An uncertanty in "Heisenberg's Uncertainty Principal".

Ok, I was watching a show about Star Trek, and this one scientist guy was saying something about how the transporters could not be built in real life because of Heisenberg;s Uncertainty Principal.

Now, I of course being the scientist I am started thinking about the problem.


Now, as I understand the basis of Heisenberg's Uncertainty Principal, is that you can not know both the Position and Momentum of a particle, you can know one or the other, but not both.


Now I started thinking, if you had a set of scanners, A and B and a computer C.

If you used A to find out the particles Position, and used B to find out it's Momentum, and sent that information to C, than would not the computer than know both the momentum and position of the particle?

Thusly getting around Heisenberg's principal?



Really like some of the more science oriented ATSers help on this, thanks.

Actually heisenberg's uncertainty principal has more to do with by the time you calculate it, even with a computer, the particle is moving so fast, it isnt there anymore, thus, it's difficult to do....you can know where it was, just not where it is now.....make sense?

[edit on 16-3-2006 by XphilesPhan]

Originally posted by iori_komei

If you used A to find out the particles Position, and used B to find out it's Momentum, and sent that information to C, than would not the computer than know both the momentum and position of the particle?

Thusly getting around Heisenberg's principal?

Really like some of the more science oriented ATSers help on this, thanks.

By measuring with A and finding the position, you alter its momentum, so that when B then measures the particle, it finds its momentum, but alter its speed.

So at anyone time , you can still only measure one of the two properties position/momentum.

You would find both a momentum and speed but they would be for two different times, rather than the same.

Trying to measure both at the same time wouldn't work because one of the measurements would always be slightly different time and position wise from the other, and then there is the inherent probaility wave of all the measurements involved.

Just a small inconvience that I'm sure someone someday will find a way around it.

They always find ways around things.

[edit on 16-3-2006 by d1k]

Originally posted by iori_komei
Now I started thinking, if you had a set of scanners, A and B and a computer C.

If you used A to find out the particles Position, and used B to find out it's Momentum, and sent that information to C, than would not the computer than know both the momentum and position of the particle?

The result at C would be just as uncertain as the result at A or B. If you combined the two measurements, the uncertainty in the position in measurement A means you can't be sure you are talking about the same particle in measurement B, where the position is better known.

I like the camera shutter analogy for the uncertainty principle. If you have a fast shutter taking a picture of an object moving very quickly, it is easy to see the position of the object, but it looks stationary (no momentum info). But if the camera shutter is set longer, the object looks smeared and the position hard to determine, but the smeared image shows motion and the more smearing, the more momentum the object has.

Its a bit simplistic, but it helps to illustrate the point.

Originally posted by d1k
Just a small inconvience that I'm sure someone someday will find a way around it.

They always find ways around things.

I dont think anyone will or has ever found a "way around" fundamental laws of physics

But back on topic the previous posters were correct, there would still be an inherent uncertainty in the calculation. You can still obtain a possible range of values for the momentum or position, but not its exact value.

-George

Originally posted by d1k
Just a small inconvience that I'm sure someone someday will find a way around it.

They always find ways around things.

Yeah, I hope they come up with the Heisenberg compensator as well. Maybe we just don't understand how to build one yet at the moment. It is no reason to say it is impossible.

Just a small inconvience that I'm sure someone someday will find a way around it.

They always find ways around things.

The Heisenberg Uncertainty Principle is better explained by saying that a particle does not possess the property of simultaneous precise momentum and position. It is not a quirk of annoying measuring devices.

Rob.

check this out

you want to find the position and momentum of a particle say, A at t=0,
you fire photons of 'known' energy at the particle, you detect the rebounded photons to determine accurately the position of A at t=0.

after a time T, you fire photons again, to determine the new position of A but the new position you obtain is not the position that the particle would have possesed if the first measureent had not been made. this is because the momentum of A had been altered by the first measurement. but if the photons had known energy (momentum) , isnt it possible to determine what the change in momentum due to the photon would have been, and use this result to compensate for the error in finding the new position, thus effectively determining both postn and mom of the particle at t=0....


the problem with this, is i think, that the momentum of the photons would have to be measured in the first place and only then can we do the necessary compensation... thus unc principle is a recursive law looping in around itself and i hate such laws

help me out here people

It simply shows that the writers of Star Trek iddn't hold PhDs in physics.

It's not usually a good idea to draw theories based on what you see or read or hear in a presentation designed for the public in general. Usually it's been watered down to the point where the big idea is gotten across but the details are not there. If you speculate on the Big Idea, you can end up in a morass.

