Schrodinger's Cat Closer To Reality?

Shipud writes "A group from the University of Oxford is proposing a scheme to achieve quantum superposition in a large object, according to Nature - not as large as Schrodinger's cat, but about ten-thousandth of a square millimiter, some 10^14 atoms. Quantum superposition is the phenomenon in which a photon passing through a beam splitter to takes two paths at once, inconceivable in the macroscopic world. William Marshall and co-workers suggest to mount a tiny mirror on a springy arm, so that the power of a single photon will be enough to oscillate it. When that photon is superposed, it transfers its superposition to the mirror, which will be quantum superposed: at two places at once. Wave particle duality has already been shown in Buckminster fullerenes, a 60 atom compound. Are we getting closer to quantum computers?"

Comments

Interesting!

[floydigus]

Quantum superposition is the phenomenon in which a photon passing through a beam splitter to takes two paths at once, inconceivable in the macroscopic world.

Whereas Slashdot is the phenomenon in which a sentence takes two paths at once.

Open the box and see

[Dancin_Santa]

Are we getting closer to quantum computers?

Maybe.

Canonical answer

[jolshefsky]

The question:

Are we getting closer to quantum computers?

The answer:

Yes and no.

Re:heating up counts as a measurement

[radtea]

This is a good point, but I'm sure the researchers have considered it. The limiting factor will be inelastic flexion of the cantilever, which can be made small in a number of ways, not least of which is keeping the amplitude of vibration small. Given that they're talking about setting the thing vibrating using the momentum transfer from a single photon, this shouldn't be a huge problem!

But it does bring up an important common misunderstanding that the headline of the article repeats: quantum effects have absolutely nothing to do with size and everything to do with complexity. A photon that passes through both slits of a double-slit apparatus demonstrates quantum effects on a scale of a fraction of a millimeter (the separation distance of the slits) and large multi-path interferometers of one kind or another involve photons that take paths that are tens of centimeters or more apart.

Size doesn't matter. What matters is the number of modes available, because interference between modes destroys our ability to observe quantum effects. Systems of many particles (particularly at higher temperatures) have so many modes available that the coherence time is extremely small, although even then we can under the right circumstances observe things like the Mossbauer Effect in which an entire block of material acts as a single quantum-mechanical entity.

--Tom

Re:Yeah...

[isaac]

I don't mean to be a spoil sport, but even if they accomplish superposition, we still have Heisenberg to consider, right?

I'm not sure. Maybe we do, and maybe we don't. We'll probably never know for certain.