Simultaneous control of exchange interactions for efficient quantum gate operations in spin qubit systems

Simultaneous control of exchange interactions between spin qubits has attracted increasing interest in recent years, driven by advances in experimental platforms and calibration techniques. We theoretically investigate a triple quantum dot system, with each dot singly occupied by an electron spin. We demonstrate that the time evolution of the system with multiple exchange interactions concurrently on naturally leads to a generic three-qubit entangling gate. We derive an explicit analytical expression for this gate and show its effectiveness in implementing quantum circuits for several standard quantum computing tasks. Furthermore, we show that simultaneous exchange control enables the realization of novel gate operations for exchange-only qubits.