Quantum Fuzziness? Does anyone want to chat about how weird physics is?

[Armand]

Hey- can someone who is a sci-fi fan explain quantum fuzziness to me a little better... My understanding is that quantum particles can exist in more than one place at a time unless you try to see exactly where they are, then they suddenly exist only in one place (????) So, I accept that this is true (if I understood it correctly) but isn't that sort of like saying, "When no one is looking at me, I can turn invisible"?

[[deleted user]]

I struggle with this (like most people, I guess), but as I understand it (if 'understand' is the right word!), the idea is that quantum 'particles' only appear to us as particles when you have a piece of equipment that detects their physical position. If you have a piece of equipment that, instead of detecting their position, detects their movement, they don't appear to us as particles at all, but as waves, and waves aren't just in one place, they're spread out across space.

isn't that sort of like saying, "When no one is looking at me, I can turn invisible"?

Yes, pretty much! The point is that you have no idea what quantum particles or waves are doing when you're not looking at them, and some physicists, such as Bohr, said that it was meaningless even to ask.

[Armand]

Chris wrote: " quantum 'particles' only appear to us as particles when you have a piece of equipment that detects their physical position. If you have a piece of equipment that, instead of detecting their position, detects their movement, they don't appear to us as particles at all, but as waves..." thanks- this is helpful.

[Leesa]

I love reading articles about quantum mechanics and related things like branes and string theory and so on, but many times it breaks my brain after awhile. I keep trying!

[KumeKei]

I can't really explain it but a have a nifty theory about quantum particles.
Basically they may exist in a dimension we just cannot perceive fully and because of our own lack of dimensional sight they appear to behave differently in different situations when the truth may be far simpler than it seems.

[RB]

One does not simply explain Quantum Physics ;-)
However, I do recommend these titles - they are fairly easy reads that are comprehensible for laymen that are no complete strangers to the topic:

David Deutsch's The Fabric of Reality: The Science of Parallel Universes--And Its Implications

In Search of the Multiverse by John Gribbin (You may want to start with this one)

[Peggy]

If you like podcasts, check out "The Titanium Physicists:" http://titaniumphysicists.brachiolope...

Three physicists try to explain complicated concepts to a layperson. It's the closest I've ever come to grasping how time travel is possible.

[Sooz]

the 'fuzziness' of subatomic particles is best explained (at least it explained it best to me) by Heinsenberg's Uncertainty Principle that states when it comes to a subatomic particle you can either know exactly where it is -or- you can know it's path (velocity and orbit). you cannot know both ... not at the same time anyway. so if you focus your attention on the particle you can pinpoint it's location but if you stand back and look at the bigger picture you observe an orbit and that particle has the potential to be anywhere on that orbit. the orbit is a wave of possibility .. as Wizard Boy pointed out.

so yeah, you may seem to be invisible but only because you have the potential to be anywhere at that particular moment. at least this is how i understand it.

and, as Wizard Boy also pointed out, we only know how these particles act when we are observing them. some physicists say the very act of observing them impacts their behaviour.

[Kevin]

The Uncertainty Principle postulates limits on what we can know, but you can know both position and momentum within certain limits, but you can't know both exactly. But unless you're dealing with very small objects, classical mechanics is a great approximation.

When you deal with small objects like electrons, we've learned that matter and waves, which are classically different, represent different cases of the same thing. Electrons behave as both particles and waves, and so do photons. Because of this wave-like property, quantum mechanics uses probability densities to describe their properties instead of deterministic equations. This can give the impression that things can exist in more than one location until measured, but that's not the case. They exist in only one location, but we don't know if they are in a location until we measure. Make sense?

[Trike]

Here's an interesting -- and brief -- description:

http://perfect-sense.in/wp/quantum-fu...

[Sarah]

Quantum Fuzziness is when I first wake up in the morning, rub my eyes, and stare the numbers on my alarm clock as they continue to tick in a direction I don't want them to go. The level of my eye squintiness is inversely proportional to the speed at which the clock ticks. I hate that clock, but I'm afraid that if I break it, but world will stop...

[Chris]

My understanding of quantum uncertainty is that every particle is quantum entangled with a sizable number of other particles, meaning that its position and momentum are direct functions of those other particles' positions and momentums.

This basically means you can't accurately measure both a particle's position and momentum without measuring the position and momentum of any particles it is entangled with. And since you can't accurately measure that information about those particles without tracking their quantum entanglements...it snowballs from there to ridiculous proportions.

So, to put it into layman's terms, you can't precisely measure a particle's momentum and position without doing so for about ninety percent of the particles in the universe, all at the same time. Which is something that will probably never happen.

[Steven]

Most of the fuzziness about quantum theory is due to our lack of ability to properly see what is going on at that level of reality. A lot of copy is made upon guesswork and theories, but until we're capable of actually observing what's happening at the quantum level, that's all they'll be.

Kumekei wrote: "Basically they may exist in a dimension we just cannot perceive fully and because of our own lack of dimensional sight they appear to behave differently in different situations when the truth may be far simpler than it seems."

Or far more complex. Either way, it's as good a possibility as any I've heard.

Fortunately, it doesn't stop us from using the principles of quantum physics as we understand them: Our electronics are built upon quantum theory; and we can write inventive stories about them (I gave it a shot, and the results turned out pretty good... just sayin').