论文标题
宽带传感的机会和局限性
Opportunities and Limitations in Broadband Sensing
论文作者
论文摘要
我们考虑估计将耦合到两级传感器的单色AC信号的大小。对于任何检测方案，达到的精度取决于信号的频率，并且可以通过量子渔民信息来量化。为了研究宽带传感的局限性，我们介绍了综合的量子渔民信息，并得出了在任何传感方案中体现基本权衡的不平等范围。这些不平等表明，一个频率范围内的灵敏度必须以其他地方的灵敏度降低。对于许多协议，包括那些累积较小的协议和由$π$ - 泵组成的协议，我们发现集成的Fisher Information用$ t $线性地缩放。我们还发现具有实质相累积的协议可以具有集成的QFI，该QFI与$ t $相互繁殖，这是最佳的。这些协议可以在非常宽的带宽上非常快速检测具有未知频率的信号。
We consider estimating the magnitude of a monochromatic AC signal that couples to a two-level sensor. For any detection protocol, the precision achieved depends on the signal's frequency and can be quantified by the quantum Fisher information. To study limitations in broadband sensing, we introduce the integrated quantum Fisher information and derive inequality bounds that embody fundamental tradeoffs in any sensing protocol. These inequalities show that sensitivity in one frequency range must come at a cost of reduced sensitivity elsewhere. For many protocols, including those with small phase accumulation and those consisting of $π$-pulses, we find the integrated Fisher information scales linearly with $T$. We also find protocols with substantial phase accumulation can have integrated QFI that grows quadratically with $T$, which is optimal. These protocols may allow the very rapid detection of a signal with unknown frequency over a very wide bandwidth.
