- #1
MonstersFromTheId
- 142
- 1
I've seen more explanations than I can count of how Q.T. happens, but all of them involve basically variations of the same specific example of an electron encountering a magnetic field as a barrier.
This leaves me with several questions not answered by this specific example:
1) Are electrons the only kinds of particles known to exhibit this behavior?
Or are there other kinds of particles that could exhibit this behavior as well? For that matter does the type of particle even have anything at all to do with whether or not it could exhibit the behavior of quantum tunneling? Are certain types of particles more or less likely to exhibit this behavior?
2) When a particle tunnels through a barrier, does it (for lack or a better term) "move" from one side of the barrier to the other instantaneously? Or is there some finite time it takes for this transition to occur?
3) Can quantum tunneling, strictly speaking, even be considered "movement" in the every day sense of the term?
The impression I get (and this could be a severely mistaken impression) is that when a particle "tunnels" through a barrier, it isn't like pushing a marble through a wall of clay.
That is to say that the particle, from instant to instant, isn't actually "moving" through the barrier where at a given moment it's a quarter of the way through the barrier, a moment later it's half way through the barrier, a moment later it's three quarters of the way through, and finally it's through the barrier.
Instead, (Geeze this is hard to come up with words to describe), if you were to think of the particle's initial position on one side of the barrier as "Point- A", and its later position on the other side of the barrier as "Point- B", there is no "Point - C" lying between Point - A and Point - B at which you could expect to find the particle. The "movement" is discontinuous and discrete? The particle essentially "jumps" from Point - A to Point - B without ever having actually "traveled" through the intervening space between Point - A & B? Am I getting that essentially correct?
4) The "barrier" used as an example in all the explanations I've seen to date is a magnetic field. What other types of "barriers" could be envisioned?
My impression is that almost any condition representing a level of potential energy in excess of the amount of energy the particle has to cross that barrier would do.
Which leads me to an interesting thought - could a change in position or "effective speed" be considered a "barrier"?
Consider a particle moving at a steady speed of V with no forces acting on it so that S=VT applies.
For a particle moving at a constant speed of Vc, that starts out at an initial position Si, there is a maximum distance S=Sf-Si that it could move for any chosen value of T=Tf-Ti, essentially because it doesn't have the energy required to cover any greater (or lesser) distance in the allowed period of time.
Could that value of "S" also be considered a "barrier" that the particle could also "tunnel" across? That is to say could the phenomenon of quantum tunneling cause a particle to move farther (or even not as far) as it should while moving at a "constant" velocity under conditions where S=VT would normally apply?
"But they forgot one thing. Monsters John. Monsters from the Id!"
Lt. 'Doc' Ostrow in Forbidden Planet; MGM 1956
This leaves me with several questions not answered by this specific example:
1) Are electrons the only kinds of particles known to exhibit this behavior?
Or are there other kinds of particles that could exhibit this behavior as well? For that matter does the type of particle even have anything at all to do with whether or not it could exhibit the behavior of quantum tunneling? Are certain types of particles more or less likely to exhibit this behavior?
2) When a particle tunnels through a barrier, does it (for lack or a better term) "move" from one side of the barrier to the other instantaneously? Or is there some finite time it takes for this transition to occur?
3) Can quantum tunneling, strictly speaking, even be considered "movement" in the every day sense of the term?
The impression I get (and this could be a severely mistaken impression) is that when a particle "tunnels" through a barrier, it isn't like pushing a marble through a wall of clay.
That is to say that the particle, from instant to instant, isn't actually "moving" through the barrier where at a given moment it's a quarter of the way through the barrier, a moment later it's half way through the barrier, a moment later it's three quarters of the way through, and finally it's through the barrier.
Instead, (Geeze this is hard to come up with words to describe), if you were to think of the particle's initial position on one side of the barrier as "Point- A", and its later position on the other side of the barrier as "Point- B", there is no "Point - C" lying between Point - A and Point - B at which you could expect to find the particle. The "movement" is discontinuous and discrete? The particle essentially "jumps" from Point - A to Point - B without ever having actually "traveled" through the intervening space between Point - A & B? Am I getting that essentially correct?
4) The "barrier" used as an example in all the explanations I've seen to date is a magnetic field. What other types of "barriers" could be envisioned?
My impression is that almost any condition representing a level of potential energy in excess of the amount of energy the particle has to cross that barrier would do.
Which leads me to an interesting thought - could a change in position or "effective speed" be considered a "barrier"?
Consider a particle moving at a steady speed of V with no forces acting on it so that S=VT applies.
For a particle moving at a constant speed of Vc, that starts out at an initial position Si, there is a maximum distance S=Sf-Si that it could move for any chosen value of T=Tf-Ti, essentially because it doesn't have the energy required to cover any greater (or lesser) distance in the allowed period of time.
Could that value of "S" also be considered a "barrier" that the particle could also "tunnel" across? That is to say could the phenomenon of quantum tunneling cause a particle to move farther (or even not as far) as it should while moving at a "constant" velocity under conditions where S=VT would normally apply?
"But they forgot one thing. Monsters John. Monsters from the Id!"
Lt. 'Doc' Ostrow in Forbidden Planet; MGM 1956