Software Designs Quantum Experiments

[Hornbein]

Anton Zeilinger of the University of Vienna was trying to design experiments to produce certain quantum states and wasn't having much luck doing it. "I realized I was just guessing," he said. So why not have a program do that guessing. It can try a million guesses. So he did.

While the resulting experiments are simple, no human seems to be able to "understand" them. That is, they can check and see that the math is correct, but can go no further than that.

It's not really surprising. Those experienced in quantum mechanics often say that intuition gets in the way. They try to concentrate on the math. Since the computer has no intuition to mislead its guesses, it has an advantage.

Zeilinger was working on entanglement of three photons, which evidently is exceptionally weird.

"Young man, in mathematics you don't understand things. You just get used to them." -- John von Neumann

http://physics.aps.org/articles/v9/25

 

[DrClaude]

This is nothing new for people who have been working with optimal control. Actually, I quite disagree with the statement

Quantum theory verifies that Melvin’s arrangements should work, but that doesn’t mean it's easy to understand why. “I still find it quite difficult to understand intuitively what exactly is going on,” Krenn says. Such a lack of understanding, even for experiments with only a few components, “is unique to quantum physics,” says Krenn.

I do not think it is in any way unique to quantum physics, but would happen with any sufficiently complex system.

Just to be clear, I think that Krenn et al. did wonderful work. But it is annoying when an existing technique is introduced in a field and people behave as if they had just invented sliced bread, while researchers down the hallway have shelves full of pre-sliced loaves

 

[Demystifier]

... for experiments with only a few components ...

Actually, I quite disagree with the statement
... would happen with any sufficiently complex system.

I think the question here is whether systems with only a few components can be called sufficiently complex.

 

[DrClaude]

I think the question here is whether systems with only a few components can be called sufficiently complex.

I was talking about the complexity of the system being controlled. But I agree that small quantum systems are incredibly more complicated than any similar-sized classical system.