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As pointed out in David Deutsche's The Fabric of Reality , no encryption based on large primes is ever indefinitely secure.

While the factorization of large prime numbers is currently an intractable task, quantum computing is very likely to make it as tractable as multiplication.

For instance, Shor's Algorithm, first discovered in 1994, has already been implemented to factor the number 15 -- to 3 and 5 with 80% accuracy. (If anyone knows what it got the other 20% of the time, I'm interested!)

Now certainly 15 isn't comparable to a 1024-bit RSA key, but it's only a start for quantum computers. Using entanglement and interference, one can have very large primes factored in a matter of minutes! All we have left to do is actually build a device that does it ... and currently decoherence is the largest obstacle to overcome.

So, if you really want information to be secure, and remain secure indefinitely, a better method of encryption which does not rely on the factorization of large primes needs to be implemented.

Peter Shor even wrote a poem about it. =P

-------
If you don't take responsibility
for what goes into your mind ...
Someone Else Will!

With all sorts of EM disturbances that are recoverable in atomic-level computing like we have today

I have to wonder what type of redundancy and error correction will have to be built into quantum computing. ... I'm not necessarily asserting that it will happen

First, I'd like to point out that quantum computation and quantum encryption are two almost completely separate concepts. Quantum encryption is based on the fact that quantum states cannot be measured without altering. The most common example is the polarization of a photon, but it will work for any quantum state, so long as there exist, effectively, two unique states that can transmit the data.

Quantum computation, however, is much more complex and much more interesting. Quantum computers are based on the concept of quantum entanglement, the ability of a quantum state to exist in a superposition of all of its mutually exclusive states: It's a 1 and a 0. However, this is not as easy to use as one might think. While it's true that if you have n quantum logic gates you have the ability to input 2^n data values simultaneously (as opposed to only 1 piece of data if you have n digital logic gates), this is not going to be the end of classical computing for a few reasons. First, quantum computers have to be perfectly reversible. That means for every output there's an input and vice versa. And there has to be no way of knowing the initial states of the data. You don't process data, you process probabilities in a quantum computer; if you know exactly what any one value is throughout the computation, you can find out all of the values: the superposition ends and you're stuck with a useless chunk of machinery. This means YOU CAN ONLY GET ONE RESULT FROM ANY QUANTUM COMPUTATION, THE END RESULT. You can't see what the data in the middle is or the computer becomes useless. (Landauer's principle makes heat loss data loss. When your processor gets hot, it's losing data. If the same thing happened to a quantum computer, it wouldn't be quantum anymore.) Decoherence is what happens when you randomly lose data to the environment by design, not by choice, and the superposition ends. This is bad for Q.C. Oh, and quantum computers can only do *some* things faster, like prime factorization and discrete logarithms. Not multiplication or addition. Plus, the circuits that would do basic arithmetic would be bigger and slower than what you've currently got.

So what does this all mean? It means that quantum computers are going to provide some advantages (real quick big number factorization), and some disadvantages (that whole RSA standard). The most realistic initial use of quantum computers will be as add-ons to existing super-computers to resolve certain types of NP-Complete headaches that regular math can't simplify yet. At best they will someday be an add-on to your PC; but they will never replace the digital computer.~

If you want more info, check out http://www.qubit.org, it's got some decent tutorials.

I have seen many posts here that disregard the serious technical limitation imposed by classical computing by just saying 'Engineers will solve it, they always do'. That is like saying that faster than light travel is only an engineering problem. New computing paradigms are needed. Most predictions says that most of us will witness Moore's Law fail due to quantum mechanical and thermodynamical reasons. Instead of blindly pretending that the engineers will magically solve the problem it would be more proactive to start learning more about the prospects the next generation of technologies. We need to think, not to hope for something magical to happen.

read up on quantum crypto.

