suppose it might not be that big of an issue. I don't have a strong opinion on this one. I guess I am fine to resolve the issue here by just leaving it as is, and using the transpiler

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Thank you

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