Please explain to me quantum entanglement.. and can we “ hypothetically “ build a quantum entangled cameras or some sort of optical device one we can observe on and them put this device in a space shuttle or smt then we can observe events in time ?
Let’s just say this device is 1 light years away but it’s entangled with a device here on earth so events will reach us 1 in 1 year or just in time?
In: Physics
This is hard to ELI5 because some of these concepts don’t have an ELIPhD yet. Quantum Entanglement is a topic at the fringe of human knowledge. The most well-trained people in Physics are still trying to answer these questions. If they don’t know the answer, there’s not an ELI5.
We know what it *is* enough.
Quantum Physics deals with special particles that are even smaller than the parts of an atom. Just like atomic particles do weird things, these do weird things. So weird we argue they have their own special Physics.
Dealing with these particles is hard. We can’t see them. Even with a microscope. To visualize what we have to do, imagine a silly experiment. You’re in a room with no windows. To your east is a room you know has some balloons floating inside it. There is a cannon that will shoot a foam ball on the wall. You can get it to shoot the ball at any angle and velocity, thus you can make the ball hit any part of the other room.
This is actually enough to figure out where the balloons are! You can fire a ball at an angle, and if you don’t hear it hit a balloon, you know there are no balloons along that path. With the right tools, you can start forming a 3D image of the room and show where balloons aren’t, and it will get more and more likely you find where a balloon is. But, alas, if your ball hits the balloon, it’s going to get moved somewhere else. So you can only really figure out where a balloon *isn’t* and where a balloon *was*, though after you hit a balloon you can make some guesses where it may have went.
This is what it means to “observe” quantum particles. They’re so tiny that photons of light actually have an effect on them. So we “see” them by firing particles at where we know one is, and we observe how the particles reflect back, kind of like listening for a ball hitting the balloon. How the particles reflect back tell us about where the particle was and what it was doing. But it only works the one time. This is what’s meant by saying “observing” the particle changes it. It’s technically always changing, but in one specific moment we do a specific thing to find out what it was doing at that moment.
For “entanglement”, things get weird. We have figured out that, for reasons, two quantum particles can be “entangled”. That means whatever one is doing, the other is also doing. We still don’t fully understand this, but we understand it enough to figure out if it’s happening and to cause it to happen to some particles. What is really “weird” about entanglement is so far as far as we can tell, if you change one particle the other changes “instantaneously”.
Now, “instantaneously” is a crazy word in Physics. Normally when something happens in Physics, it happens “fast”. Like, if one object collides with another, it *seems* instantaneous that they react but in reality force is being transferred in nanoseconds and other tiny intervals.
This is, as far as we can tell, *instantaneous*. Zero time passes. And, more mysteriously, having more distance between entangled particles does NOT so far produce a measurable delay. That’s stupid exciting.
It leads us to think things like:
> can we “ hypothetically “ build a quantum entangled cameras or some sort of optical device
“Hypothetically” yes! If we could somehow make an image sensor consist solely of entangled particles, we could maybe find a way to use the particles where we are to form an image over *infinite* distances instantaneously. That’s still really hard! Remember, to observe particles we have to change them. And entanglement works 2-ways. And so far we’re very limited in how we can purposefully cause entanglement, or how far apart the particles can be, etc.
The problem is there are different degrees of “hypothetical” depending on how much we’d have to figure out to do it. For example, “useful nuclear fusion” is a small “hypothetical”. If we funded it with as much money as we spend on cryptocurrency, Physicists are pretty sure we could have it within 20 years. It’s just right now we’re choosing to spend an amount of money on it that leads the Physicists to estimate “never”.
If we call the distance from us to nuclear fusion like “500,000 miles”, the distance from us to some form of quantum camera is something like the distance from us to the next galaxy. We can’t comprehend how to get there. There’s too much to figure out. We’re not even sure if we CAN figure it out. But the possibilities are so exciting we’re willing to let people spend their entire lives trying to figure it out. Any breakthrough we make could cut that distance back down to something reachable. It’s just it’s hard to tell what you need to know when you don’t know what you don’t know.
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