Wu Kang-Da, Yuan Yuan, Xiang Guo-Yong, Li Chuan-Feng, Guo Guang-Can, Perarnau-Llobet Martí
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, People's Republic of China.
CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, People's Republic of China.
Sci Adv. 2019 Mar 1;5(3):eaav4944. doi: 10.1126/sciadv.aav4944. eCollection 2019 Mar.
In quantum thermodynamics, the standard approach to estimating work fluctuations in unitary processes is based on two projective measurements, one performed at the beginning of the process and one at the end. The first measurement destroys any initial coherence in the energy basis, thus preventing later interference effects. To decrease this back action, a scheme based on collective measurements has been proposed by Perarnau-Llobet . Here, we report its experimental implementation in an optical system. The experiment consists of a deterministic collective measurement on two identically prepared qubit states, encoded in the polarization and path degree of a single photon. The standard two-projective measurement approach is also experimentally realized for comparison. Our results show the potential of collective schemes to decrease the back action of projective measurements, and capture subtle effects arising from quantum coherence.
在量子热力学中，估计幺正过程中功涨落的标准方法基于两次投影测量，一次在过程开始时进行，一次在结束时进行。第一次测量会破坏能量基中的任何初始相干性，从而防止后续的干涉效应。为了减少这种反作用，佩拉诺 - 洛贝特提出了一种基于集体测量的方案。在此，我们报告其在光学系统中的实验实现。该实验包括对两个相同制备的量子比特态进行确定性集体测量，这些量子比特态编码在单个光子的偏振和路径自由度中。为了进行比较，标准的两次投影测量方法也通过实验实现。我们的结果表明集体测量方案在减少投影测量反作用方面的潜力，并捕捉到由量子相干性产生的微妙效应。