We see this all the time here when people announce they have found errors in Einstein's equation (or various other equations.) What they have found, instead, is gaps in their understanding of the principle... not true errors in the principle.

Originally posted by iori_komei

Now I started thinking, if you had a set of scanners, A and B and a computer C.

If you used A to find out the particles Position, and used B to find out it's Momentum, and sent that information to C, than would not the computer than know both the momentum and position of the particle?

Thusly getting around Heisenberg's principal?

The short answer is - NO! And actually, this applies on the macro scale as well as the particle scale. And it comes down solely to the package of information that must be known for the momentum side of the "full meal deal". With momentum being dependent on the velocity of the object, and the velocity of the object being the derivative of the position, you must ALWAYS know more than one positional data point to derive the velocity, and therefore the momentum. So you are always using "dated" information. The minute you determine your momentum you have a number of the past.

The same holds true for a radar gun that buys you a ticket - it gets your positional data a couple of times - and both of those are expired information, and then calculates your velocity for the last expired positional point - and no longers knows where you are or what your velocity is...not even at the microsecond it took for it to determine your velocity. You are in the unknown again immediately.

[edit on 3-18-2006 by Valhall]

This is a study done by the USAF on Teleportation. This paper talks about why Heisenberg' uncertainty principal would hinder teleportation, and theories on how to overcome that through quantum entanglement. It also talks about telekenetic teleportation, which is a cool thing to hear from a scientific viewpoint.

My understandin of Heisenberg's uncertainty principal is simple. If you're calculating time or any other equation that carries numorous vairiables, if one of those vairables changes, then the whole equation could become void, because of the obvious trickle effect. It is general uncertainy because it is hard to keep an eye on all components of your experiement. AAC

The momentum of the quantum particles are changed by observing that particle. You need a photon to observe a quantum particle, like anything else.The photon has to bounce off of that particle and into the camera, eye, lense, whatever. If you think of it like two balls hitting each other, in order for us to see the particle, the ball has to bounce off of it, thereby transfering some of it's energy, and changing its momentum. as long as you are observing it's position, it's velocity will be different than it usually is.

Originally posted by Rasobasi420
The momentum of the quantum particles are changed by observing that particle. You need a photon to observe a quantum particle, like anything else.The photon has to bounce off of that particle and into the camera, eye, lense, whatever. If you think of it like two balls hitting each other, in order for us to see the particle, the ball has to bounce off of it, thereby transfering some of it's energy, and changing its momentum. as long as you are observing it's position, it's velocity will be different than it usually is.

But even if we had a non-intrusive method of measuring a particle's position, the Heisenberg uncertainty principal would still hold. It will always hold when one parameter needed to get the full data set is dependent on the time-derivative of another parameter needed for the full data set. In other words, we have only two independent variables (time and position) and the third required parameter is dependent on the first two.

I see, because the the quantum state of matter is so "uncertain", by that I mean particles bouncing in and out of existence, relying on probability to control their states, measuring anything at any particular time does little good because it won't be in that exact state again.

Originally posted by Rasobasi420
I see, because the the quantum state of matter is so "uncertain", by that I mean particles bouncing in and out of existence, relying on probability to control their states, measuring anything at any particular time does little good because it won't be in that exact state again.

what exactly does it mean for something to rely on probability? i mean, prob isnt a law, its not even mathematically sound... prob is like escapism... there must be some hidden variable or an undiscovered law that can explain the apparent randomness observed in quantum systems... declaring that such things are 'governed by probability' is like trying to shirk from findin the right description...

does probability mean that quantum events are random??? but what IS "random" ? how do you define it? everything must happen for a reason right?? how can the effect of a cause be just random???

Originally posted by off2_infinity

there must be some hidden variable or an undiscovered law that can explain the apparent randomness observed in quantum systems...

Very good point! We are only constrained by the knowledge envelope we are working within right now! No telling what tomorrow will bring!

Onward and upward!

The uncertainty principle was developed because light is not an exact medium. You know the length of things, but not EXACTLY. Heisenberg used less and less light in an attempt to get an exact measurement of an atom (or whatever), but any amount of light does not give an accurate view of the object as it reflects and refracts and gives uncertain readings. You could have 50 sensors connects to the original computer but you can't be certain that the lengths given will be accurate because it will only be an average of rough estimates.

scientists have found a way around this. it's called quantum entanglement. yes they have teleported things, including massive particles, exitons.