Linpeng Xiayu, Bresque Léa, Maffei Maria, Jordan Andrew N, Auffèves Alexia, Murch Kater W
Department of Physics, Washington University, St. Louis, Missouri 63130, USA.
Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France.
Phys Rev Lett. 2022 Jun 3;128(22):220506. doi: 10.1103/PhysRevLett.128.220506.
Quantum measurements are basic operations that play a critical role in the study and application of quantum information. We study how the use of quantum, coherent, and classical thermal states of light in a circuit quantum electrodynamics setup impacts the performance of quantum measurements, by comparing their respective measurement backaction and measurement signal to noise ratio per photon. In the strong dispersive limit, we find that thermal light is capable of performing quantum measurements with comparable efficiency to coherent light, both being outperformed by single-photon light. We then analyze the thermodynamic cost of each measurement scheme. We show that single-photon light shows an advantage in terms of energy cost per information gain, reaching the fundamental thermodynamic cost.
量子测量是基本操作，在量子信息的研究和应用中起着关键作用。我们通过比较电路量子电动力学装置中光的量子态、相干态和经典热态各自的测量反作用以及每个光子的测量信噪比，研究它们对量子测量性能的影响。在强色散极限下，我们发现热光能够以与相干光相当的效率执行量子测量，而这两种光的效率都不如单光子光。然后我们分析了每种测量方案的热力学成本。我们表明，单光子光在每获得一个信息的能量成本方面具有优势，达到了基本的热力学成本。
