Fig. 5. Parallel operation.

(A to C) Simultaneous operation of controlled-phase shuttling (A), two-qubit √ ______ SWAP  operations (B), and spin-to-charge conversion (C) can be achieved in a line-by-line manner. In each figure, inset (1) denotes the energy-detuning diagram of the targeted qubit(s). Insets (2) and (3) show the consequence on the remaining qubits, where detuning, tunnel coupling, or the local magnetic field minimizes errors. (D and E) Shuttling without phase control (D) and charge readout (E) can be performed in a near-global manner. (A) Shuttling of qubits. Parallelism is obtained along one direction, and tunability is obtained along another direction, and the respective gates control the timing and detuning to overcome qubit-to-qubit variations. Here, the target qubits shuttle from column to column, whereas the other qubits are blocked by ε or t₀. (B) Two-qubit logic gates. √ ______ SWAP  operations only occur between tunnel-coupled neighboring qubits. The remaining qubits do not interact but could shuttle in a column. The resulting (small) phase shift can be corrected by the consecutive shuttle event in the line-by-line operation. In (C), Pauli spin blockade spin-to-charge conversion occurs between tunnel-coupled qubits. Qubits coupled to an empty dot do not shuttle, prevented by the energy alignment, since we require Δμ < E_C. (D) Shuttling without phase control enables to construct a variety of shuttle patterns that can be operated almost globally; the schematic here shows the simultaneous shuttling of half of the qubits one site to the right. (E) The dispersive charge readout, performed after the spin-to-charge conversion shown in (C), can be performed simultaneously by including frequency multiplexing. The RF carrier on QL (f_d) is then modulated by the application of additional multiplexing RF pulses (f_m) to RL.