Implementing a Floquet multi-mode coupler by driving a single-mode coupler.

Recent theory and experimental works have explored the possibility of using a multi-mode coupler to couple superconducting qubits. This gives a more efficient way to implement multi-qubit gates. However, designing and fabricating multi-mode couplers requires extra effort compared to single-mode couplers. Here, we present a theory where multi-mode structures can be realised in a single-mode coupler by applying a drive. We use the Floquet theory to analytically and numerically treat the driven system and show that it exhibits multi-mode structures. Our proposal presents a straightforward method for experimentally implementing multi-mode couplers and provides new insights into understanding driven couplers.