iqm.error_reduction_tools.twirling.twirling_modifiers.process_cz_gate

iqm.error_reduction_tools.twirling.twirling_modifiers.process_cz_gate(operation, new_circuit, registers)

Process a CZ gate: propagate pending π-rotation parity as Z kicks.

A CZ gate commutes with Z rotations but cojugates a R(π, φ) rotations as:

--[R(π, φ) ⊗ I]--[CZ]-- = --[CZ]--[R(π, φ) ⊗ Z]--

So, if there is a pending π-rotation on one qubit, a Z rotation of π is added to the other qubit.

Parameters:

• operation (CircuitOperation) – The CZ CircuitOperation to process.

• new_circuit (TwirledCircuit) – The new circuit being built.

• registers (TrackingRegisters) – Tracking registers for Z and π-rotation state.

Return type:

None