Niels Bohr Institute

Abstract: 
The recent development of quantum technologies has boosted many promising applications ranging from quantum computing, storage, and sensing. Many of those technologies rely on superconducting qubits, spins in solids, and so on, and they work at microwave frequencies. A problem with microwaves is that they are lossy and noisy at room temperature, thus leading to problems interconnecting remote quantum systems. Photons at visible and telecommunication wavelength have superior on long distance transfer without losing their quantum information at room temperature. Building up a transducer that converts quantum information between microwave and optical photons is essential for connecting quantum systems to build a quantum internet. Here, I will present our experimental progress that uses ultracoherent mechanical membrane resonators with quantum decoherent time >100 ms to build up a quantum transducer. The membrane resonator couples to both superconducting microwave resonator and optical resonator with information swap speed much larger than the thermal noise entering rate, thus promising a transducer with high efficiency and added noise below 1 photon.

Bio:
Xiang Xi (习翔), Postdoc fellow of Niels Bohr Institute, Copenhagen, the origin place of modern quantum physics. He got his bachelor's degree from Huazhong University of Science and Technology, Wuhan and then got his Ph.D. degree from the Chinese University of Hong Kong. During Ph.D., his work focused on the fundamental understanding of optical force, integrated phononic circuits, as well as nanophotonics. He joined prof. Albert Schliesser group in Niels Bohr Institute in 2022, as a postdoc. His current work focus on two parts: the first part is to realize quantum transduction and entanglement between microwave and optical photon through optomechanics; the second part is to build up ultra-low loss phononic topological waveguides for on-chip quantum information transfer. He got the Marie sk？odowska-curie postdoctoral fellowship in 2023.