2015/02/25 by JunYan Luo, Luo, JunYan, Jinshuang Jin +9
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph) #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.48550/arxiv.1502.07098
10 pages, 5 figres
arxiv created 2015/02/25 · openalex publication_date 2015/02/25 · arxiv updated 2015/02/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In the context of a charge qubit under continuous monitoring by a single electron transistor, we propose an unraveling of the generalized quantum Markovian master equation into an ensemble of individual quantum trajectories for stochastic point process. A suboptimal feedback algorism is implemented into individual quantum trajectories to protect a desired pure state. Coherent oscillations of the charge qubit could be maintained in principle for an arbitrarily long time in case of sufficient feedback strength. The effectiveness of the feedback control is also reflected in the detector's noise spectrum. The signal-to-noise ratio rises significantly with increasing feedback strength such that it could even exceed the Korotkov-Averin bound in quantum measurement, manifesting almost ideal quantum coherent oscillations of the qubit. The proposed unraveling and feedback protocol may open up the prospect to sustain ideal coherent oscillations of a charge qubit in quantum computation algorithms.