Ko Liwen, Cook Robert L, Whaley K Birgitta
Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States.
Kavli Energy Nanoscience Institute at Berkeley, Berkeley, California 94720, United States.
J Phys Chem Lett. 2023 Sep 14;14(36):8050-8059. doi: 10.1021/acs.jpclett.3c01714. Epub 2023 Aug 31.
We show that for a class of quantum light spectroscopy (QLS) experiments using = 0, 1, 2, ··· classical light pulses and an entangled photon pair (a biphoton state) where one photon acts as a reference without interacting with the matter sample, identical signals can be obtained by replacing the biphotons with classical-like coherent states of light, where these are defined explicitly in terms of the parameters of the biphoton states. An input-output formulation of quantum nonlinear spectroscopy is used to prove this equivalence. We demonstrate the equivalence numerically by comparing a classical pump-quantum probe experiment with the corresponding classical pump-classical probe experiment. This analysis shows that understanding the equivalence between entangled biphoton probes and carefully designed classical-like coherent state probes leads to quantum-inspired classical experiments that yield equivalent signals and provides insights for the future design of QLS experiments that could provide a true quantum advantage.
我们表明，对于一类使用(n = 0, 1, 2, \cdots)个经典光脉冲和一个纠缠光子对（双光子态）的量子光光谱（QLS）实验，其中一个光子作为参考而不与物质样本相互作用，通过用类经典相干光态替换双光子可以获得相同的信号，这些类经典相干光态是根据双光子态的参数明确定义的。量子非线性光谱的输入 - 输出公式用于证明这种等价性。我们通过比较经典泵浦 - 量子探测实验与相应的经典泵浦 - 经典探测实验，在数值上证明了这种等价性。该分析表明，理解纠缠双光子探测器与精心设计的类经典相干态探测器之间的等价性，会带来能产生等效信号的受量子启发的经典实验，并为未来可能提供真正量子优势的QLS实验设计提供见解。
