[sciborg2]

The Quantum Conspiracy: What Popularizers of QM Don't Want You to Know

Interesting presentation, probably worth more to people with a better understanding of physics than I possess.

What I got out of it was that due to contradictions in QM either Many Worlds has to be true OR "we are our thoughts" and thus Idealism describes the true nature of reality.

[Phallus Pendulus]

I tend towards the "Many Worlds" explanation, although it's probably just another way to look at "Zero Worlds" (and thus, idealism).

For all I know, neither is accurate and both are just ways for our primate brains to look at something we can't really understand...

[sciborg2]

Well, apparently "realism" has been disproved? 

The Reality Tests

...A new way of understanding an already powerful theory is beginning to take shape, one that could change the way we understand the world around us. Do we create what we observe through the act of our observations?...

...The only assumption Leggett made was that a natural form of realism hold true; photons should have measurable polarizations that exist before they are measured. With this he laboriously derived a new set of hidden variables theorems and inequalities as Bell once had. But whereas Bell’s work could not distinguish between realism and locality, Leggett’s did. The two could be tested...

....The experiment wouldn’t be too difficult, but understanding it would. It took them months to reach their tentative conclusion: If quantum mechanics described the data, then the lights’ polarizations didn’t exist before being measured. Realism in quantum mechanics would be untenable...

...With eerie precision, the results of Gröblacher’s weekend experiments had followed the curve predicted by quantum mechanics. The data defied the predictions of Leggett’s model by three orders of magnitude. Though they could never observe it, the polarizations truly did not exist before being measured. For so fundamental a result, Zeilinger and his group needed to test quantum mechanics again. In a room atop the IQOQI building, another PhD student, Alessandro Fedrizzi, recreated the experiment using a laser found in a Blu-ray disk player.

Leggett’s theory was more powerful than Bell’s because it required that light’s polarization be measured not just like the second hand on a clock face, but over an entire sphere. In essence, there were an infinite number of clock faces on which the second hand could point. For the experimenters this meant that they had to account for an infinite number of possible measurement settings. So Zeilinger’s group rederived Leggett’s theory for a finite number of measurements. There were certain directions the polarization would more likely face in quantum mechanics. This test was more stringent. In mid-2007 Fedrizzi found that the new realism model was violated by 80 orders of magnitude; the group was even more assured that quantum mechanics was correct...

...Late last year Brukner and Kofler showed that it does not matter how many particles are around, or how large an object is, quantum mechanics always holds true. The reason we see our world as we do is because of what we use to observe it. The human body is a just barely adequate measuring device. Quantum mechanics does not always wash itself out, but to observe its effects for larger and larger objects we would need more and more accurate measurement devices. We just do not have the sensitivity to observe the quantum effects around us. In essence we do create the classical world we perceive, and as Brukner said, “There could be other classical worlds completely different from ours.”

Zeilinger and his group have only just begun to consider the grand implications of all their work for reality and our world. Like others in their field, they had focused on entanglement and decoherence to construct our future information technology, such as quantum computers, and not for understanding reality. But the group’s work on these kinds of applications pushed up against quantum mechanics’ foundations. To repeat a famous dictum, “All information is physical.” How we get information from our world depends on how it is encoded. Quantum mechanics encodes information, and how we obtain this through measurement is how we study and construct our world.

I asked Dr. Zeilinger about this as I was about to leave his office. “In the history of physics, we have learned that there are distinctions that we really should not make, such as between space and time… It could very well be that the distinction we make between information and reality is wrong. This is not saying that everything is just information. But it is saying that we need a new concept that encompasses or includes both.” Zeilinger smiled as he finished: “I throw this out as a challenge to our philosophy friends.”