What does Wikkepedia mean when they talk about Quantum tunnelling

[Neopets]

This is what it says on Wikipedia :

Quantum tunneling refers to the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically could not surmount because its total mechanical energy is lower than the potential energy of the barrier.

But I would like to know, what can a particle travel through, and what kind of particles are traveling through the barriers? Just like electrons, or do they mean quarks?
So does this mean that despite the total energy, that the particle can somehow be forced to travel through the barrier?

 

[Dr Lots-o'watts]

The easiest concrete example is when you get an electric shock.

The particle is an electron, the barrier is the layer of air between your finger and the grounded metal doorknob. Normally electrons wouldn't be able to travel through the air, but somehow, the extra electrons on your finger know there is a metal doorknob really close and they run the air gap to reach it. This is what quantum tunneling is about. The final energy is lower than the initial energy. But in between, "magic" (tunneling) happened.

 

[granpa]

http://www.mpq.mpg.de/cms/mpq/en/news/press/archiv/2007/07_04_05.html

[PLAIN]http://www.jyi.org/articleimages/1006/originals/img0.jpg
There are two paths of getting to the other side of a mountain. In classical physics, one must climb the mountain to get to the other side. In quantum physics, objects can cross the mountain by tunnelling horizontally through it. Image courtesy of the Max Planck Institute for Quantum Optics.

 

[ZapperZ]

This is what it says on Wikipedia :

Quantum tunneling refers to the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically could not surmount because its total mechanical energy is lower than the potential energy of the barrier.

But I would like to know, what can a particle travel through, and what kind of particles are traveling through the barriers? Just like electrons, or do they mean quarks?
So does this mean that despite the total energy, that the particle can somehow be forced to travel through the barrier?

Any quantum particle can tunnel through barriers. However, it doesn't mean that the probability of tunneling is equal for all particles. There are mitigating factors. The most common will be electron tunneling. It is so common, it is some often used in electronics. Many of the field emitters in flat-panel displays are electron emitted via "field emission", i.e. tunneling.

The barrier can be anything. In the case of electron tunneling, it is often an insulation layer. This is where there is a large potential barrier. Classical scenario prohibits electrons from going through this barrier.

Zz.

 

[robert80]

This is what it says on Wikipedia :

Quantum tunneling refers to the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically could not surmount because its total mechanical energy is lower than the potential energy of the barrier.

But I would like to know, what can a particle travel through, and what kind of particles are traveling through the barriers? Just like electrons, or do they mean quarks?
So does this mean that despite the total energy, that the particle can somehow be forced to travel through the barrier?

I think it depends on, which kind of barrier you have... When you have an electron the potential barrier is ment. When you have mass, there is a gravitational barrier ( as the black holes emit some small amount of light). But I do not know if that's 100% true.

 

[Neopets]

http://www.mpq.mpg.de/cms/mpq/en/news/press/archiv/2007/07_04_05.html

[PLAIN]http://www.jyi.org/articleimages/1006/originals/img0.jpg
There are two paths of getting to the other side of a mountain. In classical physics, one must climb the mountain to get to the other side. In quantum physics, objects can cross the mountain by tunnelling horizontally through it. Image courtesy of the Max Planck Institute for Quantum Optics.

This is really nice and helpful thank you all so much :)

 

[Neopets]

I think it depends on, which kind of barrier you have... When you have an electron the potential barrier is ment. When you have mass, there is a gravitational barrier ( as the black holes emit some small amount of light). But I do not know if that's 100% true.

Interesting thanks :)

 

[Neopets]

Any quantum particle can tunnel through barriers. However, it doesn't mean that the probability of tunneling is equal for all particles. There are mitigating factors. The most common will be electron tunneling. It is so common, it is some often used in electronics. Many of the field emitters in flat-panel displays are electron emitted via "field emission", i.e. tunneling.

The barrier can be anything. In the case of electron tunneling, it is often an insulation layer. This is where there is a large potential barrier. Classical scenario prohibits electrons from going through this barrier.

Zz.

helpful ! :) thanks

 

[Neopets]

The easiest concrete example is when you get an electric shock.

The particle is an electron, the barrier is the layer of air between your finger and the grounded metal doorknob. Normally electrons wouldn't be able to travel through the air, but somehow, the extra electrons on your finger know there is a metal doorknob really close and they run the air gap to reach it. This is what quantum tunneling is about. The final energy is lower than the initial energy. But in between, "magic" (tunneling) happened.

Ok, yeah that helps to know, thanks for the explanation :)