Realizing a long coherence time quantum memory is crucial for quantum technology. This paper reports achieving a coherence time of approximately 5500 seconds for a single ¹⁷¹Yb⁺ ion qubit, significantly exceeding previous records. This was accomplished by identifying and suppressing limiting factors such as magnetic field fluctuations, frequency instability, and microwave leakage. The decoherence process was systematically studied using quantum process tomography and analyzed with resource theories of quantum memory and coherence. This advancement is expected to accelerate the practical applications of quantum memories in various quantum information processing tasks.

Pengfei Wang, Chun-Yang Luan, Mu Qiao, Mark Um, Junhua Zhang, Ye Wang, Xiao Yuan, Mile Gu, Jingning Zhang, Kihwan Kim