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

let's hear it for optimism

[phantomfive]

So many interesting and useful possibilities, I guess that just means it will be debunked faster than other scientific theories.

Your glass the wrong size often there, mate?


A good percentage of us believe FTL travel is possible. You came to the wrong place with that attitude.

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?

Re:let's hear it for optimism

[TheRaven64]

Not necessarily... the more exciting an idea is, the more interest it attracts, and so the quicker its ideas are either proven true or false.

Ideas in physics are never proven true. They are shown not to contradict any existing evidence, that is all. I can't think of any more than a few decades old which have survived even this. The best most theories can hope for is being shown to be a reasonable approximation within certain constraints. Eventually it may be possible to find a theory which both makes meaningful predictions and isn't contradicted by experimental results for a much longer time, but this hasn't happened yet and is unlikely to for quite a long time.

Physics is not about finding things that are 'true' it is about finding things that make useful predictions. Newtonian motion is not 'true', but it makes predictions that are sufficiently accurate (as long as you are not travelling at more than a tiny fraction of the speed of light or near a very large gravitational force) that we can use them.

Re:let's hear it for optimism

[pleappleappleap]

So, to put it more succinctly, you advocate that we delude ourselves?

No, but I advocate that we advance science with the hope that our hypotheses might be correct, rather than with a firm belief that our hypotheses are incorrect.

Re:What?

[phantomfive]

Where's the revolution when you need one?

Yeah, why haven't you been doing your math and physics to create this revolution that you see so clearly?

The standard model isn't wrong, any more than newtonian physics is wrong. It works great until you get to the edges, then of course you need relativity, but no one knew that until a few hundred years after Newton when we started getting experiments with strange results. Einstein was the one who explained those results.

Physics models are explanations of what we observe, which is why experiments are crucial. Unless we make more observations, we will have nothing to do but extrapolate current theories, which as you mentioned, break down at extremes, since we don't have as much experimental data at those points.

You want a revolution? Make one!

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.

.

Quantum Mechanics feed at Feed Distiller, come there and make your own feeds

Re:Is real but rare

[Anonymous Coward]

"This won't be debunked, its true. Once you look at the feynman diagrams its......"

And even though everything else may be uncertain, and a thoery which predicts everything down to the smallest bit of truth is lacking, you state with confidence that anything found in feynman diagrams must be true?

Models are just models.

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:What?

[Grokmoo]

You make a mistake in lumping quantum theory in with String Theory.

There is at present no evidence whatsoever that quantum mechanics, quantum electrodynamics, and so on are wrong. These theories are the best tested theories in human history (certain predictions about energy levels such as those in the hydrogen atom have been verified to 12 or so digits of accuracy.) Quantum mechanics is at this point the best tested and thus most probably correct theory in physics by far. This does not mean that there isn't another underlying theory that will make somewhat different predictions, but the differences would have to be fantastically small.

String theory, on the other hand, has basically no evidence against it, but also virtually no supporting evidence. This is mostly because it hasn't really come up with much in the way of testable claims.

cat

[RuBLed]

Great!... Now we need to not only guess if Schrodinger's cat is alive or dead but also if it is still inside the box as well.

Re:cat

[JustOK]

He's just spinning in his grave. We're just not sure what direction he's spinning.

Re:cat

[MadKeithV]

Strange.

bah, quantums

[Anonymous Coward]

I just tunnel over SSH. It works fine...

No, no, no! They cannot do this.

[mrRay720]

They already don't quite understand the two types of quantum tunneling they already have, and they want to have a third? Everyone knows that you get your existing shit in order before you go expanding, especially in the current economic climate. Like two types isn't enough already anyway!

Who do they think they are, string theorists??

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:What?

[damburger]

I never ceased to be tickled by people loudly and ignorantly arguing against the reality of quantum mechanics USING A MACHINE DRIVEN BY FUCKING SEMICONDUCTORS. Its like the flat Earth society getting its message out through satellite television.

Quantum mechanics, like any science, is not a religious doctrine. It doesn't have to be complete and all encompassing to be right; it just has to fit the observations for everything we have tried so far. When it stops fitting the observations, we will give it up (or more likely, refine it in some subtle way) and move on.

Re:What?

[damburger]

But it is worth mentioning that any new physics at this point, be it MoND, String theory or anything else, is more like a refinement of existing theories than a complete overhaul. If we were very wrong about the laws of physics, then our technology which relies on being tightly fine tuned to them (space probes for Newtonian dynamics, GPS systems for relativity, anything with a semiconductor for quantum mechanics) simply wouldn't work. They do work, and the work with astonishing accuracy.

Re:What?

[damburger]

I suggest you take up the notion that E=MC^2 is 'wrong' with a survivor of Hiroshima or Nagasaki. If matter/energy equivlance were wrong nothing nuclear would work. Including the Sun, which is essentially a giant, gravitationally bound, thermonuclear explosion.

The notion that light bends is not 'probably' true, it IS true because it was famously measured by Eddington during a solar eclipse. There seems to be some notion amongst the general public that Einstein pulled relativity out of his butt and physicists just accepted it because it was cool. This is not the case at all.

Special relativity was accepted because it explained phenomena that could not be explained by previous theories, and because it has been constantly verified by experiment ever since (time dilation has been measured on aeroplanes using very accurate atomic clocks, and mass dilation is a daily fact of life in any particle accelerator facility you care to name).

General relativity was accepted only because someone went out there, took some measurements, and saw they confirmed Einstein's predictions. Furthermore, we now have everyday technology that depends on GR being, admittedly within certain bounds, correct.

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.