Efficient manipulation of light at the single quanta level is a long-standing goal in quantum optics, due to its importance for quantum communications, computations and testing of fundamental quantum mechanics. However, performing such quantum operations on photons in a deterministic way turns out to be extremely hard, as photons usually don’t interact with each other.

Ensemble of cold Rydberg atoms features strong atomic interaction and excellent matter-light quantum interface. By coupling photons with high-lying Rydberg states, we can effectively engineer atom-photon and even photon-photon interactions. We have built a Rydberg quantum optics experiment and realized the efficient generation of non-classical light states and high-fidelity entanglement. Long-term goal includes deterministic preparation of multi-photon entanglement, high fidelity photonic quantum logic gates and Rydberg-based quantum networks.

Quantum computer holds the promise to tackle many problems intractable with its classical counterparts. However, its physical realization has been hindered by many outstanding challenges, such as the qubits scalability and operation fidelity. We have built a highly controllable Rydberg atomic array platform for quantum computing and quantum simulation studies. 2-D atomic array with arbitrary configuration can be programed and implemented, leading to good scalability. Fast and efficient quantum operation between qubits can be achieved by exploiting the strong and long-range Rydberg interactions. We have realized the preparation of defect-free atomic arrays and the efficient manipulation of Rydberg qubits. Our long-term goal includes improving the scalability, coherent time and gate fidelity of the system for the implementation of quantum computing and quantum simulation protocols.

Microwave (MW) technology is one of the cornerstones in modern society. Breakthroughs in microwave measurement technology have profound impacts on cosmology, resource exploration, medical imaging, wireless communications and many other fields. We are developing novel MW sensing technologies with Rydberg atoms, which have giant electric dipole moments. Such a Rydberg quantum sensor features excellent sensitivity to MW fields and holds the promise to go beyond the fundamental limit of classical MW detectors, i.e., the Johnson–Nyquist noise limit. Moreover, unlike its classical counterparts with limited frequency tunability, a Rydberg-based sensor can measure electromagnetic fields with frequencies ranging from DC to almost Terahertz, by exploring the abundant Rydberg atomic levels. We have realized a MW detection sensitivity of ~20 nV/cm Hz^(-1/2), and demonstrated non-destructive MW measurements and information transfer. Future research will focus on implementing high-speed wireless communications and achieving MW detection capability beyond classical devices.