Several Quantum Calculations Combined At NIST

Al writes "Researchers at the National Institute of Standards and Technology (NIST) have demonstrated a crucial step toward building a practical quantum computer: multiple computing operations on quantum bits. The NIST team performed five quantum logic operations and 10 transport operations (meaning they moved the qubit from one part of the system to another) in series, while reliably maintaining the states of their ions — a tricky task because the ions can easily be knocked out of their prepared state. The researchers used beryllium ions stored within so-called ion traps and added magnesium ions to keep the beryllium ones cool and prevent them from losing their quantum state." In related news, another reader links to an Australian study indicating that quantum computers "can continue to work perfectly even if half their components, or qubits, are missing."

Comments

Re:This may be slightly off-topic, but

[jpmorgan]

Typically with these searches you know the answer you want, and you're interested in which input gives you that answer (the inverse problem). An important caveat about Grover's algorithm is that, while it's significantly faster than classical unordered search, it's still non-polynomial.

Re:Begs the Question

[jpmorgan]

That's a horribly misleading summary. Quantum computation is plagued with error... the same thing occurs in classical scenarios but we have error correction schemes to deal with that (for example, error correcting codes). Analagously there's quantum error correction which lets you recover your quantum information after corruption, however previously it was fairly limited in capability. The new research is a way to improve quantum error correction, so that the original information is recoverable after much more substantial corruption than was possible before.

Re:This may be slightly off-topic, but

[FooAtWFU]

You might check it with a classical-computing algorithm. For NP problems, verification of the answer is often substantially faster than computing the answer itself.