Figure 4
Toffoli gate on hybrid three-qubit systems assisted by one photon with two DOFs.
(a) Two photons A and B jointly control an electron spin e. (b) Two electron spins e1 and e2 jointly control a photon A. (c) One photon A and one electron spin e jointly control a photon B. (d) One photon A and one electron spin e1 jointly control an electron spin e2. S1, S2 and S3 denote the subcircuits shown in Fig. 2(a–c), respectively. S4, S5 and S6 are shown in Fig. 3. The bule lines denote the controlling qubits while the red lines denote the target qubits. The black lines denote an auxiliary photon D in the state 
. MD denotes the measurement of the photon D shown in Fig. 2(c).
