# Uncertainty vs Determinism

1. Nov 1, 2009

### A-wal

This wont be an in depth discussion because I've already got one of those going on in the relativity forum. Let me start by saying I hate the idea of the uncertainty principle! From what I understand it basically comes from the concept that waves can be thought of as particles and the chances of them doing something correspond to the dips and hills in a wave (can't remember the correct terminology). Either each particle has a chance of doing something rather than being predetermined to do it, or each particle knows what the others before and after have done and will do. I seems to me that the second explanation is more likely. After reading about action at a distance and how it's a real effect, not just something that's made to sound weirder than it really is. The two particles know about each other. Thoughts?

2. Nov 1, 2009

Staff Emeritus
Thoughts? How about "the universe is under no compulsion to arrange itself in a way that you like."

3. Nov 1, 2009

### A-wal

lol I was beginning to suspect as much. I just don't see how how one idea is more far-fetched than the other. They're both equally stupid, but apparently one's true so why can't the other be. Neither are as dumb as randomness!

4. Nov 1, 2009

### BigD

Why would you hate the uncertainty principle? Does it really matter that much if reality is not deterministic? And, as far as I know, quantum theory does not make determinism impossible, it just puts limits on what we can know.

5. Nov 2, 2009

### A-wal

I was under the impression that it's not just an inability to simultaneously measure position and velocity, but an actual property of the universe that it has a built in random element to it.

How exactly does action at a distance work anyway. I know that when a particle ejects two mini particles you can measure the polarity (forgive my wording) of one and force the wave function of the other to collapse, but how do you know this without measuring the second one?

And why can't this principle be used to send a signal (not literally) faster than the speed of light. You could use Morse code.

6. Nov 2, 2009

### TMFKAN64

If two particles are entangled in a certain way, if you measure the spin of one, you will know the spin of the other. You'd have to measure this one as well if you wanted to be sure, of course... but when people have done this, they have found that they always match.

Suppose I flip a coin here... and you immediately know if it was heads or tails. Does this really help me to tell you anything other than the state of my coin flip?

There is no known way to transmit useful information using entanglement.

7. Nov 2, 2009

### imiyakawa

Couldn't you somehow utilize the cosmic quantum eraser delayed choice thingy to communicate information, supposedly FTL, in binary?

All we'd need is to eliminate any form of decoherence (assuming the act of consciously observing the particle in the form of measurement doesn't endear its collapse) whilst measuring the photons at their source [impossible at the moment?], keeping a constant stream of photons heading towards the intended sender of information who communicates in binary by selective wavefunction collapsing. Then we have photons coming back the other way for dialogue. Due to non-locality, looking at this logically from my limited knowledge of quantum mechanics I don't see a reason why this wouldn't enable FTL communication.

But if this could work wouldn't this say that we can receive the message before the communication has even been sent by those on the other side? I guess we'd have to avoid reading the message before it was sent to avoid blowing up the universe. (Joking)

I'm basing this idea on an extremely cursory knowledge of the cosmic quantum eraser delayed-choice proposition.

Last edited: Nov 2, 2009
8. Nov 2, 2009

### zonde

The wave is deterministic but after transition to particle this particle thing is probabilistic.
Reason for that change is measurement event. So to me it seems the context of measurement event is cause of that randomness.

Well, there are a lot of people with different viewpoints. Basically it's not hard to find viewpoint that fits your own preferences.
The question is rather whether this viewpoint can be proved/disproved experimentally.

9. Nov 2, 2009

### DrChinese

You need to bring both streams of data together to see the effects of entanglement. If you look at either stream of data alone, you see nothing but random bits of information.