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First Quantum Byte Created
gila_monster writes "Juice Enews Daily is reporting that the Institute of Quantum Optics and Quantum Information at the University of Innsbruck in Austria has created an entanglement of eight quantum particles, yielding a quantum byte or 'qubyte,' or eight qubits. The formal paper was published in the December 1 issue of Nature. A qubyte with eight ions provides a computing matrix of 65536 mostly independent elements. No word in the article about whether they were able to actually use the qubyte for computing."
No word in the article about whether they were able to actually use the qubyte for computing
I think we can be sure that if somebody had unlocked the secret of quantum computing there's a chance they'd say so at some point.
Wasn't there some news recently that the so called quantum bits could be read without disturbing their state.
Which would either break quantum theory, or would mean they are just fabricated bits of information and not quantum bits at all.
The article was here
liqbase
... build a Linux Box 40 Qubits in size....
EMail: 0110001101100010010000000110001101110010 0110000101111010011011100110000101110010 0010111001100011011011110110
I was born in 1983, but now I can re-experience even advances in computing that happened in the seventies and before! Cabinet-sized hard-drives that hold a couple of megabytes? Quantum computing is at A FEW QUBITS! I doubt many people here lived through the ENIAC (and realized what it meant at the time), but that's exactly what my grandchildren will be hearing from me. Granson, back in my day we had EIGHT QUBITS! Not qubytes, QUBITS, sonny boy, eight of 'em. Like this: one, two, three, four, five, six, seven, eight. Total. And that was state of the art. It was a research demonstration! And we liked it!
"There is a world market for 4, maybe 5 quantum computers."
"512 kiloqubytes outta' be enough for anybody!"
Etc, etc, etc. WHOOOHOO!!! I was there at ground zero, baby!!! In ought six!!!!
What do you mean ought-six, grandpa? "I mean 2006, granson".
"Whoa! When were you born?"
"I was born in the LAST MILENNIUM, GRANSON"
"Did they have cars?"
"Just road ones."
"What about Google?"
"yeah, but it wasn't like today. Man I wish I'd have held on to that stock tho'..."
You understand this wrong.
A qubit indeed can have one of a continuum of states. For example, if you think of the photon polarisazion, each linear polarization direction corresponds to a distingt state, and then there are the circular and elliptic polarized states as well. Indeed, you can map the states of a qubit onto a sphere (embedded in ordinary 3D space), which is called Bloch sphere. Every point of that sphere corresponds to a (pure) state of the qubit. (Note that the Bloch sphere is not the Hilbert space, but for single qubits, it's IMHO much easier to understand things in the Bloch sphere picture)
Now if you measure, you basically choose a direction on that spere, and you get just one of two results. e.g. if you think of the sphere as Earth's surface, and let's assume you have chosen the direction of the Earth's rotation axis for measurement, then if the state of the qubit (before measurement) is actually the North Pole, you get with certainty one result (which, for obvious reasons, I'll call "North"), and if the state is the South Pole, you get with certainty another result (which I'll now call "South"). However, even if the state is something else, your measurement will never give anything but "North" or "South". The probability to get "North" grows the closer the state is to the North Pole, and equivalently for the South Pole. If the state is at the equator, the probability of getting North or South is the same, i.e. the result of your measurement is completely unpredictable.
Now the funny thing is that after you measured North or South, for an ideal quantum measurement, the state actually is the corresponding Pole, no matter what it was before.
If you map the states described by the article with the Bloch sphere, and say you map the states 0 and 1 to the North and South pole, then the states you named `0 and `1 would be two antipodal states on the equator, say on the zero meridian and on the 180 degree meridian (unlike in the hilbert space, the directions now are not in 45 degrees, but actually orthogonal). That is, if the state is `0 or `1, then any measurement in the north-south direction will give completely unpredictable results. Of course if you choose the direction of the `0 and `1 states (I'll call that the equatorial direction from now on), then those states will create a predictable result, while the North and South pole states will get completely unpredictable results.
Now the nice thing for encryption is that if you don't know if the state was prepared in the North-South direction or the equatorial direction, there's no way for you to know if what you got for a measurement is a prepared state, or just random garbage. Moreover, since measuring in the wrong direction changes the original state (and therefore destroys the information which was originally in there), you'll be able to notice if someone tries to eavesdrop your connection.
The Tao of math: The numbers you can count are not the real numbers.