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Baby Steps Toward Quantum Computers
Mz6 writes "In a step toward making ultra-powerful computers, scientists have transferred physical characteristics between atoms by using a phenomenon called entanglement, which Einstein derided as 'spooky action at a distance' before experiments showed it was real. Such 'quantum teleportation' of characteristics had been demonstrated before between beams of light. Teleportation between atoms could someday lie at the heart of powerful quantum computers, which are probably at least a decade away from development. Researchers using lab techniques can create a weird relationship between pairs of tiny particles. After that, the fate of one particle instantly affects the other; if one particle is made to take on a certain set of properties, the other immediately takes on identical or opposite properties, no matter how far away it is and without any apparent physical connection to the first particle." Reader starannihilator adds: "Physics Web provides a good graphic summary of the phenomenon, as well as a good technical article."
I'd have to say (not that I actually know) that there would be equal danger now from a solar flare crashing your computer as there will be on a quantum computer. But what the hell do I know? You should go ask Scotty.
But what cost? Only government would want new technology this fast, maybe your NSA, that around codebreaking.
Read journal when you are not understand
Not so much Analogue vs Digital but rather Serial vs Parallel.
:-)
In searial you do one instruction per peice of data. In parallel you try EVERY piece of data in one instruction.
Some problems are trivial in serial but hard in a parallel and other problems are trivial in parallel but hard in serial.
Simple Example:
Iterative calculation are great in serial but aren't that good in parallel as you can calcualte the second value till you have the previous value.
The Famous example:
The big thing that quantum computers will do is make parallel problems trvial. The big two being simulations and cryptology. Cryptology is only hard because you have to try so many different combinations. Quantum would allow you to try EVERY combination at a single time. This make encryption almost useless at any key length.
It's also usefull for simulations like ray tracing and vector maths where you have a complex eqation where you just have to run for every possible variable.
So ever is a single iteration takes 1 hour for a quantum computer instead of 100th of a second for normal computers it will change the world. Breaking a key 2048 bit key will take exactly 1 hour instead of million+ years. Rendering a frame will take 1 hour on a single computer instead of 4 hours on 1000+ computers.
That being said it would be useless for Word, Excel or Firefox
Imagine a quantum computer that does 5 Hz out perform a cluster that does 5 TeraHz.
Quantum computers aren't quite as powerful as you make them out to be. At the end of your algorithm, you have to perform a measurement, and each qubit when measured only gives you 1 classical bit.
It's been proven that quantum computers are no better than classical computers at sorting (both O(n log n), although they are better at finding something in an unsorted database (Grover's algorithm does O(sqrt(N)), instead of O(N) classically).
No one has proven that quantum computers are faster than classical computers for factoring. We just know of a fast algorithm for a quantum computer and not a classical computer. It's likely that quantum computers are much faster there, though.