2

How can I put the unitary matrix $$e^\frac{i\pi}{2}I$$ to the quantum circuit?

I don't know if it is belong to $$U3(\theta, \phi, \lambda), U2(\phi, \lambda), U1(\lambda)$$

Thanks a lot.

2

How can I put the unitary matrix $$e^\frac{i\pi}{2}I$$ to the quantum circuit?

I don't know if it is belong to $$U3(\theta, \phi, \lambda), U2(\phi, \lambda), U1(\lambda)$$

Thanks a lot.

2

$I$ is the identity matrix. In a quantum circuit, it means "do nothing". You don't need to program it in. The global phase doesn't make a difference to this either.

2FWIW you can add global phases in Qiskit,

`circuit = QuantumCircuit(1); circuit.global_phase = pi/2`

– Cryoris – 2020-09-16T15:25:14.080Thanks a lot, I know sth! – Physics World – 2020-09-16T17:36:34.913

$e^\frac{i\pi}{2}=i$, so it rotates the phase by 90${}^\circ$. – peterh - Reinstate Monica – 2020-09-17T15:50:41.000