The movable mask was placed behind the double-slit, see figure 1. The mask was moved from one side to the other (figure 2 top to bottom). Initially the majority of the electrons are blocked. As the mask is moved, slit 1 becomes partially, then fully open. When one slit is open, single- slit diffraction can be observed (P1 in figures 1(b) and 2). Feynman indicates this as the solid black curve P1 (figure 1(b)), which is just the central order of the single-slit diffraction pattern. Because of the finite separation of the mask and double-slit, weak double-slit diffraction can be seen in the negative first order of the single-slit diffraction pattern (see left edge of P1 in figure 2).
As the mask is moved further, more electrons can travel through both slits, changing the pattern from single-slit to double-slit diffraction. When the mask is centered on the double-slit, both slits are completely open and full double-slit diffraction can be observed (P12 in figures 1(c) and 2). In this position, interaction between the mask and the diffracting electrons is negligible. The edges of the mask are 2250 nm away from the center and would only affect diffraction orders greater than the 50th. The mask is then moved further and the reverse happens; double- slit diffraction changes back to single-slit diffraction (P2 in figures 1(b) and 2). Now, the single- slit diffraction pattern has a weak contribution of double-slit diffraction in its positive first order (see right edge of P2 in figure 2). (See supplementary movie 1 for more positions of the mask.)
Electron build-up patterns were recorded with the mask centered on the double-slit. The electron source’s intensity was reduced so that the electron detection rate in the pattern was about 1 Hz. At this rate and kinetic energy, the average distance between consecutive electrons was 2.3 × 10^6 m.
这篇文章的电子版在这里：http://iopscience.iop.org/article/10.1088/1367-2630/15/3/033018/pdf
下面三段文字，说明了滑动屏幕实验中包含了单缝的结果。而电子束的强度减到非常弱，可以认为电子是i一个个分开发射出来的。
The movable mask was placed behind the double-slit, see figure 1. The mask was moved from one side to the other (figure 2 top to bottom). Initially the majority of the electrons are blocked. As the mask is moved, slit 1 becomes partially, then fully open. When one slit is open, single- slit diffraction can be observed (P1 in figures 1(b) and 2). Feynman indicates this as the solid black curve P1 (figure 1(b)), which is just the central order of the single-slit diffraction pattern. Because of the finite separation of the mask and double-slit, weak double-slit diffraction can be seen in the negative first order of the single-slit diffraction pattern (see left edge of P1 in figure 2).
As the mask is moved further, more electrons can travel through both slits, changing the pattern from single-slit to double-slit diffraction. When the mask is centered on the double-slit, both slits are completely open and full double-slit diffraction can be observed (P12 in figures 1(c) and 2). In this position, interaction between the mask and the diffracting electrons is negligible. The edges of the mask are 2250 nm away from the center and would only affect diffraction orders greater than the 50th. The mask is then moved further and the reverse happens; double- slit diffraction changes back to single-slit diffraction (P2 in figures 1(b) and 2). Now, the single- slit diffraction pattern has a weak contribution of double-slit diffraction in its positive first order (see right edge of P2 in figure 2). (See supplementary movie 1 for more positions of the mask.)
Electron build-up patterns were recorded with the mask centered on the double-slit. The electron source’s intensity was reduced so that the electron detection rate in the pattern was about 1 Hz. At this rate and kinetic energy, the average distance between consecutive electrons was 2.3 × 10^6 m.
Controlled double-slit electron diffraction
Roger Bach, Damian Pope, Sy-Hwang Liou, Herman Batelaan
对“光束”和“电子束”的实验没有任何疑义，但是找不到“单个”光子或者“单个”电子做两次单缝实验得到的叠加结果。
回复 'LingYuan' 的评论 : 谢谢凌远兄。我这几年主要时间在写科普。我记得你写的诗和诗评呢，特别是评天端的诗。一晃差不多十年了。
量子世界一个基本特性是测不准的特性。随着对量子世界越来越多的认识，这种说法似乎值得商榷。因为说测不准的隐含之意是被测物是确定的 只是不能准确测出来。现在看来量子世界本身就是不确定的。
你的双缝实验科普写得很好，既有来龙又有去脉 条理清晰 深入浅出。从小小的双缝 把量子世界洞察得非常清晰。
水分子运动， 应该是布朗运动吧。
“大样本观察的话都是波粒二象的，单个就是粒，整体就是波“，波粒二象倒并不是按”单个／整体“来区分的。宏观物体的波动性很小，几乎不可察觉。而微观物体的波动、粒子特性都可观测到，但是受互补原理的限制，只能同时观察到其中之一，仿佛硬币的两面，只能看到一面。
beaglegirl 发表评论于 2018-08-23 16:14:36
simplyu：让我想起念书时流行的黄色歇后语，杨贵妃搞同性恋
--下半句是什么？
--下半句是什么？