Fig. 3From: An elementary review on basic principles and developments of qubits for quantum computingGeneral approaches to establish qubit-qubit entanglements. a Some qubit platforms have direct qubit-qubit interactions by nature, which are persistent during the computation process. Controllable interaction can be achieved by introducing b auxiliary quantum states or c auxiliary quantum systems while maintaining the isolation of qubits. Blue arrows indicate interaction channels between quantum states or systemsBack to article page