Complete Vacuum and Particle/Wave

[Mukilab]

Why may one not have a complete vacuum?

 

How does every single particle both function as a particle and a wave?

 

How does quantum tunneling work?

 

~Cyf

[Klaynos]

Three very different questions....

 

1. Quantum fluctuations, virtual particle pairs pop into and out of existence all the time... http://en.wikipedia.org/wiki/Quantum_fluctuation

 

2. How? Because that is how they act, if you try and measure wave properties you can, also if you try and measure wave properties you can. They really are something different that we don't have a good macroscopic analogy for so humans find it difficult to comprehend.

 

3. A hand wavey answer is that, a particle is held in a finite quantum well, this particle can borrow energy for a very short amount of time because of the uncertainty principle meaning it has enough energy to get out of the well but it only has that energy for a short amount of time... A better explanation is that if you solve the probability wave equations at the boundary for a finite potential there is a finite probability that the particle is found within the area outside of the well, in the wall, if the wall is thin enough the probability of finding the particle outside of the well is high enough that sometimes it happens.

[Mukilab]

2. How? Because that is how they act, if you try and measure wave properties you can, also if you try and measure wave properties you can. They really are something different that we don't have a good macroscopic analogy for so humans find it difficult to comprehend.

 

 

Does this make sense?

 

I also realise that they are three questions.

[ajb]

Does this make sense?

 

I think it does make sense and get to the heart of quantum theory.

 

There are various way you can formulate quantum theory, but that does not really matter. Klaynos' point is that if you force yourself to adopt an interpretation in terms as macroscopic ideas then you will have to consider this mix of particles and waves. This is where many misconceptions and philosophical debate enter.

[Bob_for_short]

Why may one not have a complete vacuum?

Yes, on may have a complete quantum vacuum as the lowest energetic state. Quantum "particles" are just excited states, i.e., states with the energy superior to the lowest one. At low temperatures the energy level populations are depleted so on can have the ground (vacuum) state prepared and observed in many systems with excitation threshold.

[ArjenDijksman]

How does every single particle both function as a particle and a wave?

How does quantum tunneling work?

A bouncing droplet on a liquid surface wave works quite well to get insight into these quantum properties:

• Single-particle interference observed for macroscopic objects
  
• Unpredictable Tunneling of a Classical Wave-Particle Association
  

 

Arjen

[Mukilab]

I think it does make sense and get to the heart of quantum theory.

 

There are various way you can formulate quantum theory, but that does not really matter. Klaynos' point is that if you force yourself to adopt an interpretation in terms as macroscopic ideas then you will have to consider this mix of particles and waves. This is where many misconceptions and philosophical debate enter.

 

Sorry, I meant that he wrote it behaves like a wave twice, I thought he may have meant that it behaves like a wave and behaves like an atom.

 

A bouncing droplet on a liquid surface wave works quite well to get insight into these quantum properties:

• Single-particle interference observed for macroscopic objects
  
• Unpredictable Tunneling of a Classical Wave-Particle Association
  

 

Arjen

 

Thanks

[swansont]

I think it does make sense and get to the heart of quantum theory.

 

There are various way you can formulate quantum theory, but that does not really matter. Klaynos' point is that if you force yourself to adopt an interpretation in terms as macroscopic ideas then you will have to consider this mix of particles and waves. This is where many misconceptions and philosophical debate enter.

 

That's why I'm not a fan of the "borrowing energy" explanation of tunneling. It's an explanation that relies on a classical mindset.