Crop cylinders

First, I'd like to point out that quantum computation and quantum encryption are two almost completely separate concepts. Quantum encryption is based on the fact that quantum states cannot be measured without altering. The most common example is the polarization of a photon, but it will work for any quantum state, so long as there exist, effectively, two unique states that can transmit the data.

Quantum computation, however, is much more complex and much more interesting. Quantum computers are based on the concept of quantum entanglement, the ability of a quantum state to exist in a superposition of all of its mutually exclusive states: It's a 1 and a 0. However, this is not as easy to use as one might think. While it's true that if you have n quantum logic gates you have the ability to input 2^n data values simultaneously (as opposed to only 1 piece of data if you have n digital logic gates), this is not going to be the end of classical computing for a few reasons. First, quantum computers have to be perfectly reversible. That means for every output there's an input and vice versa. And there has to be no way of knowing the initial states of the data. You don't process data, you process probabilities in a quantum computer; if you know exactly what any one value is throughout the computation, you can find out all of the values: the superposition ends and you're stuck with a useless chunk of machinery. This means YOU CAN ONLY GET ONE RESULT FROM ANY QUANTUM COMPUTATION, THE END RESULT. You can't see what the data in the middle is or the computer becomes useless. (Landauer's principle makes heat loss data loss. When your processor gets hot, it's losing data. If the same thing happened to a quantum computer, it wouldn't be quantum anymore.) Decoherence is what happens when you randomly lose data to the environment by design, not by choice, and the superposition ends. This is bad for Q.C. Oh, and quantum computers can only do *some* things faster, like prime factorization and discrete logarithms. Not multiplication or addition. Plus, the circuits that would do basic arithmetic would be bigger and slower than what you've currently got.

So what does this all mean? It means that quantum computers are going to provide some advantages (real quick big number factorization), and some disadvantages (that whole RSA standard). The most realistic initial use of quantum computers will be as add-ons to existing super-computers to resolve certain types of NP-Complete headaches that regular math can't simplify yet. At best they will someday be an add-on to your PC; but they will never replace the digital computer.~

If you want more info, check out http://www.qubit.org, it's got some decent tutorials.

or this

Quantum computing DOES exists. You can read up on the current state of things here. Quantum computing has been demonstrated with only a few qubits, which is all you need for quantum cryptography.

Well, I wasn't too sure, so I dug up some links to try and help myself and others understand this:
http://research.microsoft.com/~gottesma/QKD.html
http://www.qubit.org/intros/crypt.html
http://www.ecst.csuchico.edu/~atman/Crypto/quantum /quantum-index.html

The last link is particularly +1 insightful about the basics of quantum cryptography.

I found a site that explains why classic cryptography suffers when compared to the benefits of quantum cryptographic methods.

The site is located at http://www.qubit.org/intros/crypt.html, and is part of the Center for Quantum Computation (Oxford University).

Here's a nice basic overview of QC from the site mentioned above: "While classical cryptography employs various mathematical techniques to restrict eavesdroppers from learning the contents of encrypted messages, in quantum mechanics the information is protected by the laws of physics. In classical cryptography an absolute security of information cannot be guaranteed. The Heisenberg uncertainty principle and quantum entanglement can be exploited in a system of secure communication, often referred to as "quantum cryptography". Quantum cryptography provides means for two parties to exchange a enciphering key over a private channel with complete security of communication."

Linux > Help > About

Quantum entanglement

Teleportation

Quantum entanglement

Teleportation

http://www.qubit.org/intros/comm/comm.html

(Centre for quantum computation)

However, I'm not one to suggest it would be undefeatable!

how fast, really, would a semi-decent quantum processor be, compared to a semi-decent silicon one? (This may seem like an ignorant or even trolling question, so I apologise in advance)

Yes, it does sound uninformed, and the fact that you're asking it probably means you really know rather little about what quantum computers are really about. The paradox about quantum computers is that they don't need to be faster than their classical counterparts, and in fact, the most of the really promising methods, like the NMR bulk-spin resonance techniques for instance, are far, far slower. These methods based on nuclear spins have clock rates that are measured in kilohertz. Yes, mere thousands of cycles per second. If you use a quantum computer to do the same things a classical computer does, in the same way, you can expect no real improvement. The real advantage in using these computers, which is what makes such a computer "faster" than its classical counterparts is the new paradigm of computing the quantum models of computation allow: that of performing computations on superposed states.

