We propose a multi-particle ‘which-path’ gedanken experiment with a quantum detector. Contrary to conventional ‘which-path’ experiments, the detector maintains its quantum state during interactions with the particles. We show how such interactions can create an interference pattern that vanishes on average, as in conventional ‘which-path’ schemes, but contains hidden many-body quantum correlations. Measuring the state of the quantum detector projects the joint-particle wavefunction into highly entangled states, such as GHZ’s. Conversely, measuring the particles projects the detector wavefunction into desired states, such as Schrodinger-cat or GKP states for a harmonic-oscillator detector, e.g., a photonic cavity. Our work thus opens a new path to the creation and exploration of many-body quantum correlations in systems not often associated with these phenomena, such as atoms in waveguide QED and free electrons in transmission electron microscopy.

中文翻译：

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通过 'which-path' 信息进行多体纠缠


我们提出了一个使用量子探测器的多粒子 'which-path' gedanken 实验。与传统的“哪个路径”实验相反，探测器在与粒子相互作用期间保持其量子态。我们展示了这种相互作用如何产生平均消失的干涉图案，就像传统的 “which-path” 方案一样，但包含隐藏的多体量子相关性。测量量子探测器的状态会将联合粒子波函数投影到高度纠缠的状态，例如 GHZ 的状态。相反，测量粒子会将探测器波函数投影到所需状态，例如谐振探测器的薛定谔 cat 或 GKP 状态，例如光子腔。因此，我们的工作为在通常与这些现象无关的系统中创建和探索多体量子相关性开辟了一条新途径，例如波导 QED 中的原子和透射电子显微镜中的自由电子。