A few questions about the quantum behavior of particles

[MirceaKitsune]

I've recently been interested in understanding physics and how the universe works. About a month ago, I've gotten to a conclusion which I believe might explain the basis of quantum mechanics. Fot those interested to read about it, see this thread (warning, huge post, but IMO worth looking at if you have the time and energy). Although it's a hypothesis I strongly believe in (because it makes sense in every logical aspect), it's highly incomplete and has no mathematics behind it, as others have pointed out. For this reason, I'm trying to understand a few details about quantum physics, which might help make more sense of how this works. They're the sort of thing I tend to have trouble finding in Google searches, so I thought it would be best to ask. These are the questions I have so far, though I might add new ones later if any come to mind:

 

1 - From what I heard, it's confirmed that the low mass of a particle is a key factor in its quantum behavior. But how exactly does a higher or lower mass change the behavior of such particles, if this was ever possible to measure? For example, do lighter particles have multiple states they switch between, or leap from one state to another more quickly, or have higher chances of tunneling through an obstacle? While heavier particles would do this more rarely or in a different pattern?

 

2 - Does the speed at which a particle travels affect its quantum behavior? Such as electrons in an atom that has a high velocity changing orbit more frequently than the electrons in an atom which moves slowly or stands still.

 

3 - How does the charge of a particle affect quantum behavior? Do only electrons behave by the commonly known quantum laws, or so do protons and / or neutrons? Does the behavior differ in any way for each? I assume no one knows how this goes for anti-matter too since it can't be actually tested.

 

4 - Has anyone tested how quantum particles behave in different gravity environments? Such as comparing the behavior of a particle here at ground level, with the behavior of an identical particle on the International Space Station in microgravity. Can gravity caused by nearby objects change the outcome in any way?

 

5 - Are there any known cases when not single particles, but also linked particles behave by quantum laws? In other words, are there any atoms or even simple molecules that change states or tunnel as a whole?

 

6 - My last question for now is about the double slit experiment; Each particle of light seemingly acts as if it went through both holes at the same time, until it is observed. Once observed by a person, it becomes clear which of the holes it went through. My question is this: Once the particle has been observed, does the "verdict" stick and stay the same no matter what? Or if the scientist was to close their eyes after observing the particle, then open them a few moments later, he might find that the particle went through the other hole instead? Also, if another scientist observes the particle after the first one finished observing it, might he see a different result?

[ajb]

1 - From what I heard, it's confirmed that the low mass of a particle is a key factor in its quantum behavior. But how exactly does a higher or lower mass change the behavior of such particles, if this was ever possible to measure? For example, do lighter particles have multiple states they switch between, or leap from one state to another more quickly, or have higher chances of tunneling through an obstacle? While heavier particles would do this more rarely or in a different pattern?

You can examine the transmission coefficient for quantum tunneling. Under some assumptions you see that the coefficient goes like

 

[math]T \approx e^{- \sqrt{\frac{2 m}{\hbar^{2}}}}[/math]

 

So the larger the mass the more this coefficient becomes suppressed.

 

 

2 - Does the speed at which a particle travels affect its quantum behavior? Such as electrons in an atom that has a high velocity changing orbit more frequently than the electrons in an atom which moves slowly or stands still.

We have to be careful what you mean here by velocity of a quantum particle, one needs to take care with classical notions like that. In particular we have the uncertainty relation between momentum and position. Loosely, if I know where a particle is, I don't know its speed and if I know its speed I don't know where it is!

 

This is all written into quantum mechanics. The only thing I would warn about here is that in standard non-relativistic mechanics one does not take into account special relativity. Thus, if classically we expect the particle to be moving a significant fraction of the speed of light we should take these effects into account. The Lamb shift is an example of this.

 

 

3 - How does the charge of a particle affect quantum behavior? Do only electrons behave by the commonly known quantum laws, or so do protons and / or neutrons? Does the behavior differ in any way for each? I assume no one knows how this goes for anti-matter too since it can't be actually tested.

Neutral particle also obey quantum mechanics. Also we have tested antimatter and it all seems to obey the rules of quantum mechanics.

 

 

4 - Has anyone tested how quantum particles behave in different gravity environments? Such as comparing the behavior of a particle here at ground level, with the behavior of an identical particle on the International Space Station in microgravity. Can gravity caused by nearby objects change the outcome in any way?

This is very interesting. There have been few tests of gravity at the sub millimeter level. So there is still some scope here for new results.

 

That said, effects of gravitational time dilation on atomic clocks has been seen. Look up the HafeleKeating experiment.

 

Others here can probably say a lot more about atomic clocks in gravitational fields.

 

 

5 - Are there any known cases when not single particles, but also linked particles behave by quantum laws? In other words, are there any atoms or even simple molecules that change states or tunnel as a whole?

We have lots of quantum collective behavior observed in condense matter physics. BoseEinstein condensates, superfluidity, superconductors, composite fermions, bands in conductors, semiconductors and insulators, electron-hole droplets and many many more...

 

I hope what I have said is of some help.

[MirceaKitsune]

Thank you, that is helpful. More answers are of course welcome to paint a better picture from all.