For instance, if you had a register that contained 256 qubits, placed them in an equal superposition of 1 and 0, and performed some calculation on that register, you will have potentially produced 2^256 results, 10^77 or a hundred million million billion billion billion billion billion billion billion results, which is more results than the number of sub-atomic particles in the visible universe! Of course, once you measure your qubits you only get one of these innumerable results, but there are more subtle ways of measuring the qubits that will give you information common to all of the results. That's what all of these algorithms for quantum computers are about.

Essentially, if you had 256 qubits each running at 1 kHz, you would have 10^77 processors running at 1 kHz! Now wouldn't that be faster than any computer in the world if you could use it properly? It's like having a slow computer for every sub-atomic particle in the universe! What's needed now are algorithms that try to find structure in various problems that can exploit this sort of parallelism.

Shor's algorithm, for instance, is able to factor integers and compute discrete logarithms in arbitrary finite fields in O(n^2) time, by using a special technique (the quantum Fourier transform) to cause the results we aren't interested in to interfere destructively and so won't be measured when our superposition collapses. Grover's algorithm, which does unordered searches in O(sqrt(n)) time, leverages quantum parallelism in a similar way.

The real upshot, and a likely SF novel plot that involves quantum computers, comes from the fact that all public-key cryptography in widespread use today depends on the factoring (RSA) and discrete log (El Gamal and elliptic curve techniques) problems. These problems are thought to be intractable using a classical computer, but with Shor's algorithm and a large enough quantum computer, perfectly feasible. Obviously, no one has yet made a quantum computer with more than a handful of qubits (I believe seven qubits is the world record, meaning they could theoretically factor the number 126!), so these schemes are still quite secure. Other practical problems plague implementors. But if someone, somewhere, dreamed up a way to make quantum computing practical (i.e. making a quantum computer with thousands of qubits that could perform calculations stably), all public-key cryptography would fall apart. Whoever invented such a device could potentially break the root certificates of Verisign and other CA's, compute private keys, impersonate every e-commerce site in the world, read all PGP or S/MIME-encrypted email, forge all kinds of digital signatures, create bogus international banking transactions, and so on and so forth. Grover's algorithm would also increase the range of keys that can be feasibly brute forced for symmetric crypto (how much exactly depends on how fast your quantum computer is). Naturally, it would be a device intelligence agencies all over the world would kill to obtain. Ever see Sneakers?

If you're looking for more in-depth information that you can understand without a graduate degree in both physics and computer science (the way most of the preprints on lanl.gov tend to be), you can start by looking here.

That's presuming you have a known plaintext. That's usually not too hard to engineer, but with careful implementation, it should actually be very hard.

That's presuming you have a known plaintext. That's usually not too hard to engineer, but with careful implementation, it should actually be very hard.

That's presuming you have a known plaintext. That's usually not too hard to engineer, but with careful implementation, it should actually be very hard.

Quite a lame article, IMO.

The article fails to make any real points. It's merely a PR article for HP and MIT.

Unlike classical bits, the qubit can be not just 0 or 1 but a superposition of both, in differing proportions.

Um...wrong. The qubit can be in the 0 or 1 state, but can also be both at the same time, and have varying rotations. Which is what makes it immpossible for us to decode them. It is the multiple state position that is what is interesting to us, and what does the parallel computing. We just don't know how to utilize it just yet. There have been various articles. Quibit.org is a great place to start reading up on this stuff. The IBM Almaden has a nice article that will actually tell you something useful.

