Understanding and Improving Critical Metrology. Quenching Superradiant Light-Matter Systems Beyond the Critical Point
Understanding and Improving Critical Metrology. Quenching Superradiant Light-Matter Systems Beyond the Critical Point
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DOI：
10.22331/q-2022-04-27-700
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发表时间：
2021-10
期刊：
影响因子：
6.4
通讯作者：
K. Gietka;Lewis Ruks;T. Busch
中科院分区：
文献类型：
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作者：
K. Gietka;Lewis Ruks;T. Busch
我们仔细研究了临界计量学，并提出了一种改进的临界量子计量学协议，该协议依赖于猝灭表现出超出临界点的超辐射量子相变的系统。我们表明，这种方法可以导致指数增加的量子Fisher信息的时间相对于现有的临界量子计量协议依赖于淬火接近临界点和观察幂律行为。我们证明了在我们的协议中，Cram\'er-Rao界限可以饱和，通过标准的零差检测方案。我们明确地显示了它的优势，使用原型设置的迪凯模型和探索耦合到一个单模腔场的量子气体作为一个潜在的平台。在这种情况下，一个额外的指数增强的量子Fisher信息可以在实践中观察到的原子数N $在腔中，即使在没有$N $体耦合项。
We carefully examine critical metrology and present an improved critical quantum metrology protocol which relies on quenching a system exhibiting a superradiant quantum phase transition beyond its critical point. We show that this approach can lead to an exponential increase of the quantum Fisher information in time with respect to existing critical quantum metrology protocols relying on quenching close to the critical point and observing power law behaviour. We demonstrate that the Cram\'er-Rao bound can be saturated in our protocol through the standard homodyne detection scheme. We explicitly show its advantage using the archetypal setting of the Dicke model and explore a quantum gas coupled to a single-mode cavity field as a potential platform. In this case an additional exponential enhancement of the quantum Fisher information can in practice be observed with the number of atoms $N$ in the cavity, even in the absence of $N$-body coupling terms.