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Single Molecule Memory
techtrend linked us up to a paper from Mark Reed and James Tour on
single molecule memory which, if it comes about will pretty much make space irrelevant. They say the technology is 3-5 years off.
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Actually, it's "peta" which is then followed by "exa" and then "zetta" and finally "yotta". There is a short breakdown of the meanin of the names at "http://www.ccsf.caltech.edu/~roy /dataquan/ety.html" which tells where the names come from. There is a much larger listing of magnitudes at "http://www.mcs.csuhaywa rd.edu/~malek/Mathlinks/Billion.html".
World Beach List, my latest project.
But nothing in the article says that anything in this particular paper will be implimented any time soon.
this would be cool, except:
;-)
we still dont have a decent way to transfer information through 1 molecule sized pathways...
(keep in mind, they have flipped the gate, and watched with a microscope... they did not do anything useful with it)
the gate/transistor can be that small, but if the path to get there is not, who cares
(electricity can't work well at that size, if the pathways are that small and at all decently near each other you will get massive electron tunneling, where they hop over to the next pathway ) (this is bad
optical pathways ahve not been gotten to work yet AFAIK, and even they would have problems at that level
on a more holistic level, fusion was supposed to be done 20 years ago, those incredibly large harddrives that are the size of my pinky were supposed to be done by now....
this is cool and all, but it is research that will not bear fruit for a LOOONG time
-RS
We are all in the gutter, but some of us are looking at the stars --Oscar Wilde
Grrr. my nick is "Forward the Light Brigade"...
You can see what the Tour research group is up to at Rice by going to his homepage at http://www.jmtour.com/. There is information about this project at http://www.jmtour.com/info.htm. Scroll down the page a bit.
Finally, don't forget that you can see more about the Rice nanotechnology program at The Rice Quantum Institute and The Center for Nanoscale Science and Technology. Don't forget that Rice is where the Buckyball craze started, with Smalley and Curl winning the Nobel for the discovery of its shape.
It is not just a single bit that can be in a superposition of states, but all the bits of the computation. (A superposition of states can be described as probability distribution over all the possible states the system could be in). Thus, the limit on the number of parallel computations in a binary quantum computer is 2^N, where N is the number of quantum bits (qubits) used in the computation.
The degree of parallelism this implies is staggering. Some problems that are believed to require exponential time to solve on a classical computer could be solved in polynomial time on a quantum computer. This includes factoring (think RSA encryption).
Some people overgeneralize and think that a quantum computer could solve NP-complete problems in polynomial time. Unfortunately, that's not the case (or at least, hasn't been proven). To get an answer out of a quantum computer, you need to be able to get all of the exponentially many wrong solutions to somehow "cancel out," leaving the correct solution. Doing that in the general case is non-trivial and probably impossible. Quantum compilers are a long way off.
But so far, quantum computers have proven difficult to build. The problem is getting a useful computation without a "collapse" of the wave function. (A collapse is when the system rolls the dice or whatever it does, and settles on a single state to be in. Oops, there goes your parallelism!) The biggest quantum computer I've heard about has 2 qubits. An impressive achievement, but not quite ready to port Linux to.
You've assumed that molecules are the lowest level at which we can compute;
We can go smaller, into atoms and energy and spin states of electrons in a shell, for example, both of which are different things entirely. So we haven't quite hit the limits of information and computing yet.
So lets say we use a stable lithium ion as a storage 'bit' where we can flip the electron's spin to indicate 1 or 0. We ignore the two inner s orbital electrons and concentrate on the single valence electron. You'd prolly flip it with a single photon of light. How? Beats me. Anyway, you can actually calculate the energy of the photon required to do so, and the time it takes to flip as well( ~instantaneous?) and that is some sort of limit, but there are still levels beyond that with which we could play information games, I'm sure.
You could go into multi-bit storage by including energy level as well as spin; bump up an electron 1, 2, 3 or 4 levels, and flip it's spin in either direction and we get a 3 bit storage out of a single atom. If you play with two electrons in such a system, you could conceivably get a 5 bit system, or something like that. With a complex enough atom, you could prolly get 6 or 7 bits of data off a single atom!
-AS
-AS
*Pikachu*
I read the article and came up with more questions than answers... How does it work? What are the 'off' and 'on' states? How do you read/write it? How fast can you cycle it?
I followed the link from the article to 'Mark A. Reed', one of the scientists mentioned. A quote from his personal site (deep breath): "My areas of research are quantum electron device physics; tunneling and transport phenomena in semiconductor heterojunction and nanostructured systems; reduced dimensionality effects in nanostructures; resonant tunneling transistors, circuits, and novel heterojunction devices; investigations into the physics and technology of quantum-confined electronic devices; investigation of resonant tunneling physics in a variety of heterojunction systems and materials, including 0D quantum dots and resonant tunneling transistors; and molecular electronics, nanotechnology."
...wheeze...
OK, now I know as much as I did before, and am buzz-worded to death besides. So I drilled deeper into the site and found some pictures of his current work that do give some clues. Most interesting is the illustration titled "Molecules in nanopores."
And, of course, there is his List of Publications which I probably wouldn't understand anyway. Even if they were online... Perhaps someone more competent can read these, and peruse the 'Break Junction Lab' description for us.
My take at this point is: the guy probably knows what he is talking about, but I still don't have enough information to determine if the end result would work well enough to actually be useful in '3 to 5 years'. The thing is, there are plenty of technologies that work. But only a few of them have survived the true test of fitness in the marketplace.
Jack
- -
Are you an SF Fan? Are you a Tru-Fan?
Is that a SingMolec Module in your pocket containing all Human Knowledge or are you happy to see me?
I know it may not happen for a long time, but imagine this:
You walk into your local PC parts store.
"I want 96 petabytes of memory, please."
"That's it? That will be $6.28."
It seems that as we start thinking of molecules as bits, we're getting down near the theoretical limits of information and computing. So that brings me to a few questions that I hope some knowledgable person (someone with a background in physics and computation) might be able to answer:
1) How fast can a computation happen (in a physical system) in thoeory.
2) How fast could molecular gates and molecular bits effect a computation?
3) How do you estimate these numbers would translate into Teraflops?
Quite simply, you use the spin of a single electron to determine whether you have a 0 ('down' spin) or 1 ('up' spin) for that given atom. These are read with lasers, and I believe this can be done rather quickly.
If this is the same thing, then the theory has existed for maybe three years, but they seem to have found a practical application for it. Before that, all they could do was use some sort of awkward prototype filled with lens for interferometry.
If this is indeed the same thing, it also leads to a spiffy thing: fuzzy logic. Since quantum mechanics is essentially a matter of statistics, it means an electron may be in a probabilistic state between 0 and 1. For instance, it could be:
How this can lead to more efficient calculations, I have no clue. Still, it's cool to think of a single bit as "maybe 0 but most probably 1".
Again, not sure if this is the same technology. It may just not be; but regardless, the idea remains a really cool one.
"Knowledge = Power = Energy = Mass"