First, I'd like to point out that quantum computation and quantum encryption are two almost completely separate concepts. Quantum encryption is based on the fact that quantum states cannot be measured without altering. The most common example is the polarization of a photon, but it will work for any quantum state, so long as there exist, effectively, two unique states that can transmit the data.

Quantum computation, however, is much more complex and much more interesting. Quantum computers are based on the concept of quantum entanglement, the ability of a quantum state to exist in a superposition of all of its mutually exclusive states: It's a 1 and a 0. However, this is not as easy to use as one might think. While it's true that if you have n quantum logic gates you have the ability to input 2^n data values simultaneously (as opposed to only 1 piece of data if you have n digital logic gates), this is not going to be the end of classical computing for a few reasons. First, quantum computers have to be perfectly reversible. That means for every output there's an input and vice versa. And there has to be no way of knowing the initial states of the data. You don't process data, you process probabilities in a quantum computer; if you know exactly what any one value is throughout the computation, you can find out all of the values: the superposition ends and you're stuck with a useless chunk of machinery. This means YOU CAN ONLY GET ONE RESULT FROM ANY QUANTUM COMPUTATION, THE END RESULT. You can't see what the data in the middle is or the computer becomes useless. (Landauer's principle makes heat loss data loss. When your processor gets hot, it's losing data. If the same thing happened to a quantum computer, it wouldn't be quantum anymore.) Decoherence is what happens when you randomly lose data to the environment by design, not by choice, and the superposition ends. This is bad for Q.C. Oh, and quantum computers can only do *some* things faster, like prime factorization and discrete logarithms. Not multiplication or addition. Plus, the circuits that would do basic arithmetic would be bigger and slower than what you've currently got.

So what does this all mean? It means that quantum computers are going to provide some advantages (real quick big number factorization), and some disadvantages (that whole RSA standard). The most realistic initial use of quantum computers will be as add-ons to existing super-computers to resolve certain types of NP-Complete headaches that regular math can't simplify yet. At best they will someday be an add-on to your PC; but they will never replace the digital computer.~

If you want more info, check out http://www.qubit.org, it's got some decent tutorials.

First, I'd like to point out that quantum computation and quantum encryption are two almost completely separate concepts. Quantum encryption is based on the fact that quantum states cannot be measured without altering. The most common example is the polarization of a photon, but it will work for any quantum state, so long as there exist, effectively, two unique states that can transmit the data.

Quantum computation, however, is much more complex and much more interesting. Quantum computers are based on the concept of quantum entanglement, the ability of a quantum state to exist in a superposition of all of its mutually exclusive states: It's a 1 and a 0. However, this is not as easy to use as one might think. While it's true that if you have n quantum logic gates you have the ability to input 2^n data values simultaneously (as opposed to only 1 piece of data if you have n digital logic gates), this is not going to be the end of classical computing for a few reasons. First, quantum computers have to be perfectly reversible. That means for every output there's an input and vice versa. And there has to be no way of knowing the initial states of the data. You don't process data, you process probabilities in a quantum computer; if you know exactly what any one value is throughout the computation, you can find out all of the values: the superposition ends and you're stuck with a useless chunk of machinery. This means YOU CAN ONLY GET ONE RESULT FROM ANY QUANTUM COMPUTATION, THE END RESULT. You can't see what the data in the middle is or the computer becomes useless. (Landauer's principle makes heat loss data loss. When your processor gets hot, it's losing data. If the same thing happened to a quantum computer, it wouldn't be quantum anymore.) Decoherence is what happens when you randomly lose data to the environment by design, not by choice, and the superposition ends. This is bad for Q.C. Oh, and quantum computers can only do *some* things faster, like prime factorization and discrete logarithms. Not multiplication or addition. Plus, the circuits that would do basic arithmetic would be bigger and slower than what you've currently got.

