论文标题
传感器的量子能力
Quantum Capacities of Transducers
论文作者
论文摘要
高性能量子传感器可以在不同的物理载体之间忠实地转换量子信息，这是量子科学和技术的基本要素。为了评估它们连贯传递量子信息的能力，量子传感器通常以不同的功绩图为特征，包括转换效率，带宽和增加的噪声。在这里，我们利用量子能力的概念，这是通过通道可实现的量子沟通率最高的量子，以量化传感器的性能。通过评估整个转换带的连续量子能力，量子容量可以用作单个度量标准，该度量可以统一传感器的各种理想标准 - 高效率，较大的带宽和低噪声。此外，使用骨气纯损失通道的量子能力作为基准，我们研究了通过通过耦合的玻感链传输外部信号实现的通用量子转导方案的最佳设计。 Under the physical constraint of a bounded maximal coupling rate $g_{\rm max}$, the highest continuous-time quantum capacity $Q^{\rm max} \approx 31.4 g_{\rm max}$ is achieved by transducers with a maximally flat conversion frequency response, analogous to Butterworth electric filters.我们进一步扩展了我们的方法，以通过考虑换能器的量子能力上的上限和下限来包括热噪声，并在热损耗的效果下表征最大平坦的换能器的性能。
High-performance quantum transducers, which can faithfully convert quantum information between disparate physical carriers, are essential elements in quantum science and technology. To assess their ability to coherently transfer quantum information, quantum transducers are typically characterized by different figures of merit including conversion efficiency, bandwidth, and added noise. Here we utilize the concept of quantum capacity, the highest achievable qubit communication rate through a channel, to quantify the performance of a transducer. By evaluating the continuous-time quantum capacity across the conversion band, quantum capacity can serve as a single metric that unifies various desirable criteria of a transducer -- high efficiency, large bandwidth, and low noise. Moreover, using the quantum capacities of bosonic pure-loss channels as benchmarks, we investigate the optimal designs of generic quantum transduction schemes implemented by transmitting external signals through a coupled bosonic chain. Under the physical constraint of a bounded maximal coupling rate $g_{\rm max}$, the highest continuous-time quantum capacity $Q^{\rm max} \approx 31.4 g_{\rm max}$ is achieved by transducers with a maximally flat conversion frequency response, analogous to Butterworth electric filters. We further extend our method to include thermal noise by considering upper and lower bounds on the quantum capacities of transducers and characterize the performance of maximally flat transducers under the effect of thermal loss.
