Selective darkening of degenerate transitions for implementing quantum controlled-NOT gates

Understand

We present a theoretical analysis of the selective darkening method for implementing quantum controlled-NOT (CNOT) gates.

• This method, which we recently proposed and demonstrated, consists of driving two transversely-coupled quantum bits (qubits) with a driving field that is resonant with one of the two qubits.
• For specific relative amplitudes and phases of the driving field felt by the two qubits, one of the two transitions in the degenerate pair is darkened, or in other words, becomes forbidden by effective selection rules.
• At these driving conditions, the evolution of the two-qubit state realizes a CNOT gate.