So what does this all mean? It means that quantum computers are going to provide some advantages (real quick big number factorization), and some disadvantages (that whole RSA standard). The most realistic initial use of quantum computers will be as add-ons to existing super-computers to resolve certain types of NP-Complete headaches that regular math can't simplify yet. At best they will someday be an add-on to your PC; but they will never replace the digital computer.~

If you want more info, check out http://www.qubit.org, it's got some decent tutorials.

This article would lead you to believe that Quantum computing will provide a linear speed up to most algorithms. In fact only a very limited set of algorightms actually benefit from Quantum Paralellism. Peter Shor's algorithm for fatoring large numbers is significant not becasue it's terribly useful, but because at the time it was the only thing useful that had yet been devised for a quantum computer. Quantum computers are massively parallel, but because of some of the tricky laws of quantum mechanics, you can only read one result from the parrallel computation (The whole bit about observation causing wave functions to collapse.).

If you're really wantining to read more on Quantum Computing and Quantum Mechanics in general check out the Oxford Centre for Quantum Computation (David Deutch and Artur Ekert have done some really significant stuff) and read In Search of Schrodinger's Cat by John Gribben.

I'm currently doing research in a subset of quantum algorithms (and have worked as a research assistant in another area of quantum mechanics). They're pretty cool, but you shouldn't get your hopes up for them making the latest kernal hack run faster.

Introductory articles on quantum computation>

First, I'd like to point out that quantum computation and quantum encryption are two almost completely separate concepts. Quantum encryption is based on the fact that quantum states cannot be measured without altering. The most common example is the polarization of a photon, but it will work for any quantum state, so long as there exist, effectively, two unique states that can transmit the data.

Quantum computation, however, is much more complex and much more interesting. Quantum computers are based on the concept of quantum entanglement, the ability of a quantum state to exist in a superposition of all of its mutually exclusive states: It's a 1 and a 0. However, this is not as easy to use as one might think. While it's true that if you have n quantum logic gates you have the ability to input 2^n data values simultaneously (as opposed to only 1 piece of data if you have n digital logic gates), this is not going to be the end of classical computing for a few reasons. First, quantum computers have to be perfectly reversible. That means for every output there's an input and vice versa. And there has to be no way of knowing the initial states of the data. You don't process data, you process probabilities in a quantum computer; if you know exactly what any one value is throughout the computation, you can find out all of the values: the superposition ends and you're stuck with a useless chunk of machinery. This means YOU CAN ONLY GET ONE RESULT FROM ANY QUANTUM COMPUTATION, THE END RESULT. You can't see what the data in the middle is or the computer becomes useless. (Landauer's principle makes heat loss data loss. When your processor gets hot, it's losing data. If the same thing happened to a quantum computer, it wouldn't be quantum anymore.) Decoherence is what happens when you randomly lose data to the environment by design, not by choice, and the superposition ends. This is bad for Q.C. Oh, and quantum computers can only do *some* things faster, like prime factorization and discrete logarithms. Not multiplication or addition. Plus, the circuits that would do basic arithmetic would be bigger and slower than what you've currently got.

So what does this all mean? It means that quantum computers are going to provide some advantages (real quick big number factorization), and some disadvantages (that whole RSA standard). The most realistic initial use of quantum computers will be as add-ons to existing super-computers to resolve certain types of NP-Complete headaches that regular math can't simplify yet. At best they will someday be an add-on to your PC; but they will never replace the digital computer.~

If you want more info, check out ahttp://www.qubit.org, it's got some decent tutorials.

I guess he never heard of Quantum Computation.

I'd like to play Quake 21 (or Doom 15) in one of those babies

The place to go is Oxford University, see here. Oxford is home to David Deutsch and Artur Ekert, two of the most seminal contributors to the theory of quantum computation.

A brief introduction to Quantum Cryptography Looks interesting... I wish I could find more info on the Los Alamos site about what they've done with crypto.

