看到有人分享这个 https://arxiv.org/abs/1902.05080 文章，然后心血来潮找了一些东西然后在这里标记一下以后看。

关于观察者的问题，我觉得这条评论其实说得挺好的，测量效应本质上和量子纠缠是相同的现象，下面引用部分：

The solution is that measurement and entanglement are the same physical phenomenon. Measurement is just entanglement extended to a macroscopic system through a process called "decoherence". The net result is that, when you do the math, you recover classical behavior by taking "slices" of the wave function (the mathematical operation is called a "trace").

I'm going hazard a guess that your next question is going to be: why do I not perceive myself to be in a superposition of states? And the answer is that you are not what you think you are. You think you are a human being, a classical physical object made of atoms, but you aren't. This is a very good approximation to the truth, but it is not the truth. The truth is that you (the thing engaged in this conversation) are a software process running on a human brain. You are a classical computing process, i.e. a process that can be emulated by a classical computing model like a Turing machine. The reason for this is that the kinds of things you do necessarily involves copying information (e.g. the process of reading this comment involves copying information from your computer into your brain) and quantum information cannot be copied. Only classical information can be copied. Your conscious awareness of the existence of physical processes is an emergent phenomenon of accumulating memories, i.e. copying information. Because of this you cannot become consciously aware of your quantum nature, and because of that you cannot demonstrate the quantum nature of any system (to yourself) unless it is isolated from you. You could in principle demonstrate the quantum nature of the rest of the universe if you could somehow isolate yourself from it, but that presents insurmountable practical difficulties.

一个经典意义上的“观察者”不能展现或者理解自身的量子性，作为维格纳的朋友，我无法理解自身的叠加状态，但这是因为“意识”是存在于经典意义上的计算过程上的，其本身具有逻辑上（而非物质意义上）的确定性和唯一性。

因此，尽管意识是和观察者联系在一起的，但是不能将意识神秘化或者特殊化，不能理解为有意识的生物的观察才能造成波函数的坍缩。

觉得其实还有好多应该好好搞明白的问题，再贴两个以前看到过的：

- 微观下的因果顺序被证明是模糊的
- 一个试图反驳哥本哈根诠释的思想实验和 hackernews 的评论，两个观察者可能会看到互相矛盾的事件？

有空再看想想......