National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan and Department of Physics, School of Science, Federal University of Technology, P. M. B. 1526, Owerri, Imo State 460001, Nigeria.
National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan.
Phys Rev Lett. 2014 Jun 13;112(23):233602. doi: 10.1103/PhysRevLett.112.233602.
We introduce a theoretical framework for single-shot phase contrast imaging (PCI) measurements of spinor Bose-Einstein condensates (BECs). Our model allows for the simple calculation of the quantum backaction resulting from the measurement, and the amount of information that is read out. We find that there is an optimum time Gτ ∼ 1/N for the light-matter interaction (G is the ac Stark shift frequency, N is the number of particles in the BEC), where the maximum amount of information can be read out from the BEC. A universal information-disturbance tradeoff law ε(F)ε(G) ∝ 1/N(2) is found where ε(F) is the amount of backaction and ε(G) is the estimation error. The PCI measurement can also be found to be a direct probe of the quantum fluctuations of the BEC, via the noise of the PCI signal.
我们提出了一种用于单-shot 相位对比成像（PCI）测量旋量玻色-爱因斯坦凝聚（BEC）的理论框架。我们的模型允许简单地计算测量引起的量子反作用，以及读出的信息量。我们发现，在光物质相互作用的最佳时间 Gτ∼1/N 处（G 是交流斯塔克位移频率，N 是 BEC 中的粒子数），可以从 BEC 中读出最大信息量。我们发现了一个普遍的信息-干扰权衡定律 ε(F)ε(G)∝1/N(2)，其中 ε(F)是反作用的量，ε(G)是估计误差。通过 PCI 信号的噪声，我们还发现 PCI 测量可以直接探测 BEC 的量子涨落。
