Schrödinger’s famous Gedankenexperiment has inspired multiple generations of physicists to think about apparent paradoxes that arise when the logic of quantum physics is applied to macroscopic objects. The development of quantum technologies enabled us to produce physical analogues of Schrödinger’s cats, such as superpositions of macroscopically distinct states as well as entangled states of microscopic and macroscopic entities. Here we take one step further and prepare an optical state which, in Schrödinger’s language, is equivalent to a superposition of two cats, one of which is dead and the other alive, but it is not known in which state each individual cat is. Specifically, the alive and dead states are, respectively, the displaced single photon and displaced vacuum (coherent state), with the magnitude of displacement being on a scale of ${10}^8$ photons. These two states have significantly different photon statistics and are therefore macroscopically distinguishable.

中文翻译：

---

宏观上截然不同的光态的纠缠

Schrödinger著名的Gedanken实验激发了多代物理学家思考将量子物理学的逻辑应用于宏观物体时出现的明显悖论。量子技术的发展使我们能够生产薛定ding猫的物理类似物，例如宏观不同状态的叠加以及微观和宏观实体的纠缠状态。在这里，我们进一步迈出了一步，并准备了一种光学状态，按照薛定'的语言，该状态相当于两只猫的叠加，其中一只死了而另一只还活着，但是不知道每只猫处于哪种状态。具体来说，活态和死态分别是位移的单光子和位移的真空（相干态），位移的大小为${10}^8$光子。这两个状态具有明显不同的光子统计量，因此在宏观上是可区分的。