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If you take a laser and shine it at a wall with two holes in it, you have the famous double slit experiment
如果你用激光照射一面有两个洞的墙，你就会有一个著名的双缝实验
- where waves coming through two slits interfere with each other to be bright in some places on the wall, and dark in others.
--穿过两个缝的波相互干扰，在墙上的一些地方是明亮的，而在另一些地方是黑暗的。
And this works with quantum particles, too, since they behave in wave-like ways: send a cat towards the slits, and it’ll show up at a point on the wall.
这也适用于量子粒子，因为它们的行为像波浪一样：把一只猫送到缝隙里，它就会出现在墙上的某个点上。
Send a bunch of cats, and their accumulation reveals the same interference pattern as a light wave .
发送一群猫，它们的累积显示出与光波相同的干涉图案。
Now imagine you add another, competing double slit experiment, with another cat, that shares one of the slits with the first setup.
现在，想象你添加了另一个竞争性的双缝实验，另一只猫与第一个设置共享一个缝。
Of course, if you send the second cat over and over towards these two slits , the points where it hits the wall will give a similar interference pattern.
当然，如果你把第二只猫一遍又一遍地送到这两个狭缝里，它撞到墙上的点会给出类似的干涉图案。
And at this point here for one cat, and this point here for the other, those cats never show up, no matter how many times you send them through the slits.
在这里对一只猫来说，在这里对另一只猫来说，这些猫永远不会出现，无论你让它们多少次穿过缝隙。
Their wavelike behavior causes what’s called “destructive interference”; if cats were light, these points would be in cat-darkness.
它们的波动行为造成了所谓的“破坏性干涉”；如果猫是光，这些点就会处于猫的黑暗中。
But weird things happen if you send both cats at their double slits at the same time.
但是，如果你同时把两只猫放在双缝里，就会发生奇怪的事情。
The top cat goes through the top and middle slits and then towards the wall, and the bottom cat goes through the bottom and middle slits and then towards the wall;
顶部的猫穿过顶部和中间的缝隙，然后朝向墙壁，底部的猫穿过底部和中间的缝隙，然后朝向墙壁；
nd things would again go as expected, of course, except that the cats get in each others’ way going through the middle slit.
当然，一切都会像预期的那样进行，只不过猫咪们在穿过中间的缝隙时会互相阻碍。
Maybe the slit’s too small for two cats to fit through simultaneously, or maybe, yeah!
也许这个缝隙太小了，两只猫无法同时通过，或者，也可能，是的！
Maybe one cat is actually made of antimatter so if both go through the middle slit, they annihilate each other and never make it to the wall.
也许有一只猫实际上是由反物质组成的，所以如果两只猫都穿过中间的缝隙，它们就会互相湮灭，永远也无法到达墙壁。
Either way, the situation is now this:
无论哪种方式，现在的情况都是这样的：
the cats traverse the slits in a quantum superposition of top cat top/bottom cat middle, top cat top/bottom cat bottom, and top cat middle/bottom cat bottom.
猫穿过缝隙的时候，会形成一个量子叠加，上面的猫在上面/下面的猫中间，上面的猫在上面/下面的猫底部，上面的猫在上面/下面的猫底部。
There’s no “both cats in the middle” in the superposition, since the cats can’t traverse the middle slit together.
叠加中没有“两只猫都在中间”，因为这两只猫不能一起穿过中间的缝隙。
And since the superposition is missing the “both cats in the middle” option, the interference patterns change and it’s possible for the cats to end up in the places on the wall where before there was cat darkness.
由于叠加缺少了“两只猫都在中间”的选项，干涉图案发生了变化，猫有可能最终落到墙上没有猫的地方。
This isn’t at all surprising for waves - I mean, different amounts of wave coming through the slits means a different interference pattern.
这对波来说一点也不令人惊讶--我的意思是，不同数量的波通过缝隙意味着不同的干涉模式。
But there’s something weird about this when particles are involved.
但是当涉及到粒子的时候，这就有些奇怪了。
To see why, remember that individually, the cat darkness arose because the cat’s wave-particle superposition went through both slits and interfered with itself to result in zero probability of the cat ending up there.
要了解原因，请单独记住，猫咪黑暗的出现是因为猫咪的波粒叠加穿过了两个狭缝，并干扰了自己，导致猫咪最终到达那里的可能性为零。
So if the bottom cat DOES end up there, it must not have been able to interfere with itself, so it must not have gone through both slits, so there must have been something blocking one - the other cat, in the middle.
因此，如果底部的猫确实到了那里，它肯定不能干扰自己，所以它肯定没有穿过两个缝隙，所以肯定有什么东西挡住了其中一只-另一只猫，在中间。
And if the top cat ends up in its previously cat-free spot, then it must not have gone through both slits either - the bottom cat must have been blocking the middle slit.
如果顶端的猫最终落在了之前没有猫的地方，那么它肯定也没有穿过两个缝隙--底部的猫一定是挡住了中间的缝隙。
This wouldn’t be a problem, except that when you actually do this experiment , some of the time BOTH cats end up in the previously cat-free spots.
这不是问题，只是当你实际做这个实验时，有时两只猫最终都会出现在以前没有猫的地方。
And we know they can’t both have gone through the middle slit, because they would have annihilated each other
我们知道它们不可能都穿过中间的狭缝，因为它们会相互湮灭
- so each cat must have been blocked from going through the middle slit by the other cat having gone through the middle slit, simultaneously.
所以每只猫都被另一只同时从中间缝穿过的猫挡住了。
Which of course seems impossible, and is why this situation has been called a paradox .
当然，这似乎是不可能的，这就是为什么这种情况被称为悖论。
And it’s certainly thought-provoking if you like to think about local realism or contextuality or weak measurement values or the interaction between classical logic and quantum mechanics.
如果你喜欢思考局部实在论，情境性，弱测量值，或者经典逻辑和量子力学之间的相互作用，这当然是发人深省的。
But it’s not really that surprising, as long as you believe that quantum particles can be in superpositions (which happens all the time and has been incredibly well experimentally confirmed).
但这并不令人惊讶，只要你相信量子粒子可以叠加(这种情况一直都在发生，并且已经得到了令人难以置信的良好的实验证实)。
As we said earlier, the two cats pass through the slits in the superposition “top middle” plus “middle bottom” plus “top bottom”,
就像我们之前说的，两只猫穿过“顶部中间”+“中间底部”+“顶部底部”叠加的缝隙，
which include both apparently necessary “blockages” of the middle slit by one cat or the other,
其中包括由一只猫或另一只猫对中间缝隙明显必要的“堵塞”，
and it’s this superposition that results in the changed interference pattern that allows for the possibility that both cats simultaneously end up in the previously cat-dark locations.
正是这种叠加导致了干扰模式的改变，从而有可能两只猫同时出现在以前猫是黑暗的地方。
If all of this seems a bit weird - yeah, it is!
如果这一切看起来有点怪异-是的，就是这样！
But it’s worth remembering that weirdness and paradox are not one and the same .
但值得记住的是，怪异和悖论并不是一回事。
And the quantum cat/antimatter-cat double double-slit experiment is fully consistent with the predictions and experimental results of quantum mechanics.
量子猫/反物质-猫双双缝实验与量子力学的预测和实验结果完全一致。
Sometimes the universe is just weird!
有时候宇宙就是很奇怪！
