论文标题
通过量子时间域干涉法对量子相关的无背光测量
Backaction-free measurement of quantum correlations via quantum time-domain interferometry
论文作者
论文摘要
时间域干涉法（TDI）是一种探测凝结物质系统中粒子之间的时空相关性的方法。将TDI应用于量子系统提出了一个一般问题，是否可以可靠地测量两次相关性，而不会对测量反动度不利影响到系统的动力学上。在这里，我们表明，最近开发的TDI（QTDI）的量子版本确实可以访问而无需背部的完整量子机械两次相关。我们进一步将QTDI推广到弱经典连续模式相干输入状态，从而减轻了对单光子输入字段的需求。最后，我们通过将时空相关性分为两个部分来解释我们的结果。虽然第一个与投影测量值相关，因此对背部不敏感，但我们确定了第二个贡献是由探测的目标系统状态的相干性能引起的，因此它被系统上的测量结果扰动甚至破坏。
Time-domain interferometry (TDI) is a method to probe space-time correlations among particles in condensed matter systems. Applying TDI to quantum systems raises the general question, whether two-time correlations can be reliably measured without adverse impact of the measurement backaction onto the dynamics of the system. Here, we show that a recently developed quantum version of TDI (QTDI) indeed can access the full quantum-mechanical two-time correlations without backaction. We further generalize QTDI to weak classical continuous-mode coherent input states, alleviating the need for single-photon input fields. Finally, we interpret our results by splitting the space-time correlations into two parts. While the first one is associated to projective measurements and thus insensitive to backaction, we identify the second contribution as arising from the coherence properties of the state of the probed target system, such that it is perturbed or even destroyed by measurements on the system.
