Origin > How to Build a Brain > Quantum Computing with Molecules
Permanent link to this article: http://www.kurzweilai.net/meme/frame.html?main=/articles/art0171.html

Printable Version
    Quantum Computing with Molecules
by   Isaac L. Chuang
Neil Gershenfeld

By taking advantage of nuclear magnetic resonance, scientists can coax the molecules in some ordinary liquids to serve as an extraordinary type of computer.


"Quantum Computing with Molecules" is no longer available on KurzweilAI.net. Please click here for the article.
 Join the discussion about this article on Mind·X!

 
 

   [Post New Comment]
   
Mind·X Discussion About This Article:

you make it sound so easy
posted on 09/22/2001 12:12 AM by American__Jesus@hotmail.com

[Top]
[Mind·X]
[Reply to this post]

all this talk about a new information storing device which will replace the fundimental base of all code, the bit (1 or 0) sounds great, but quantom physics, thats something elese to me. Its made to sound simplified to the reader. SOmething like this would take billions and involve so many people, yet making these comps would be out of our tech right now and out of anyone's price range for the next century unless the market goes up, a lotttt, right, well we know the chances of that happening.
-chris
15

Re: you make it sound so easy
posted on 09/22/2001 6:13 AM by wness@ix.netcom.com

[Top]
[Mind·X]
[Reply to this post]

>the next century unless the market goes up, a lotttt, right, well we know the chances of that happening.

Yeah nearly 100%. Unless you think the end of the world is coming.

Not that I necessarily agree with you on the long-term prospects for exorbitant cost requirements for this tech.

Willie

Re: Quantum Computing with Molecules
posted on 05/22/2002 11:49 AM by tucci@ar-rtiste.com

[Top]
[Mind·X]
[Reply to this post]

For a parody of quantum computing, see:
www.ar-tiste.com/
qcomp_onion/jan2002/front_page.htm

Re: Quantum Computing with Molecules
posted on 11/13/2006 5:11 PM by William.Y

[Top]
[Mind·X]
[Reply to this post]

Factoring large digit numbers with quantum computers does have a major impact on encryption based security systems. With many of the cryptographic systems today such as the RSA depending on the difficulty of finding two prime factors of a number, making this task efficient will definitely weaken their security potential if not obsolete. However, I believe that new problems will always give rise to new solutions.

The power of a quantum computer depends on the number of qubits it is built on. At the moment I believe that the highest number of qubits in an experimental quantum computer ever constructed was around 7. This was done in 2000 at Los Alamos National Laboratory using only a single drop of liquid. With 7 qubits, this computer would be able to perform operations on 2^7 different numbers at the same time instead of just one on today's computers (not including multi-core processors). Of course, having around 7 qubits of processing power in a quantum computer won't be much of a threat to cryptography right now. But scientists predict that we would have a computer with 100 qubits within this decade. In addition, once a 1000 qubit computer is constructed, the security of many cryptographic systems will be broken. With 2^1000 different numbers being able to be operated on at a single time, and with the speed of today's computers being measured in MIPS (million of instructions per second), one could only imagine the computational power of such a computer. I am guessing that with this computer, the number of instructions that could be processed would be greater than 10^300 instructions per second. Of course I am being optimistic, but this is a possibility. Having a leap from 10 qubits to 100 in a quantum computer within this decade is not impossible. One problem in constructing such a large n-qubit computer is that all the operations using the quantum logic gates must be completed before the information inside the qubits decohere (as stated in the article). The more qubits in a qubit register that we want processed, the greater number of logic gates, and the greater the number of these gates, the longer it takes for the entire logic operation to be completed. There seems to be many research in speeding up the quantum gates by using different materials, and the results they are providing are quite promising. At the rate of advancements in computer science I definitely see the construction of a usable quantum computer happening within this century if not decade.

Now to the threat of cryptography brought up by quantum computers. Some of the methods invented for computer encryptions in the late 20th century was thought to require a few thousand years or so to break. This was of course proved wrong with the joint effort of many privately owned computers and/or organizations over the internet. An example of this is the cracking of the 56-bit Data Encryption Standard algorithm in 1999 by two companies working together (done in 23 hours). When an encryption like this is believed to be no longer secure, it seems that the best course of action is usually raising the number of bits in the encryption system thereby making it harder to crack. By the way the encryption most used on the internet today is the 128 SSL encryption method so I guess nobody has been able to crack this efficiently yet. With the introduction of quantum computers, the most obvious method in increasing or maintaining cryptographic efficiency would be to raise the number of bits as well. The increase would definitely have to make the encryption depend on more bits than the capacity of qubits in a quantum computer (maybe 2^1000 bit encryption, I think). Storing this number of bits may not be a problem either since the storage capacity of qubits would also be massive. To sum it up, I believe that we will see quantum computers within the early 21th century and that cryptography may not be at risk as some people believe.

Just a thought :)