A method is provided for entangling a quantum state of a qubit with a quantum
state
of a resonant control system. The method comprises tuning the resonant control
system, which is capacitively or inductively coupled to the qubit, to a resonant
frequency for a period of time. The resonant frequency corresponds to an energy
difference between a first energy level of the qubit and a second energy level
of the qubit. The act of tuning entangles the quantum state of the qubit with the
quantum state of the resonant control system. A representative resonant control
system includes a Josephson junction. A method is also provided for entangling
a quantum state of a qubit, within a plurality of qubits, with a quantum state
of a resonant control system.