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New Idea Could Lead to Quantum RAM
KentuckyFC writes to tell us that scientists in Italy and the US have designed a new method of retrieving information from quantum memory that could allow them to create "Quantum RAM". "Giovannetti's idea is to send the address down the branching tree of connections in such a way that it only affects one switch at a time. The first address qubit sets a switch at the first branching point to go one way or the other; the second qubit is sent that way and sets the switch at the next branching point, and so on. The total number of entangled quantum systems is smaller, and they are not so susceptible to interference, allowing information to be retrieved from memory intact."
Nothing in this really sounds like a new idea except that using this method would have some benefit on the quantum level. It's just a balanced binary decision tree implemented as a (quantum, in this case) circuit such that leaf nodes are stored data and addresses are qbit streams. Am I missing something?
What? Yes, they exist, so far not with much memory though. One was used in '04 to implement Shor's Algorithm to factor the integer 15 (or 2^4-1). I know, baby steps, but sometimes I forget the factors of 15 :-/
Apology to Ubuntu forum.
A theorem of quantum mechanics is that you can't perfectly copy a quantum state as that would allow you to measure the energy of one copy and the time of the other, thus violating the uncertainty principle. In practise what happens is that the two systems become entangled so that a measurement on one of them will instantly disrupt the state of the other. Thus your quantum UNIX would have the 'ln' command but not 'cp' ( 'cp -l' is ok ). Even more amusing is that this mandates that the disruption is non-deterministic. If it wasn't you could use it to transmit information and energy quicker than the speed of light, which is prohibited by relativity. So, if you thought lawmakers had trouble understanding how computers work, just wait until they get to deal with the question of who is liable for causing the de-coherence of a quantum system ( hint: you can't prove it unless you caused it ). Bring on the lawyers :P