(Sorry about the double-post; Didnt think about what when I completed the subject line)

Unfortunately, since the task of creating workable and useful algorithms for quantum computers is still in its infancy, I very much doubt present day programmers will ever be able to sit in front on one and hack away at a piece of code. Quantum algorithms are very different from those we use in current computers.

See QUIC at CalTech or the Centre for Quantum Computation at Oxford for more information on quantum algorithms.

The significance of Quantum Computers in the field of Cryptoanalysis is that they work differently! For a "normal" computer the time taken to decrypt a PGP messages increases rapidly with the length of the message (was it exponentially?). So a 4000 bit key will not take 4 times as long to decrypt as a 1000 bit key, but many many times as long!

The Quantum Computer built by IBM however, does it in 1 (ONE!!!) step. So if they can scale it to several thousand atoms, your 4000 bit key is worth nothing... because it will still only take ONE step!!! The only thing they need is a computer with a register long enough to hold your key (4096 bit, possibly they need a bit more..). I imagine however, that this will be quite difficult and that our keys should be safe for the near future :)

If you wonder how PGP relates to finding the period of a function (which is what IBM found) have a look at this. I don't understand all the maths... but it seems someone has shown that finding the period of a function can be used to determine the factors of a large number, precisely the problem you face when trying to decrypt PGP!

It mentions that quantum computing will be incredibly useful for key-cracking, web-searching etc, but does anyone know what difference this will make to the end-user?

Also, how are we going to program these baby's? Surely current techniques, languages etc. will all be insufficient?

Questions, questions.

Also, while I'm at it, This is a good place for a quantum computing primer.

Get used to your e-mails being insecure. I know people are going to say "encryption", but think about this:

Before Quantum Cryptography becomes available, Quantum Computing will have arrived (many suggest within a few years) and it will render insecure most or all encryption methods using conventional computers. It has been proven that a quantum computer will be able to factor large primes (see reference in RSA's overview which, interestingly, predicts that quantum cryptography will be realised before quantum cryptoanalysis -- but they would say that, I guess ...).

(Find more about Quantum Cryptoanalysis on AltaVista.)

Sorry guys, but encryption will soon be a thing of the past (before it rises again in a different form on a different infrastructure). Bye, bye privacy, bye e-commerce, bye.

Learn to live with it.

(For the record: there is a different issue in some of the comments: should the Govt snoop your e-mails as a matter of routine? I don't think they should, any more than I think they should read all the postcards that are sent through the mail.)

---

"Where do you come from?"

Get used to your e-mails being insecure. I know people are going to say "encryption", but think about this:

Before Quantum Cryptography becomes available, Quantum Computing will have arrived (many suggest within a few years) and it will render insecure most or all encryption methods using conventional computers. It has been proven that a quantum computer will be able to factor large primes (see reference in RSA's overview which, interestingly, predicts that quantum cryptography will be realised before quantum cryptoanalysis -- but they would say that, I guess ...).

(Find more about Quantum Cryptoanalysis on AltaVista.)

Sorry guys, but encryption will soon be a thing of the past (before it rises again in a different form on a different infrastructure). Bye, bye privacy, bye e-commerce, bye.

Learn to live with it.

(For the record: there is a different issue in some of the comments: should the Govt snoop your e-mails as a matter of routine? I don't think they should, any more than I think they should read all the postcards that are sent through the mail.)

---

"Where do you come from?"

The big problem with chess is that the tree is VERY large- how big isn't known but estimates vary over a large range (see netchess and wolfram mathworld). There are certainly more chess positions than there are atoms in the universe, but the lines that lead to them are mostly worthless, so they don't matter and can be pruned away. Let's pick a tree size of 10^60-10^70 for arguments sake.

This is way beyond the scope of even distributed computing like SETI. It's usually reckoned that chess is unsolvable by brute force.

Normal computer techniques can handle about trees with about 10^20 positions or so, depending on how much hardware you can throw at it, and how long you wait.

