2023/10/19 by Ji-Bing Yuan, Zhi-Min Tang, Yuan, Ji-Bing +11 · 1 citation
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Mechanical and Optical Resonators #Quantum Information and Cryptography #Quantum Physics (quant-ph) #Quantum optics and atomic interactions
paper · pdf · doi:10.48550/arxiv.2310.12445
openalex publication_date 2023/10/19 · openalex created_date 2023/10/21 · openalex updated_date 2026/07/28
We investigate the utilization of a single generalized dephasing qubit for sensing a quantum reservoir, where the antisymmetric coupling between the qubit and its reservoir is broken. It is found that in addition to the decay factor encoding channel, the antisymmetric coupling breaking gives rise to another phase factor encoding channel. We introduce an optimal measurement for the generalized dephasing qubit which enables the practical measurement precision to reach the theoretical ultimate precision quantified by the quantum signal-to-noise ratio (QSNR). As an example, the generalized dephasing qubit is employed to estimate the s-wave scattering length of an atomic Bose-Einstein condensate. It is found that the phase-induced QSNR caused by the antisymmetric coupling breaking is at least two orders of magnitude higher than the decay-induced QSNR at the millisecond timescale and the optimal relative error can achieve a scaling ∝ 1/t with t being the encoding time in long-term encoding. Our work opens a way for supersensitive sensing of quantum reservoirs.