Qbits unstable: May Limit Quantum Computing

museumpeace writes "Netherlands Organiztion for Scientific Research provies a human-readable description of research into the stability of Qbits conducted at Leiden University. The bad news: " Much to their surprise they discovered that the coherence tends to spontaneously disappear, even without external influences." The whole story in physicist-readable form is in the June 17 Physical Review Letters by van Wezel, van den Brink, Zaanen [click abstract or huge PDF]. I am not buying any quantum computing startups 'til they nail this matter down...you can't build a computer if state information is going to evaportate in a second or less."

Comments

So what? ECC & refresh!

[redelm]

I'm hardly surprised at quantum instability. It's inherent in the beast. But it doesn't much matter iff QC has big enough advantages. Put Error Correcting Code on all the busses and storage cells. Plus checkbits on the calcs as AFAIK is done today on P6/K7+ CPUs.

The real question is how deep do you need to make the ECC. That depends on error rate, my guess is Hamming 64+8 ECC will do.

Re:Nonsense.

[MrScience]

That's the problem with quantum computers. Their uptime has no negative impact on you... until you start to actually observe their stability.

vacuum tubes

[KurdtX]

So what? Before vacuum tubes there really wasn't any way to save the state information on a magnetic charge (or whatever those things held) reliably, and then after years and years of using those, we got good and have been making the space to store a bit ever smaller.

This is still experimental, so of course it's not consumer ready; ENIAC was built in 1946, and we're not even there yet. I'm sure there are folks on Slashdot who will never get to use a quantum computer first-hand, which sounds depressing, but that's how far off we are. Everyone just sit back and relax for a while on this one....