Physicists Propose New Kind of Quantum Tunneling

KentuckyFC writes to tell us that scientists from the UK and Germany are proposing a third kind of quantum tunneling. They propose that a quantum particle is capable of changing into a pair of "virtual particles" capable of passing through a potential barrier before changing back. The supposition also provides some interesting methods of possibly testing string theory. So many interesting and useful possibilities, I guess that just means it will be debunked faster than other scientific theories.

Comments

Re:let's hear it for optimism

[who knows my name]

Does anyone else get an uneasy feeling about the use of the word debunk in the summary?

Is real but rare

[physburn]

This won't be debunked, its true. Once you look at the feynman diagrams its obviously a possible effect. Trouble is, it will have a very low probability, at each end of the conversion possible you've got two weak force vertices, and one of the heavy 80/90 GeV/c^2 W or Z weak force carriers. So the total amplitude goes as E^2/M_w^2 g_w^4 and square that for a probablity. So for photons that might need to tunnel (optical frequencies about 1eV) you have a tunnelling probability of 10^-18, that so very rare physicists will probably never see it.

.

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Re:Is real but rare

[physburn]

Standard tunnelling goes roughly as

exp(-delta E L/hbar c)

where L is the length it needs to tunnel and E is energy barrier the particles tunnelling though.

The second type of light through walls, depends on there being a axion or some other very light weakly interacting particle for the photons to change into, and so the probability could be anything, depending on the properties of the new particle.

Neither the second or third kinds, depend (much) on the length the particle has to tunnel through.

Re:Please explain to me the following...

[damburger]

Um, I am not sure where to start.

You are spouting physics buzzwords with no apparent grasp of what they are or what they mean. Don't try and learn about science from the media - this is the kind of confusion that results.

Dark matter is just matter we can't see. It almost certainly has nothing in particular to do with the Higgs Boson, which is a proposed mechanism by which all matter (dark or otherwise) has mass.

The barrier in question is a potential barrier, and seeing as we live in a three dimensional universe it is a three dimensional barrier; sometimes a potential barrier will be represented in 1 or 2 dimensions for clarity.

Re:QM explains Transistors?

[Frenchman113]

The Bohr model of the atom, while incorrect, is a quantum model because it predicts that the electrons of a hydrogen atom can only hold specific quantum energy levels.

Wrong Diagram!

[Roger W Moore]

This won't be debunked, its true. Once you look at the feynman diagrams its obviously a possible effect.

If you read the paper and not the very bad summary in the article - along with a wrong diagram - then this is not what they are suggesting. They calculate the neutrino digram shown in the article and which you estimated and come up with a probability of O(10^-130) times a function of the neutrino mass, barrier thickness and photon energy. This would be an interesting way to measure neutrino mass if the probability were not so low.

What they are actually wanting to test is whether there are new, fractionally charged particles out there. So this is not something that is guaranteed to work. In fact I do not see how we would not have already seen such particles before now in virtual effects in K and B experiments if nothing else...but I have not looked at it in detail.