终于完成了8月份这一期科普。给中学生讲解量子物理和基本粒子，很挑战。
摘录一篇。
跨越200多年的双缝试验
海上云 (2018-08-23 11:36:00) 评论 (21)终于完成了8月份这一期科普。给中学生讲解量子物理和基本粒子，很挑战。
摘录一篇。
海外博客
跨越200多年的双缝试验
海上云 发表评论于
回复 '陌路独行' 的评论 : 谢谢陌路兄的讨论，让大家对这个实验有更深入的理解。
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.
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.
陌路独行 发表评论于
我想请教的是：有没有人做过“发射”单个电子，通过双缝实验中的两个被分别遮挡了的“单缝”，得到一个叠加图案，与发射单个电子的双缝实验得到的图案，互相比较，排除单缝衍射叠加的可能，进而得出“单个电子也会自己干涉自己”的结论？
陌路独行 发表评论于
再次感谢“海上云”的回复，我看了那篇论文，似乎实验设定也是使用的“电子束”吧？
海上云 发表评论于
回复 '陌路独行' 的评论 : 谢谢讨论。文章里说到的bach 2013年的论文，提到了单电子单缝的结果。
Controlled double-slit electron diffraction
Roger Bach, Damian Pope, Sy-Hwang Liou, Herman Batelaan
Controlled double-slit electron diffraction
Roger Bach, Damian Pope, Sy-Hwang Liou, Herman Batelaan
陌路独行 发表评论于
多谢“海上云”的回复！
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。
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。
海上云 发表评论于
回复 '陌路独行' 的评论 : 所有的双缝试验第一步都是做两个单缝的试验。https://goo.gl/images/8Djth8
陌路独行 发表评论于
我对于量子是彻头彻尾的外行，但是从逻辑的角度，这个实验还是有缺陷的：有没有人用那个成功得到双缝干涉实验的设备，每次遮住一条缝隙，分别做两次做单光子/电子衍射实验，得到两次单缝衍射的叠加图案，然后比较结果？
沧海桑田2100 发表评论于
今后应该还会有更深的突破，逐步揭开世界的本质。
rp2002 发表评论于
双缝（凤）？
云本无心 发表评论于
无解的，像用文字表达音乐,最终是白费劲
海上云 发表评论于
海上云 2018-08-23 19:33:00
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。
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。
LingYuan 发表评论于
云兄好 你的记忆力真好，还记得我呢。
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。
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。
海上云 发表评论于
回复 'polar_bear' 的评论 :
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。
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。
海上云 发表评论于
回复 'LingYuan' 的评论 : 凌远兄好，好久不见。是的，量子世界因为尺度小，是有其“飘忽不定的，是模棱两可”的特性。从这一点上来说，是和人的精神世界有类似性。
polar_bear 发表评论于
其实，无论量子世界还是天文宏观世界，你要是大样本观察的话，都是波粒二象的，单个就是粒，整体就是波
polar_bear 发表评论于
问个简单问题：一个水分子的传播是以什么形式进行的呢？
simplyu 发表评论于
杨氏双缝干涉，都说了很黄，你还让我说
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？
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？
LingYuan 发表评论于
人有精神世界和物质世界。精神世界是飘忽不定的，是模棱两可的。物质世界是确定的，唯一的。量子世界表现的规律就是人精神世界的规律。人的行为也受外界观察的影响。有没有人看着，人的行为是不一样的。
LingYuan 发表评论于
杨贵妃搞同性恋， 后半句肯定是"荒唐"
beaglegirl 发表评论于
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？
simplyu 发表评论于
让我想起念书时流行的黄色歇后语，杨贵妃搞同性恋
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