近日，墨西哥国立自治大学的Jorge A. Peralta-ángeles&Roberto de J. León-Montiel及其研究团队取得一项新进展。经过不懈努力，他们揭示时频相关在双光子-双原子共振能量转移中的作用。相关研究成果已于2024年10月28日在国际知名学术期刊《物理评论A》上发表。

在这项工作中，研究人员全面探讨了通过自发参量下转换（SPDC）产生的时频相关光子对（其中心频率与单个粒子不共振）对两个无相互作用的二能级原子的联合激发。研究证明，虽然光子间的强频率反相关保证了较高的双光子激发（TPE）概率，但具有正弦基数光谱形状的光子所产生的TPE信号比具有高斯光谱的光子大约强3.8倍。

更重要的是，研究人员发现，对于具有高斯光谱形状的双光子态，抑制时间有序激发路径并不会显著改变TPE概率，而具有正弦基数光谱的光子在双光子激发路径未受抑制时表现出最强的TPE信号。这项研究研究结果不仅有助于阐明时频相关性在SPDC光子共振能量转移中的作用，还为该过程的实验实现所需的最优光源提供了宝贵信息。

据悉，激发能转移是众多化学和生物现象所依赖的一种光物理过程。从天然小分子系统到合成多色团大分子，能量转移涉及电子激发能量从受激供体迁移到受体的过程。尽管这一现象在过去已被广泛研究，但量子技术的快速发展引发了人们对这样一个问题的思考：纠缠光子对等非经典光源是否能在纳米尺度上为人们提供对能量转移更好的控制（或增强）。

附：英文原文

Title: Role of time-frequency correlations in two-photon–two-atom resonance energy transfer

Author: Roberto de J. León-Montiel, Arturo Pedroza-Rojas, Jorge A. Peralta-ángeles

Issue&Volume: 2024/10/28

Abstract: Excitation energy transfer is a photophysical process upon which many chemical and biological phenomena are built. From natural small systems to synthetic multichromophoric macromolecules, energy transfer deals with the process of migration of electronic excitation energy from an excited donor to an acceptor. Although this phenomenon has been extensively studied in the past, the rapid evolution of quantum-enabled technologies has led to the question of whether nonclassical sources of light, such as entangled photon pairs, may provide us with better control (or enhancement) of energy transfer at the nanoscale. In this work we provide a comprehensive study of the joint excitation of two noninteracting two-level atoms by time-frequency-correlated photon pairs (whose central frequencies are not resonant with the individual particles) generated by means of spontaneous parametric down-conversion (SPDC). We demonstrate that while strong frequency anticorrelation between photons guarantees a large two-photon excitation (TPE) probability, photons bearing a sine cardinal spectral shape exhibit an approximately 3.8 times larger TPE signal than photons with a Gaussian spectrum. More importantly, we find that suppression of time-ordered excitation pathways does not substantially modify the TPE probability for two-photon states with a Gaussian spectral shape, whereas photons with a sine cardinal spectrum exhibit the strongest TPE signals when two-photon excitation pathways are not suppressed. Our results not only help elucidate the role of time-frequency correlations in resonance energy transfer with SPDC photons, but also provide valuable information regarding the optimal source to be used in the experimental implementation of said process.

DOI: 10.1103/PhysRevA.110.042431

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.042431