Researchers Create Silicon-Based Quantum Bit

angry tapir writes "Researchers at the University of New South Wales in Australia have created the world's first working quantum bit based on a single atom in silicon. The research team was able to both read and write information using the spin, or magnetic orientation, of an electron bound to a single phosphorous atom embedded in a silicon chip. In February, UNSW researchers revealed they had successfully created a single-atom transistor using a single phosphorous atom in a silicon crystal."

Comments

Useful links

[hweimer]

Actual research article

Wikipedia article on the architecture proposal

Bit not a Qubit

[Big Hairy Ian]

All this demonstrates is the ability to store 1 bit of information at the atomic level not a Qubit which can be in multiple states at once due to quantum entanglement. This is like heralding the dawn of the computer age by promoting a mechanical calculator.

Re:Bit not a Qubit

[hweimer]

They show relatively clear Rabi oscillations, which are a definite proof of the quantumness of the evolution of their system (which has nothing to do with entanglement). So, yes, this is a genuine qubit, albeit not a perfect one.

Re:Bit not a Qubit

[Anonymous Coward]

No, they've demonstrated a single Qubit.

TFS makes things mucky by mentioning single electron transistors too, which are a completely different beast.

The problem with quantum computing isn't demonstrating single qubits though. The problem is in getting a reasonable number in a superposition. Most I've ever seen in a QC that actually does computations is 7 qubits.

Just to get an idea of the scale we need, Shor's algorithm, the one which we could use to crack RSA encryption in polynomial time, needs 2*N qubits minimum. So to crack RSA1024 we'd need 2048 qubits all in a state of superposition.

I'm of the opinion adding more qubits to a superposition is going to be an exponentially hard problem.

Re:Bit not a Qubit

[js33]

... based on a grand total of seven data points, and not controlled for the amount of resources that went into achieving an ever-so-brief superposition of, so far, no more than 14 or 15 qubits. The article you linked is very appropriately and clearly not much more than a scientifically excited suggestion that the growing number of qubits is in an exponential trend, and a guess at what might happen if the assumed trend should continue. You've got nerve to say "History tells otherwise." "History" also tells us that AAPL's stock price has reached escape velocity, and it will never return to earth, because all the analysts tell us that soon we'll all be incredibly wealthy and lining up around the block to spend 30% of our income on a mortgage for our next iPhone. Not saying it's impossible, but in either case, past performance in no guarantee of future returns, as that author was careful to note.

Re:ONLY A BIT ??

[Anonymous Coward]

so did a single vacuum tube when that was first invented...

I have a question:

[mister.woody]

can you run linux on it?

Re:I have a question:

[jamesh]

can you run linux on it?

Nope. Linux requires at least a two bit computer to run.

Re:payback

[wonkey_monkey]

First Evidence of Quantum Tunnelling Slashdot Post Dismissed as Human Error.

Impressive when you consider...

[sykobabul]

... that the Core i7 processor containing 731,000,000 transistors weighs approximately 386 g. 731,000,000 Silicon atoms weighs roughly 34 fg (femtograms) - using Avogadro's Constant and assuming I did my calculation correctly. That's a pretty huge space savings, even if you were only using binary computation.

Re:ONLY A BIT ??

[Chris Burke]

A single vaccuum tube is an amplifier.

So's a single transistor.

Both become "bits" only when you choose to interpret their outputs as binary.