Experimental violation of a Bell's inequality in time with weak measurement
Experimental violation of a Bell's inequality in time with weak measurement
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DOI：
10.1038/nphys1641
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发表时间：
2010-06-01
期刊：
影响因子：
19.6
通讯作者：
Korotkov, Alexander N.
中科院分区：
文献类型：
--
作者：
Palacios-Laloy, Agustin;Mallet, Francois;Korotkov, Alexander N.
两个纠缠和空间分离的量子二能级系统(TLSS)违反Bell不等式通常被认为是自然界不服从局域实在论的最突出的证明。在宏观系统貌似符合的宏观现实主义的不同但相关的假设下，莱格特和加格推导出了经历相干振荡并在连续时间被测量的单个自由度的类似不等。在这里，我们测试了这样一个“时间上的贝尔不等”，这应该被量子TLS打破。我们的TLS是一个超导量子电路，在这个电路中，Rabi振荡被连续地驱动，而它被连续和弱地测量。探测器输出的时间关联符合量子力学的预测，违反了莱格特-加尔格不等式五个标准差。
The violation of Bell inequalities with two entangled and spatially separated quantum two-level systems (TLSs) is often considered as the most prominent demonstration that nature does not obey local realism. Under different but related assumptions of macrorealism-which macroscopic systems plausibly fulfil-Leggett and Garg derived a similar inequality for a single degree of freedom undergoing coherent oscillations and being measured at successive times. Here, we test such a 'Bell's inequality in time', which should be violated by a quantum TLS. Our TLS is a superconducting quantum circuit in which Rabi oscillations are continuously driven while it is continuously and weakly measured. The time correlations present at the detector output agree with quantum-mechanical predictions and violate the Leggett-Garg inequality by five standard deviations.