However there are a couple of approaches that can reduce the exponent by a factor of 2 each in chess:

• Quantum computing
• Alpha-Beta pruning

As another poster noted, the current state of the art is 7 bits. You would need probably need 100s of thousands of bits to do chess. And the cycle time for current computers are measured in seconds rather than nanoseconds, but then again no optimisation for speed has been done AFAIK.

Finally it depends on the actual size of the chess tree. It may very well be there is a forced checkmate at say, move 40, in which case we would find it. But if there are only draws by repetition, under perfect play, the tree probably becomes impossibly large even with quantum computers.

Still, a search that said that there were no forced wins in say, the first 40 moves would be suggestive of a draw.

If anyone ever succeeds in creating a quantum computer, the storage problems problems will probably be solved. A state in the quantum computer can correspond to a superpositition of a lot af different states of the game. So n bits in a binary quantum computer may be able to describe 2^n states of the game. I haven't heard of any quantum chess algorithms yet, but using a good algoritm, the quantum chess computer should be able to do a kind of massive parallel computing. Here is a nice introduction to quantum computing I am not sure if quantum computing will allow us to solve chess completely, but at least it will probably lead to a great improvement.

IMHO Singh really does a fascinating job of writing this book. There are only two downsides to this otherwise-excellent book:

• A digressive chapter on the "breaking" of the heiroglyphics and Minoan Linear B; interesting, but didn't have much to do with codes.
• After spending the entire book showing how every "unbreakable" code was broken, Singh gets way too excited about the coming "unbreakable" code, Quantum Cryptography. Granted, it certainly seems secure, but it seems strange to me that he would herald this method as unbreakable when there barely exists a means of transmitting it in the first place.

--

Quantum cryptography is (assuming quantum theory is correct) an unbreakable cryptosystem. A basic primer of Q Cypto is here. This also gives details of how to implement Q. Crypto - test of quantum encrypted links of over 1km have already been demonstated: a far cry from "you can't develop [it] until you solve some general problems".

We need an "I am not a scientist" label (like IANAL) for posts like that one.

Check out these sites for more info on quantum computing

Qubit.org

Quantum computing and information at IBM

Try:

http://www.qubit.org

There are some good tutorials there.

See www.qubit.org for some interesting introductory articles.

So "What can QC do for AI?" Well, if humans are Turing machines, then in principle you can write down my algorithm and run it faster than my own brain can. On a quantum computer you could run my algorithm (ME essentially) not just a constant amount faster (more MHZ or a constant number of parallel processors) but quadratically faster and maybe even exponentially faster. It's not clear that "faster" would lead to more intelligence but I'd be surprised if you never ran out of time on an exam-- in those cases Faster would be smarter.

So, "What can QC do for Evolution?" We are in the proccess of decoding all 3 billion bits of the human genetic code. The specific arrangement of 3 billion bits came into existence through an evolutionary process over generations and generations of organisms (ultimately humans) on this planet. Now imagine we simulate that process. [We used to do this for fun in high-school] On a quantum computer entirely new ways of searching the available state space emerge-- once again we have a minimum of quadratic improvement on exhaustive search (for a QC) and exponential improvements are possible. That means my evolutionary simulations on a QC will be much richer and more interesting than your simulations on a classical computer.

Clearly, the simulation of evolution is not the same thing as evolution itself. My genetic algorithms will evolve more interesting behaviour than yours if mine run on a quantum computer-- that's the best --I-- can do. In "Quantum Evolution" a book that I haven't read McFadden tried to make a strong connection between QC and Evolution and previously I posted an Amazon link (lots of reviews there) that explores this QC-Evolution connection. I've read that book and I still can't explain the Many-worlds-evolution thing! Deutsch book is, for the most part, sound so maybe this new "Quantum evolution" thing is sound too. You can NEVER judge science by the press-releases. Look at this as an example. The journalists are actually talking about an experimentally verified technique (Quantum teleportation) that might be used to help us build a practical quantum computer. Did you get that from the article?

