Optimization of partially isolated quantum harmonic oscillator memory systems by mean square decoherence time criteria
<|reference_start|>Optimization of partially isolated quantum harmonic oscillator memory systems by mean square decoherence time criteria: This paper is concerned with open quantum harmonic oscillators with position-momentum system variables, whose internal dynamics and interaction with the environment are governed by linear quantum stochastic differential equations. A recently proposed approach to such systems as Heisenberg picture quantum memories exploits their ability to approximately retain initial conditions over a decoherence horizon. Using the quantum memory decoherence time defined previously in terms of a fidelity threshold on a weighted mean-square deviation of the system variables from their initial values, we apply this approach to a partially isolated subsystem of the oscillator, which is not directly affected by the external fields. The partial isolation leads to an appropriate system decomposition and a qualitatively different short-horizon asymptotic behaviour of the deviation, which yields a longer decoherence time in the high-fidelity limit. The resulting approximate decoherence time maximization over the energy parameters for improving the quantum memory performance is discussed for a coherent feedback interconnection of such systems.<|reference_end|>
@article{vladimirov2024optimization,
    title={Optimization of partially isolated quantum harmonic oscillator memory
  systems by mean square decoherence time criteria},
    author={Igor G. Vladimirov, Ian R. Petersen},
    journal={arXiv preprint arXiv:2409.15720},
    year={2024},
    archivePrefix={arXiv},
    eprint={2409.15720},
    primaryClass={quant-ph cs.SY eess.SY math.OC}
}