Tom Sawyer

I have a question about the Heisenburg Uncertainty Principle.

As I understand it, it states that we can't ever know the values we're dealing with completely, and there will always be this element of uncertainty that must be factored into any equation dealing with quantum matters and the like. In another thread, someone posted that this meant that there could be fluctuations in a void to produce effects without a cause since there is no true "void" when the Uncertainty Principle is factored in.

That doesn't make a lot of sense to me. I had always thought that this principle meant that we could not know anything to a 100% certainty, not that that certainty doesn't exist. My question is is this principle just a mathematical necessity needed to deal with the problem that our measurements will always be slightly off due to the fact that we cannot measure to a 100% certainty, or is it something that actually exists outside of our measurements and even voids are only void within a degree of error instead of truly void?

Godot

Well Tommy, you might find some answers from a similar discussion in another post here.

The UP basically says that the process of measuring alters what is really happening. This holds true regardless of the refinement of the tool being used; the invasive act necessitates a change. Sorry.

Tom Sawyer

I understand that the process of measurement affects the results and we cannot know two variables, such as position and momentum at the same time.

My question really revolves around the question of whether the Uncertainty Principle applies when no one is measuring it. The post that raised this question stated something along the lines of that the Big Bang could have occured due to fluctuations in the void that produced an effect without a prior cause, since it was never a "true" void, since the Uncertainty Principle prevents such a thing from being. There was no one observing or taking measurements at this time, so I thought that the principle would not apply, yet the gist of the post was that it is still factored in to whatever happened. I guess that my question could be refined to ask, if the Uncertainty Principle only applies when measurements and observation is taking place, how is it relevant in a situation like this when there was no observation occuring?

SULPHUR

Reminds me of the of "random walks" theory when dealing with meandering rivers.

Wounded King

Its hard to say if anything applies to things which arent observed, after all we have yet to see anything which is unobserved . As I understand it the uncertainty principle does not require an observe to operate, the role of the observer (whatever observer may mean in this context) is more important in terms of collapsing the eigenstate of the observed particle into one particular state. The vacuum fluctuations mentioned do not require observation as they are a result of the probablilistic distribution of potential particles.

Of course I am a biologist, so this could just be so much half understood popular sci/sci fi bobbins.

NumberTenOx

Tom, it's not just a measurement problem.

Your view (held by Einstein) is that there are "hidden variables" that exactly describe particle motion. If we could just somehow find a way to "look" without disturbing the system, we could know everything about the particle fully.

This view has been proven false. There are no hidden variables, the interaction between observation and reality is more fundamental. Google "Bell's Inequality" and "nonlocality". However there are still open questions about the role of the observer in determining the outcome of events.

Vacuum fluctuations are also real and measurable. The real vacuum is seething with activity, particles spontaneously created and destroyed underneath the limit of the Uncertainty Principle.

One theory - inflation - states that the universe was created as a result of a quantum fluctuation in a "false vacuum", an extremely energetic state. However, this presupposes the existence of a patch of false vacuum. It's one step closer to creation, yet it's not a complete solution. Although it may remove the need for a "first cause", it still needs the environment for the first cause to exist.

DBrant

I'm not sure any of us could actually even imagine a "true" void. Just because a volume of space does not contain any matter does not make it truly void.

According to quantum physics, the wave function for every particle stretches off into infinity, meaning that for every point in the universe, there is a small probability of finding every particle that exists!

I suppose that a "true void" might be a block of space through which no quantum wave function intersects. But we can never find something like that in this universe.

Furthermore, there is quantum electrodynamics, which introduces virtual photons to give a quantum explanation for the classical electromagnetic field. These virtual photons are actually particle-antiparticle pairs that blink in and out of existence in less than Planck time. So, basically, they violate the laws of conservation, but no one is fast enough to catch them in the act.

Wounded King

On the point about creating a space within which no waveforms can exist. I shall quote a post I had up on a different thread.

Any here feel like having a crack at it?

NialScorva

Also keep in mind that the UP says there are pairs that together cannot be measured perfectly, such as position/momentum and energy/time. It doesn't strictly say that you cannot know something with nearly 100% certainty, only that there is another aspect that you'd have to sacrifice having *any* knowledge about.

Wounded King

As Douglas Adams would have it

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