Solution to uncertainty principle

[CyberShot]

We all know that you can supposedly never know the exact position and momentum of a particle, because the very act of measuring disturbs it.

Now, why can't we have two particles that start out and evolve the same exact way but separately and, using one of them as a dummy, perturb it, extract the momentum/position, and then use that information to describe the evolution of the undisturbed other?

Quantum theory is a provisional theory and is NOT the final answer; even Schrodinger and Dirac believed this.

 

[Fredrik]

Your question is very similar to the one asked in this thread, so you should start there.

 

[jtbell]

Now, why can't we have two particles that start out and evolve the same exact way but separately and, using one of them as a dummy, perturb it, extract the momentum/position, and then use that information to describe the evolution of the undisturbed other?

If you or anybody else can repeatably prepare two particles in such a way that at a later time both of them can be measured to have the same position and momentum, I guarantee that it will earn a Nobel Prize.

 

[StevieTNZ]

Can two particles have the same position? Wouldn't they overlap each other? Logic...

 

[CyberShot]

If you or anybody else can repeatably prepare two particles in such a way that at a later time both of them can be measured to have the same position and momentum, I guarantee that it will earn a Nobel Prize.

I was merely trying to suggest the that the Heisenberg principle does not apply in theory, only when it comes to practice. Surely, the sensible person would agree that just because we don't have precise technologies to measure observables, doesn't mean that they have to be quantum mechanically fuzzy or blotchy in nature. Einstein would've agreed. That's why he felt QM to be a temporary make-do, until we get the right picture.

Can two particles have the same position? Wouldn't they overlap each other? Logic...

They are not conservative, in that they don't have to the travel the same path.

 

[StevieTNZ]

I would think that two particles wouldn't be able to occupy the same space. No matter what path they traveled to get to that place.

 

[Matterwave]

I was merely trying to suggest the that the Heisenberg principle does not apply in theory, only when it comes to practice. Surely, the sensible person would agree that just because we don't have precise technologies to measure observables, doesn't mean that they have to be quantum mechanically fuzzy or blotchy in nature. Einstein would've agreed. That's why he felt QM to be a temporary make-do, until we get the right picture.



They are not conservative, in that they don't have to the travel the same path.

The Heisenberg Uncertainty principle is not a restriction on measurement abilities, but a theoretical absolute limit on what we can actually know about a quantum system. The popular misconception that it deals with some kind of limits due to measurements messing with the system is not quite right.

 

[mehul ahir]

sir please tell me can we ever enable toknow both the things simulteniously position and velocity ?
and from according to quantum gravity it is came toknow that big bang is justnot bigbang originally but it is bigbounce universe back and forth continuously but it states that we can't know any thing about the previous uni. is it right?if it is right then why please reply me via email my address is mehul_dangar9@yahoo.com

 

[_PJ_]

We all know that you can supposedly never know the exact position and momentum of a particle, because the very act of measuring disturbs it.

Now, why can't we have two particles that start out and evolve the same exact way but separately and, using one of them as a dummy, perturb it, extract the momentum/position, and then use that information to describe the evolution of the undisturbed other?

Quantum theory is a provisional theory and is NOT the final answer; even Schrodinger and Dirac believed this.

If the two are created from the same system, they are inherently entangled. Measuring the momentum or position of one will then define instantaneously, the momentum/position of the other.

For example, Particle A and B start off in superposition states.
If we measure the momentum (p1) of A, the velocity of A (v1) becomes largely uncertain.
At the instant of decoherence for A, the state of B also becomes definite in terms of its momentum (p2), leading to a large uncertainy in particle B's velocity (v2).

It was precisely this that Einstein referred to as "spooky action at a distance" and was pretty much the final nail in the coffin lid for Einstein (with Podolsky & Rosen) to concede 'defeat' that the Copenhagen interpretation of Quantum theory was correct and more complete than EPR could believe.

Note that the idea you propose also assumes a definite history, that the particles "start and evolve in the same way", since at the start opf their life, prior to any observation, the particles have no definite quantum identity, this is also problematic.

I was merely trying to suggest the that the Heisenberg principle does not apply in theory, only when it comes to practice. Surely, the sensible person would agree that just because we don't have precise technologies to measure observables, doesn't mean that they have to be quantum mechanically fuzzy or blotchy in nature. Einstein would've agreed. That's why he felt QM to be a temporary make-do, until we get the right picture.

This was why Einstein was also wrong. Heisenberg IS applicable in practice, Alain Aspect's experiments to test Bell's Theorum have shown this without a doubt.
The uncertainty relation doesn't indicaste to a lack of measuring accuracy, but a limit to what is KNOWABLE.

 

[yoda jedi]

I was merely trying to suggest the that the Heisenberg principle does not apply in theory, only when it comes to practice. Surely, the sensible person would agree that just because we don't have precise technologies to measure observables, doesn't mean that they have to be quantum mechanically fuzzy or blotchy in nature. Einstein would've agreed. That's why he felt QM to be a temporary make-do, until we get the right picture.

Read:
Doubt regarding uncertainty principle.
https://www.physicsforums.com/showthread.php?t=472818

that is known as Two Vector formulation of Quantum Mechanics.

http://www.tau.ac.il/~yakir/yahp/yh30

...A description of quantum systems at the time interval between two successive measurements is presented. Two wave functions, the first preselected by the initial measurement and the second post-selected by the final measurement describe quantum systems at a single time...

and

http://arxiv.org/PS_cache/arxiv/pdf/1002/1002.3139v3.pdf

...A quantum state is not discernible by means of a single replica, but can be reconstructed only by performing many measurements on identically prepared systems...