물리학과에서는 특별세미나를 아래와 같이 개최하오니 관심있는 분들의 많은 참석을 바랍니다.
Recent advances of quantum information processors have opened up new horizons in science and technology. Big Tech companies have made great strides in the scale and performance, but many challenges remain on the journey to achieving useful quantum technology. In this talk, I present Hamiltonian engineering methods to overcome two key challenges of fixed-frequency superconducting devices. The first challenge is that the interaction range of superconducting qubits is typically limited to their nearest neighbors. Thus, it was strongly believed that multi-qubit gates could only be implemented by synthesizing multiple two-qubit and single-qubit gates. Going beyond this common belief, we implement a high-fidelity three-qubit iToffoli gate for the first time by simultaneously applying two-qubit interactions with non-commuting local operations. This method not only brings a high-fidelity three-qubit gate to current superconducting quantum processors but also opens a pathway for developing multi-qubit gates based on two-qubit interactions. The second challenge is that many emerging quantum architectures have fixed spectra to achieve high coherence, but as a result, the types of controllable interactions are limited. Endowing these promising platforms with the same interaction toolbox available to frequency-tunable devices will significantly extend their capabilities and performance. To this end, we adiabatically transform fixed-frequency superconducting circuits into modifiable Floquet qubits, and demonstrate an XXZ Heisenberg interaction with fully adjustable anisotropy. Importantly, our Floquet protocol is applicable to various fixed-frequency high-coherence platforms, thereby unlocking a suite of essential interactions for many-body quantum simulation and efficient quantum computing. From a broader perspective, our work provides compelling avenues for future exploration of quantum electrodynamics and optimal control using the Floquet framework.