I wrote this essay for a science writing contest/school about quantum computing. It's a little long for a forum post, but I think I put a lot of information in there. Enjoy!

Moore’s Law states that every 18 months, the number of transistors in a computer chip doubles, thereby increasing the speed of the computer (Arthur, 2005). In order for computer chip manufacturers to fit all of the extra transistors, the transistors themselves must become exponentially smaller. However, there must be a limit: Transistors cannot keep shrinking in size forever, and some scientists estimate that this limit will be reached sometime between 2010 and 2020. At such small sizes, electrons will begin leak out of the circuits (Arthur, 2005). So what does this mean for computers? Will they just stop becoming faster and effectively halt the progress of technology? The short answer is no.

Recently, scientists have been studying and developing a new kind of computer that works at the quantum level. Instead of having bits made of transistors, quantum computers have quantum bits (qubits) which can be made from almost any particle. The favorites so far have been atoms, photons, and electrons (Gomes, 2005). Traditional bits, those that are used widely today, can store either of the values 1 and 0. However, because of the strange things that happen at the quantum level, qubits can store either the value 1, the value 0, or both of those values at once. This combination of two values is called a “superposition,” and physicists say that (Arthur, 2005). In theory, this means that the qubits are in every possible binary configuration—at the same time. (Arthur, 2005).

This ability to hold many values at once in just a handful of qubits is what makes quantum computing so special. The power that quantum computers would have both frightens and excites people in many fields. One of the most directly affected fields would be data encryption. Right now, data encryption is based on multiplying extremely large prime numbers (Arthur, 2005). The idea behind this method is that it would take centuries to factor the resulting numbers on a modern computer because of the inefficiencies of even the best factoring algorithms. However, the superpositions of quantum computers allow them to use special algorithms to factor large numbers extremely quickly. This makes it seem like quantum computing would be bad for people who rely heavily on encryption. However, because of another special property of qubits, a more powerful technique is available.

Quantum cryptography, a new idea in data encryption that seems to fit in well with quantum computing, utilizes an idea called “quantum entanglement.” This says essentially that it is possible for two or more qubits to become “entangled,” so that anything that effects one will effect the other, too (Begley, 2005). The application for quantum cryptography is as follows: Person 1 has two sets of photons which are entangled with each other and contain an encryption key. Person 1 then sends one set to person 2. If the photons make it safely to person 2, then person 2 can get the key and decrypt the data. However if they are intercepted, then the photons that person 1 has will be disrupted and no longer be useful (Begley, 2005). Because of this, quantum encryption is much more secure than current methods of encryption. In fact, it is nearly impossible to hack.

So why has this not been done yet? Well, it is not as simple as it sounds. Though a full-scale quantum computer is theoretically possible, it would require thousands of qubits, and so far we lack the technology to achieve such a feat (Cho, 2005). However, quantum computers have been made on a very small scale. IBM made several machines between 1998 and 2001 with three, five, and then seven qubits. These have been able to make simple calculations such as factoring small, two-digit numbers (Arthur, 2005). Impractical as these machines are, they mean progress. Unfortunately, there are other limiting factors: A qubit’s ability to store information deteriorates over time. Furthermore, the smaller the qubit, the quicker it decays. (“Obstacle for Quantum,” 2005).

For all this, though, the biggest problem with quantum computers right now is mostly that we just have not thought of a good solution yet. After all, what it really boils down to is a new idea. Thousands of things so far in human history have been labeled “impossible,” but then someone thought up an ingenious idea and now many “impossible” things are taken for granted: Computers, television, even electricity. So it is really not too far-fetched to say that quantum computers will be relatively commonplace in the near future, in fact it might be wrong to say that they will not. We only need for someone to wake up one day, shout “Eureka!” and build a practical quantum computer. Until then, we think.

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If his whole post was an essay, shouldn't it all have been within quote tags?

IF you read far enough into computing in general, you'll see that having more powerful, spacey enabled computers in a compact enviroment, isn't too far away. I think by 2010 everyone wont have changed that much, but things will be alot smaller.

Lol, I wonder how the person who shouts Eureka when he wakes up and then a magical quantum computer is going to happen.

Great article, its always nice to know how the future is going to turn out, though its still a bit confusing, the part where it is a 1 but then its a 0 and then its both? I read this article somewhere else about a week ago but it was really really confusing. It said it had to do with teleportation, and that scientist were already able to teleport bits and stuff within a computer. I dont know, I guess we will just have to wait and see how it all turns out. Cheers!

You know, I think Neils Bohr (not sure of the spelling, sorry), a brilliant physicst who had a lot to do with revolutinizing the physics of his time (I think we're talking early 1900s here...) had once told a student of his that if you don't feel dazed/giddy after a quantum physics lecture, you have not understood anything of quantum physics. According to Feynman, while only a few people get relativity right, no one has truly understood quantum mechanics completely.

So... join the club (a rather elite one, at that. )

lol you are wrong, in fact, quotation is a good way to make reference to another studies and works, so you respect the source of the information

Wow, thanks for that. I've never really understood quantom computing until reading that.

However, could you encypt using quantum computers to end with the same problem as we have now with it taking a long time to factorise large primes/other mathematic number used for the future of encypting

Take what keysmaker said, add the fact that everything that's not in quotes is my original text, and the fact that I asked a mod about whether posting an essay would be alright. But if you still want to argue...