Title: Exponentially enhanced quantum metrology using resources of linear complexity
Speaker: Dr. Xiaoting Wang 王晓霆 (电子科技大学)
Venue: 腾讯会议https://meeting.tencent.com/s/YkNtrnGaJyUS 会议 ID：942 138 480
Abstract:
The coherent interaction time provides an important type of serial resource in quantum metrology, where seeking a higher-order time scaling in quantum Fisher information(QFI) is crucial to achieve sensitivity enhancement. In this work, we propose a generalized model where the signal to be estimated is coupled to only one part of the total Hamiltonian, making it possible to utilize the non-commutativity of operators to increase QFI. In particular, two specific models are presented: for the qubit-oscillator Ramsey interferometer, the QFI has a quartic time scaling; for a chain of coupled harmonic resonators, with the numbers of resonators and their interactions both linear in time, the QFI can achieve an exponential time scaling. Our results show that linear scaling in both time and physical resource is sufficient to achieve exponential enhancement of sensitivity.