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Light-based Quantum Circuit Does Basic Maths
Stochastism writes "In yet another small step toward realistic quantum computing Australian researchers have developed a light based 4-qubit quantum computer. It has already calculated the prime roots of fifteen, three and five. 'The quantum circuit pioneered by the Queensland researchers involves using a laser to send "entangled" photons through a linear optical circuit ... The Queensland research group acknowledged that the theorised code cracking ability of quantum computers may be why Australian quantum computer research is in part funded by a US government defence intelligence agency, the Defense Advanced Research Projects Agency (DARPA).'"
Seven! It does seven maths!
More importantly, can it run Crysis?
Fear the penguin.
1 qubit = 1 bit, I believe
I wonder if Moore's law will apply to the number of qubits within a quantum computer as well. A 1024 qubit computer within the next 20 years would be nice.
The similarity to bits only occurs once you open the box.
Until that point a cubit represents a dead cat.
liqbase
I was under the impression that we couldn't simply use PHOTONS as qubits - because while photons do have a quantum state, they get all...destroyed.
Of course, the article doesn't help.
Anyone?
Parse error! Parse error!
Sorry, wrong. Math and maths are both colloquialisms, and neither is more valid than the other. Just Britith vs American english tendencies, mostly.
http://www.answers.com/maths&r=67
Thanks fo the rant, though.
I, too, have already calculated the prime roots of fifteen, with nearly identical results. Where's my DARPA funding?
I've taken to just calling it just 'American' rather than English.
Q: What kind of room is it kept it?
A: A Qubicle
Q: How big is it?
A: About four Qubit meters.
Q: Qubit? Wasn't that an early arcade game with a little guy jumping around changing the quantum state of a bunch of Qubes?
I have OBVIOUSLY had too much Qaffeine.
Veritas patesco per quaestio questio. Truth is revealed through questions.
I once new a guy who could compute the prime roots of 15 in his head.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
Correction: Some non-native speakers of English are taught British English, not all. Moreover, British English has not been the standard worldwide for many years, so outside of Commonwealth countries and Europe, people do not, as a rule, gravitate towards British English.
And no, all this has nothing to do with which dialectic is better. It's just sociolinguistics. American English is the premier language of commerce and political power. It's also the medium of a huge amount of popular culture and marketing. Sooner or later, the prestige will shift elsewhere, just as it started to shift away from Britain after WW2. Sic transit gloria mundi.
We should also keep in mind that for some language groups, English s-plurals are particularly challenging, so the "maths" issue gets obscured by its similarity to a huge amount of genuine errors.
-- Wanted --
Schrödinger's Cat
Dead or Alive
Intron: the portion of DNA which expresses nothing useful.
-- Wanted --
Schrödinger's Cat
Dead and Alive
The Kruger Dunning explains most post on
Soon we will be able to test 2^N possibilities in 2N time, but my question is where does that information come from? There's a lot of hand-wavyness on how that actually happens...
Phenomena like superposition and entanglement are not fully understood from the metaphysical point of view, and there is some hand-waving about that. But the mathematics agrees perfectly with experiment, and that's all we need to know to put the theory to use.
One possibility is that we ask the 'computer' of the universe to do too much computation and end up in an infinite loop, crashed universe, 'dark' part of a mandlebrot-like fractal, etc.
Another possibility is that the 'computer' of the universe will simply abort operations that take 'too long', the quality of our simulation will degrade, and our complex quantum math will result in randomish results.
How do we know building a quantum computer won't break the universe? Well, the things that go on in a quantum computer are the same things that go on in ordinary matter all the time. A speck of dust consists of some 10^20 particles that continually interact with each other according to the same quantum-mechanical laws that govern the interaction of qubits used in integer factorization. Why should the universe care what purpose we use those interactions for?
And in the end, a size/time-N quantum computation can be simulated with 2^N space and in 2^N time on a classical computer (I might be wrong about the exact form of those expressions). Would the universe collapse if we run a quantum algorithm on a PC?
And then there is the possibility held by quantum researchers that somehow the universe can magically perform any amount of complex computation with no cost at all.
This isn't true. Quantum algorithms have real costs that grow with the size of the problem, just like on ordinary computers. (Concretely speaking, we can simulate them on classical computers in deterministic time.)
Who to go with, the military funded scientists working on a solid foundation of one of the most tested and proven physical theories mankind's best and brightest conceived of and developed with working models or a random blogger who can't get his head around the uncertainty principle.
Well, fair enough, Einstein himself quoted 'God does not play dice' on this very issue, before coming to terms with it. You might have the best of intentions but unfortunately you're off track. Regardless of what anybodies opinion is the quantum uncertainty model accurately predicts all available data, and theories that coincide with empirical evidence are useful and usable no matter how small or great an understanding we have of the underlying processes.
Come up with a simpler theory that fits all the data and I'll gladly accept your claims of crackpottery, otherwise open your mind a little and realise that regardless of a deeper understanding, if the math fits, we can do it, ergo quantum computing is not just feasible, but is already happening as we speak in labs the world over, like the one in TFA.
CRAP! 15 was my RSA public key!
The article mentions things called "prime roots." This is not a standard mathematical term. Rather, considering the context, quantum computing, and its most discussed potential application--quantum cryptography--it is likely that what was actually computed were primitive roots.
..., and modulo 5, this becomes 2, 4, 3, 1, 2, .... The first occurrence of 1 is for 2^4, hence k = 4 = 5-1.
For the sake of completeness, a primitive root of a prime p is an integer r such that the smallest positive value of k such that p divides r^k - 1 is k = p-1. For large primes, finding primitive roots is not a trivial task. For example, r = 2 is a primitive root of p = 5, since the positive integer powers of 2 are 2, 4, 8, 16, 32,