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Quantum Computing Breakthrough in Japan
An anonymous reader writes "A research team funded by NEC and RIKEN, Japan's Institute of Physical and Chemical Research, are the first to demonstrate a Controlled NOT (CNOT) quantum gate. The CNOT gate when coupled with a rotational gate would create a universal gate. The universal gate would be the basis for quantum computing. ETA for the first quantum computers: 10 to 100 years." When quantum computers first come to fruition, the best part will be reminiscing about how terrible computers were "back in the day."
But that's really neither here nor there.
This black hole brought to you by Microsoft!
"And you thought we sucked before!"
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actually, no. the universe doesnt crash.. least not yet..
Then again, if you chart processor and memory usage, you will find that nothing will run Windows 2015
At least call it by its proper codename. It's called Longhorn, not Windows 2015
Have you tried Linux yet?
When quantum computers first come to fruition, the best part will be reminiscing about how terrible computers were "back in the day."
No, they'll still be terrible. They'll just be terrible really quickly.
Refuse to make a statement in your sig!
In a regular computer, data flows through "static" gates. In a quantum computer, the data (qubits) is stationary and the "gates" are in fact carefully crafted laser pulses (the article is not very specific about this particular CNOT gate though)
1-2 qubits is easy. More qubits are quite difficult to put together. That's why most of the current quantum computers barely do 10 qubits.
Errors are of analogical nature. Correcting them (with Q-ECC codes) is quite expensive - a more reliable qubit requires a couple normal qubits and gates (I say more reliable because the whole thing is probabilistic)
Quantum data is very "transient" - it cannot be copied. It can be teleported however (teleportation destroys the source). Storage is however difficult (keeping a superposition of qubits coherent for humanly-observable times is almost intractable)
A quantum computer can do an operation on 2^k superpositions at the same time (in other words, exponential work in constant time). Selecting the "right" answer from the superposition of 2^k results takes however 2^(k/2) (Lov Grover's algorithm) - so it's still exponential. This is one of the reasons quantum computers were not shown to be more powerful than regular ones (i.e QP != P) . Yes, Shor's factorization algorithm works in polynomial time on quantum computers, and is furthermore quite efficient, but factorization has been shown to be in P anyway (although the current "regular" algorithm is not efficient at all)
The Raven
Modern schemes wouldn't be necessary because quantum cryptography would become the standard and is proven to be unbreakable by the laws of quantum mechanics. Any interaction (malicious or otherwise) of a third party is noticable to the proper parties and the message/key transmission is just repeated until a clean send is achieved.
Here, here and google (of course) provide some good reading if you're interested
If You Drink, Don't Park, Accidents Cause People.
Recursion (n): See recursion
OTP works by having a completely random key that is as long as the data itself. It is then combined with the data in some way (say, for example, XOR) and reversed at the other end given the correct key.
The key (no pun intended) here is that there is no way to know when you have the correct key. With the XOR example, there exist keys that will produce every possible combination of output bits, and no way to tell which one is right. So trying to decrypt it is no different than generating random bit patterns the length of the data and seeing which output "looks right" - even looking for outputs that are valid English, you will encounter every possible sentence of the given data length.