Quantum-Tunneling Electrons Could Make Semiconductors Obsolete 276
Nerval's Lobster writes "The powerful, reliable combination of transistors and semiconductors in computer processors could give way to systems built on the way electrons misbehave, all of it contained in circuits that warp even the most basic rules of physics. Rather than relying on a predictable flow of electrons that appear to know whether they are particles or waves, the new approach depends on quantum tunneling, in which electrons given the right incentive can travel faster than light, appear to arrive at a new location before having left the old one, and pass straight through barriers that should be able to hold them back. Quantum tunneling is one of a series of quantum-mechanics-related techniques being developed as possible replacements for transistors embedded in semiconducting materials such as silicon. Unlike traditional transistors, circuits built by creating pathways for electrons to travel across a bed of nanotubes are not limited by any size restriction relevant to current manufacturing methods, require far less power than even the tiniest transistors, and do not give off heat or leak electricity as waste products, according to Yoke Khin Yap of Michigan Technological University, lead author of a paper describing the technique, which was published in the journal Advanced Materials last week."
Re:Faster than Light? (Score:2, Informative)
Re:Sorry to those in the religion of Einsteinianis (Score:5, Informative)
Phase velocity exceeds c, not group velocity. If you guys wanna prove Einstein wrong, you're gonna have to work a little harder.
Re:Why? (Score:3, Informative)
Look, it's not a religion, you were taught a set of beliefs and you refuse to question them. Why?
period.
I'd like to think that some day we'll figure out how to make things go faster than light. But we haven't done that yet, and it would be big news if we had. Describing it that way in the summary is simply wrong.
FTL, yes but no info (Score:5, Informative)
Can't the slashdot editors be more active with their copy? Nothing goes faster than light. period.
Correction: no information travels faster than light. It is easy to imagine a system which looks like something is moving faster than light: shine a bright enough torch on the moon. If you move the torch fast enough it will look like the spot on the Moon is moving faster than light. This is perfectly fine because there is no way to change the where the beam moves if you happen to be where the beam is pointing at a particular time i.e. no information flows between one spot and the next because everything is under the control of the torch wielder back on earth.
In QM tunnelling the transmission speed of information is always below the speed fo light and so there is no problem (if you know secondary [high] school physics this is like the difference between phase velocity and group velocity of a wave in a wave guide). However where the editors messed up is the statement:
...in circuits that warp even the most basic rules of physics.
These circuit DO NOT warp the basic rules of physics. Quantum mechanics IS a "basic rule of physics" - it is certainly counterintuitive but it is a fundamental rule of physics.
Re:Faster than Light? (Score:5, Informative)
Usually Nerval's Lobster promotes self-described tech-writer-gun-for-hire/Slashdot "editor" Nick Kolakowski's work [slashdot.org]. In this case, the author of the Slashdot content is Kevin Fogarty [slashdot.org], who recently brought us such gems as thinly-disguised press releases for Cumulus Networks [slashdot.org], Enterasys [slashdot.org], and Heavy Reading [slashdot.org], all of which use curiously-similar ambiguous stock photos from Shutterstock... My guess: the people behind the article (which we can't read) paid for it to be summarized and posted on Slashdot so they could pursue further funding by claiming their work has been "featured" (legitimized) on Slashdot.
This has been going on for some time now with Nerval's Lobster. Many people have learned not to feed the troll (don't post comments on Nerval's Lobster submissions), but if you're just joining us, welcome! And try not to feed the troll.
Re:Faster than Light? (Score:5, Informative)
But what if you have a mile long pole and correlate it's movements into a form of communication. As soon as you move the pole on one end it would instantaneously move on the other for instantaneous communication.
Nope. The motion propagates to the far end at the speed of sound in the pole - much faster than sound in air, but glacial compared to light in vacuum.
Don't bother looking for an unobtanium with near-infinite stiffness and an internal speed of sound faster than light-in-vacuum. The motion at one end encodes information about what is happening at that end and that information is propagated down the pole by interactions between the pole's component particles, interactions that all are no faster than the speed of light.
