More than half a century ago, Werner Heisenberg proposed an "electron microscope" which would find both the momentum and position of a subatomic particle- impossible in quantum physics. The process is simple, an electron is fired at an particle and then reflects back to a detector. The reason this doesnt violate quantum mechanics is because the uncertainty in momentum is increased by the electron "hitting" the particle and therefore changing its momentum.

My question is: Would it be possible to fire an electron which counters the effects of the previous electron, therefore turning the particle back to its original state?

Please tell me what laws of prohibit this

Black hole

lucid, this is for physicists. get out

If I spin around the speed of light IL gain mass and create my own gravity. Like your mom.

I'm -10 kg, woah, hey, get away from me!

theoretically
its also theoretically possible to put a broken glass back together by reversing the angle and velocities of every atom that was once in the glass.

aand...

That is just my best answer, dunno if it helps

No it's not.

I mean, yeah, you can do that, but it's unstable and will crumble 2 seconds after regathering.

Like Yugoslavia?

LOLLLLLLLLLLLLLLLLLLLL ^

Can i please get an answer that does not violate the unceartinty principle? i want to know why its NOT possible.

I am not sure that I understand your question right, but I'll give it a try.

Yes, it is of course possible that with a second electron you could revert the particle to its original state, but the likelihood is extremly small (because you neither now the state of the particle nor of the first electron in the beginning, see uncertainty principle). But even if it happens you don't know for sure it happens, there is just a likelihood for that. You can't measure if it happened, cause any measurement affects the system and alters its state.

To me it seems you don't quite understand the uncertainty principle. If you want to try to understand it, you need to understand what "measuring/observing" means. When you measure something, you usually send a wave (electromagnetic wave like light or magnetic field, or a particle (wave)) to a particle. The wave changes the state of the thing you want to observe, therefore the act of observing the state of a particle changes the particles state.

Due to the uncertainty principle, you can't control with perfect precision the momentum and position of the electron you want to fire. The more precisely you control the position at time t, the less control you can have over the momentum.

Therefore, you can't choose to return a particle to its original state by firing an electron at it, because you have no guarantee that the electron will have the exact momentum and position that you want it to have.

http://physicsandphysicists.blogspot.com/2006/11/misconception-of-heisenberg-uncertainty.html

find both the momentum and position of a subatomic particle- impossible in quantum physics.

Heisenberg postulated in his Uncertainty principle:

*[..] is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle known as complementary variables, such as position x and momentum p, can be known simultaneously.* [Wikipedia]

"I am the one who knocks." -Heisenberg

"Yeah bitch! Science!" -Heisenberg's lab assistant

@neovim & jz

Would it not be possible to fire a number of electons with the same energy where if two hit from an opposite side, the atom is reverted to its original state. The chance of this happening is very small, but it still can happen.

@Ranek

Yes yes i know im sorry i explained it so badly but can you just answer the question

Well the uncertainty principle does not only state that you can't know both the impulse and location of a particle, but it also states you can't know the exact energy of a particle at a certain time. Think of it as resolution problem, you just can't measure it 100% accurately. If you know the energy than you have some uncertainty on the time scale.

With that information you need to think of it this way I think:

Your particle is at a fixed location (it can move, but we say the observer sits on the particle), so you don't know its impulse. The two electrons you need will have a fixed energy, therefore you can't know their position in spacetime exactly. So if you are firing them you only have a probability that they will mirror each other, but you never can be certain.

Let alone the point that even if you have an electron with a fixed energy, you can't be sure its energy will not change. For example pick a fixed point in space. The uncertainty principle will then tell you you can't know its energy, for example cause a particle and anti-particle appear out of nowhere (even in a vacuum). The electron might interfere with them, so you never can tell 100% if the energy of the electron stays the same. And you can't measure if those particles appear, cause your measurement will interfere with the electron as well.

Put that all together, and you will see that for your situation you can just speak with probabilities. And the probability that what you want will happen is extremly low - and you never can know if it actually happens.

(not sure my thoughts are right, quantum mechanics is a bitch :P)

what is the complimentary variable for the energy of a particle?

It's energy and time.

It's something that appears in the Math, and is related to the traditional form for the equation (position and momentum). One of the postulates of QM is that all observables have an operator. Energy, Momentum, and Position all have operators, but time does not. It means that the time-energy relationship is a bit "weird" (for lack of a better word).

Thinking about position vs momentum makes a lot more sense.

Edited 4/10/2015 21:27:34

thank you for answering the question and not raging about what an idiot i am

No problem. When dealing with Quantum Mechanics, I regularly feel like an idiot myself.

(by the way, I meant to say "It's energy and time" in my last post, not "It's energy in time")

Edited 4/10/2015 22:44:12