4 ms·

> There's a discontinuous boundary? That's news to me. I too find it unlikely that there is such a discontinuity. Quite a large number of physicists (and quan

> There's a discontinuous boundary? That's news to me. I too find it unlikely that there is such a discontinuity. Quite a large number of physicists (and quantum computing people) seem to speak as if there is one. > Finally, decoherence has seen plenty of study I get the impression that decoherence is treated as merely a problem for technicians working on experimental apparatus, or an engineering issue to be dealt with on the road to quantum computation. Are there any results on fundamental limits to the degree of entanglement in a system? We've been trying to get that damn cat into superposition for ~85 years now, with no luck.

im3w1l 6y ago
> Quite a large number of physicists (and quantum computing people) seem to speak as if there is one. The reason they seem to speak that way is because they are being a little sloppy for the sake of brevity. The physicists all understand that there is a blurry boundary. There is an amusing instance where there was a similar confusion though: the soft diffraction limit was mistaken by many for a hard one. So super-resulution came as a bit of a shock.
lmm 6y ago
> I get the impression that decoherence is treated as merely a problem for technicians working on experimental apparatus, or an engineering issue to be dealt with on the road to quantum computation. Are there any results on fundamental limits to the degree of entanglement in a system? We've been trying to get that damn cat into superposition for ~85 years now, with no luck. We've been setting records for bigger and bigger superpositions every few years - apparently we're up to 2000 atoms now. There's no reason to suspect there's a fundamental limit, any more than there's a fundamental problem that prevents nuclear fusion from working. That doesn't mean the engineering isn't devilishly hard, maybe even impractical (if it gets literally exponentially harder to maintain more and more particles in superposition), but it's not a fundamental physics issue.

im3w1l 6y ago

> Quite a large number of physicists (and quantum computing people) seem to speak as if there is one. The reason they seem to speak that way is because they are being a little sloppy for the sake of brevity. The physicists all understand that there is a blurry boundary. There is an amusing instance where there was a similar confusion though: the soft diffraction limit was mistaken by many for a hard one. So super-resulution came as a bit of a shock.

lmm 6y ago

> I get the impression that decoherence is treated as merely a problem for technicians working on experimental apparatus, or an engineering issue to be dealt with on the road to quantum computation. Are there any results on fundamental limits to the degree of entanglement in a system? We've been trying to get that damn cat into superposition for ~85 years now, with no luck. We've been setting records for bigger and bigger superpositions every few years - apparently we're up to 2000 atoms now. There's no reason to suspect there's a fundamental limit, any more than there's a fundamental problem that prevents nuclear fusion from working. That doesn't mean the engineering isn't devilishly hard, maybe even impractical (if it gets literally exponentially harder to maintain more and more particles in superposition), but it's not a fundamental physics issue.