A. Wait.

This nanotech is a step in the right direction, for as far as I know circuts cannot be made any smaller than this (due to quantum uncertanty).

Actually this is a very good point, and one that could tie in nicely with another emerging technology, quantum processors.

Just grabbing the nearest link, you can read a fairly detailed exploration of the idea of quantum computers here. (With another bit of reading here)

Wouldn't it be interesting to consider pursuing the idea of quantum-level circuits, with perhaps some form of quantum circuit-control that takes full advantage of the nature of quantum matter?
I can imagine that the computing industry already has such vast momentum in terms of making things smaller and faster that the barrier of quantum mechanics will be one that is eventually broken, or at least bent to the will of computer manufacturers.

When that happens, we might see single-processor lateral processing as well as fully integrated quantum circuitry with near-instantaneous feedback (or even instantaneous, if quantum entanglement can be leveraged?).

Very interesting, and exciting stuff :)

B.

The richest ressource on quantum computing is the LANL e-print archive on quantum physics. A more structued site dedicated only to QC is the Oxford Centre for Quantum Computation. My own stuff can be found here.

The best has yet to come because with current technologies and knowledge, we can reach 1.6 GHz. But after that, the chip would melt anyway due to high temperature. 0.1 micron is the limit. Then we could multiply the numbers of processors but it's just a short term solution.

I've heard that HAL computer systems (working for Fujitsu) is working a prediction method to find data before it is calculated to increase speed. A little like the machine O (the Oracle) of Alan Turing.

There is also the MAJC computer of Sun that could be used to build a neuron network (like a machine B) to give more "smart" data processing.

Finally there are also the Quantum Computers that could change everything but that's almost science-fiction

All this information has been mainly taken from an article in LOGIN:

I used to be quite skeptical about unified theory, but then I read the Fabric Of Reality and I was just as lost, but even more interested.

It gives good justification to the thought that it is now impossible to know everything, however, it will be possible to understand everything... pretty freaking fascinating...

Bio and molecular level computing is next.. it will propagate and extend the life of Moore's law for another 10 years.

After that, quantum computing of course :)

http://www.qubit.org/

Please down-moderate the Coward's message, it's flatly wrong. First, QC isn't done on a chip, it uses a super-cooled row of ions in a vacuum sealed chamber. To factor a number with X bits, you need X in the row. The computation is performed by superposition of 2^X simultaneous quantum states, in theory taking only microseconds. Here's a link.

The way quantum computers work, it would take the same amount of time to crack 512 bits as it would to crack 56 bits, or any other value.

See, quantum computers don't do things serially like standard computers. They perform their operations on the entire data set all at once. It doesn't matter if the data set has 1 item or 1 billion items, it takes the same amount of time.

This is known as superposition. I don't know a terrible lot about the theory, but you can find out more at The Center for Quantum Computing. This Quantum Computing Tutorial is difficult to understand if you haven't done at least a little comp sci, and the one at qubit.org is better for people who've never heard of quantum computing at all.
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The way quantum computers work, it would take the same amount of time to crack 512 bits as it would to crack 56 bits, or any other value.

See, quantum computers don't do things serially like standard computers. They perform their operations on the entire data set all at once. It doesn't matter if the data set has 1 item or 1 billion items, it takes the same amount of time.

This is known as superposition. I don't know a terrible lot about the theory, but you can find out more at The Center for Quantum Computing. This Quantum Computing Tutorial is difficult to understand if you haven't done at least a little comp sci, and the one at qubit.org is better for people who've never heard of quantum computing at all.
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A book suitable for laymen (i.e. no math/physics background necessary) that covers this is The Fabric of Reality by David Deutsch, one of the pioneers of quantum computing mentioned in the article. See here.