Re:FTL, yes but no info (Score:2, Informative)
If information was transferred from A to B faster than light, between the event at A and at B is a space like interval, and thus there is a reference frame such that the event at B occurred before the one at A, which violates causality (Since the event at A caused the event at B).
https://en.wikipedia.org/wiki/Spacetime#Space-like_interval
I hope that clears up the issue for you!
Re:Faster than light ?! (Score:5, Informative)
Wrong. Dirac did. And it led him to the prediction of antimatter. And all quantum field theories are relativistic quantum mechanics.
What hasn't yet been managed is to unite general relativity and quantum mechanics. However that's irrelevant for the FTL tunneling question because the speed of light limit is a property of special relativity, which has completely and fruitfully been united with quantum mechanics a long time ago.
Relativity tells us that if we could travel faster than light, then we could also violate causality. So unless you are willing to give up causality, relativity indeed does ban travelling faster than light.
Re:Faster than Light? (Score:5, Informative)
Faster than light expansion is just a mathematical oddity caused by the use of a particular coordinate system. Not that there's anything wrong with it, just that nobody ever seems to explain it properly.
Local distances and times are easy to measure objectively using clocks and measuring rods, but the definition is not so clear and unambiguous anymore when you're talking about large distances in the expanding universe. Different metrics exist, defining distances, times and speeds in a different way, yielding wildly different values while giving the same tangible results for any actual event. I will give you two ways of looking at the universe: the first conserves the speed of light but looks very weird, while the other looks more normal but does not respect Special Relativity. Under General Relativity, which allows a wider range of metrics, both models are perfectly valid and consistent. I will disregard the effects of gravity, but otherwise it should be a pretty accurate description, certainly enough to explain what "space itself" really means.
If you define distances, times and speeds using the common sense definitions from Special Relativity (using beams of light to measure distances, always assuming a constant speed of light), distant galaxies are traveling away from us at high speeds (but less than the speed of light) and therefore time passes more slowly for them. Since this has been the case ever since the big bang, they are younger than us at this point in time. They don't just look younger because we had to wait for their light to get here, but they really are younger "right now" even if we take the traveling time of light into account. If we could "look" at them directly without having to wait for the light to get here, like we could do in a mathematical model, we would "see" the universe getting younger and younger, and clocks ticking ever more slowly, the further out we "look" in our expanding universe. At a distance of c times the age of the universe, the big bang is happening "right now". This gives the universe a finite size (assuming nothing existed before the big bang) but it does contain an infinite amount of matter thanks to Lorentz contraction. Everything near the boundary is squished in the direction of the expansion so that an infinite amount of stuff fits in this finite amount of space.
This metric is a bit cumbersome because it gives us a special position at the center of the universe while in fact there's nothing special about our position at all. Some other, distant civilisation (in the distant future according to the above metric) will actually say that we don't exist yet and our galaxy is much younger than theirs, "now". (Using their definition of "now"). That's just the classic twin paradox, nothing really wrong with that, but it does make our point of view a bit subjective.
So cosmologists came up with a better metric, the cosmological model: they define time as whatever is measured by local clocks that are traveling at the same speed as the average galaxy in that area (the expansion speed vector), undoing time dilation due to the expansion and thereby making the whole universe the same age. Local distances are defined in such a way that objects look pretty much the same size everywhere (no Lorentz contraction due to expansion speed), which can be achieved by defining distances in function of a constant speed of light relative to the expanding universe. So in effect we stretched the universe and sped it up, just by using a different definition of "now" and by measuring distances differently. With this model, the universe looks nicely homogenous and truly infinite, making many calculations a lot easier. There's no longer anything special about our location.
But because we changed our definitions of space and time, some of the old assumptions from special relativity are no longer valid. Things can and do fly away from us at speeds well in excess of the speed of light simply because we are defining their speed differently. But the light from those places will ne