Tiranov Alexey, Lavoie Jonathan, Strassmann Peter C, Sangouard Nicolas, Afzelius Mikael, Bussières Félix, Gisin Nicolas
Group of Applied Physics, University of Geneva, CH-1211 Geneva 4, Switzerland.
Department of Physics, University of Basel, CH-4056 Basel, Switzerland.
Phys Rev Lett. 2016 May 13;116(19):190502. doi: 10.1103/PhysRevLett.116.190502. Epub 2016 May 11.
Quantum mechanics predicts microscopic phenomena with undeniable success. Nevertheless, current theoretical and experimental efforts still do not yield conclusive evidence that there is or is not a fundamental limitation on the possibility to observe quantum phenomena at the macroscopic scale. This question prompted several experimental efforts producing quantum superpositions of large quantum states in light or matter. We report on the observation of quantum correlations, revealed using an entanglement witness, between a single photon and an atomic ensemble of billions of ions frozen in a crystal. The matter part of the state involves the superposition of two macroscopically distinguishable solid-state components composed of several tens of atomic excitations. Assuming the insignificance of the time ordering our experiment indirectly shows light-matter micro-macro entanglement. Our approach leverages from quantum memory techniques and could be used in other systems to expand the size of quantum superpositions in matter.
量子力学在预测微观现象方面取得了不可否认的成功。然而，目前的理论和实验努力仍未得出确凿证据，证明在宏观尺度上观察量子现象的可能性是否存在根本限制。这个问题促使人们进行了多项实验，以产生光或物质中大量子态的量子叠加。我们报告了利用纠缠见证者揭示的单个光子与晶体中冻结的数十亿个离子的原子系综之间的量子关联的观测结果。该态的物质部分涉及由几十种原子激发组成的两个宏观上可区分的固态分量的叠加。假设时间顺序无关紧要，我们的实验间接展示了光与物质的微观-宏观纠缠。我们的方法利用了量子存储技术，可用于其他系统以扩大物质中量子叠加的规模。
