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:4, Interesting)
It does. Tunneling is instantaneous. It may even be able to transfer information, but the jury is still out on that and classical quantum mechanics says it cannot. If it can, then it can transfer information without time delay, but only over short distances and with a large energy investments that almost completely goes into losses. That way, it would basically never happen in nature and it cannot go over significant distances.
Re:Faster than Light? (Score:0, Interesting)
It isn't going faster than light, it's just shortening the distance between two points via subatomic tricks.
This is not a completely accurate explanation, but it should suffice to explain the differences between normal conductors and nano-conductors.
Normally electricity flows through the conductor by traveling through each atom, bumping electrons along the way, traversing lower then higher energy states (electron orbits).
When we get to these nanoscale pathways, there's no room for electrons to flow normally, so they just skip along the outer shell, almost like the way those motion machine balls do - one hits on one end, momentum carried to the other side, then the last ball speeds away with the momentum transferred through the in-between balls.
Same with these pathways, electron comes in, bumps an electron off on the other side, instantly, looking like it's travelled faster than light, when in reality, it just didn't travel through the material, just along the outer edges.
It sounds like parlor tricks, but it works.
Re:Faster than Light? (Score:5, Interesting)
Found this on wikipedia:
http://en.wikipedia.org/wiki/Faster-than-light#Faster_light_.28Casimir_vacuum_and_quantum_tunnelling.29 [wikipedia.org]
Faster light (Casimir vacuum and quantum tunnelling)
Raymond Y. Chiao was first to measure the quantum tunnelling time, which was found to be between 1.5 to 1.7 times the speed of light.
Einstein's equations of special relativity postulate that the speed of light in a vacuum is invariant in inertial frames. That is, it will be the same from any frame of reference moving at a constant speed. The equations do not specify any particular value for the speed of the light, which is an experimentally determined quantity for a fixed unit of length. Since 1983, the SI unit of length (the meter) has been defined using the speed of light.
The experimental determination has been made in vacuum. However, the vacuum we know is not the only possible vacuum which can exist. The vacuum has energy associated with it, unsurprisingly called the vacuum energy. This vacuum energy can perhaps be changed in certain cases.[38] When vacuum energy is lowered, light itself has been predicted to go faster than the standard value c.
Josephen called (Score:4, Interesting)
He wants his junction back
Re:Faster than Light? (Score:5, Interesting)
The reason why this is not a problem is because the electron does not actually travel from one point to the other, which would mean there were intermediary points of existence along the way. This is a quantum movement. The electron stops probably being at one place and becomes more probably in another place. It never was in any “place” to start with since placeness is not a quality of an lepton in motion.. Nevertheless, the event of the movement from one probability to the next is not really time measurable as an event, only as a measured effect.
Story time (Score:5, Interesting)
When I was young kid, in the early 1960's, I visited a ham radio operator a bunch of times. Cool radios, etc. He taught me some key things about tubes, started a long slide into technology that still hasn't stopped. I asked him about transistors. He looked at me somewhat askance and said "yeah, "I heard about them things. Tubes, son. I know tubes." And went back to teaching me about tubes, and resonance, and etc. Outside of his place, I hooked into an NRI electronics course, and spent a summer sucking that down, while running to my older friend Tony to help me with the math. NRI was teaching tubes then too, but they had an excellent section on transistors, and so I grew comfortable with them just as they were becoming interesting and more widely used. Tubes, except for certain specific jobs, just aren't used much now as we all know, and I've always been grateful for my luck in terms of timing; a few years earlier, and I'd have been looking askance at transistors myself. But instead, I've been comfortable with semiconductors right up until they got too small for me to handle (surface mount, trembling hands, etc.) And I know tubes.
The idea that another revolution of similar importance may happen in my lifetime...
Damn. I just feel like one amazingly lucky fellow. :) Now, will I be able to grasp the tech if it makes it to market? That, as they say, remains to be seen. Getting older doesn't mean you're without a clue. It just means you no longer always know where you put them.
Re:Faster than Light? (Score:4, Interesting)
I know a few famous physicists that would disagree with you on your argument that space is "nothing" and isn't "something." "Empty space" isn't actually empty at all, and space-time itself has lots of intrinsic properties. I believe there's a NOVA special on the subject available online for free if you'd like to investigate.
For instance, if you were to start spinning in empty space and no other matter or light in the universe existed (yet you were still somehow alive), you would still feel your arms being pulled outward due to your spinning motion -- even though you had no point of reference to even know that you were spinning at all. You'd still be spinning in relation to the invisible framework of space-time.
On an unrelated note, there is a controversial quantum theory that light speed in empty space is not a finite speed, but an average speed. Further, an expansion on that same theory is that photons travel at infinite speed, but in the medium of empty space, they randomly hit virtual particles which absorb and re-emit them which is what slows them down to what we measure as light speed. The rate of hitting virtual particles can be predicted statistically and works out to be in line with what one would expect in order to get the current measurement for light speed, but it could all be wishful thinking and tinkering with math.
Re:Story time (Score:3, Interesting)
I think the most interesting part of this is that yes, we are not yet out of revolutions. Interesting times, while an ancient Chinese curse, is certainly more fun than living without these new innovations. Bring them on!
And I agree, getting older these days means you may have greater insight. The worst waste of time I see in programming is the "re-invention" cycle that occurs every 5-7 years with the latest new language or methodology. And after the newness wears off, the same old approaches are gravitated towards, because they work.
Re:Story time (Score:4, Interesting)
Yes, tubes and fets share various characteristics, but there are a lot of things they don't share and I guarantee you that a good grounding (hah!) in fets of all kinds isn't sufficient to go off and do tube design beyond the very simplest applications. There have been some seriously weird tubes with no corresponding single-semiconductor solution; quite aside from the huge range of voltages involved, there are screen grids, directly heated cathodes, gas-filled regulators, CRTs (imagine depending on knowledge of a FET to make a CRT work, eh?), coupling issues, various kinds of noise peculiar to tubes, weird stuff like microphonics, just a whole host of interesting issues and devices. Plus, things you'd take as similar act quite differently, even starting just from a rectifier diode. And tubes glow in the dark. You're thinking orange, right? But an OA2 in normal operation is a beautiful, bright purple. And there are tubes that are green bar graphs, tubes that can display characters... :)
Yes, that ham made a huge difference for me, and I try to do the same - happy to wear the "Elmer" hat. Been an extra class for decades now. Also, lately, been working on a free software defined radio [fyngyrz.com] app, so in way, I'm getting right back to my roots.