Quantum Physics: Questions

[Surgenator]

I'm also over at the Physicsforums as "bahai" and I have gotten some great answers there about this topic. The duality of wave and particle of photons is likely a mistake (as seen in many youtube videos), because there is one theory that explains all of it. The duality is a mistake that is found in many text books because it is difficult explaining QM to laymen.

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The philosophical stuff you see about QM is all really just interpretation, interpretation that the actual physicists working on the math aren't interested in themselves.

Mistake? What is the reasonning behind that claim?

[logicalreason]

Here is what someone says:

The so called wave particle duality is a crock of the proverbial - see the FAQ:
http://www.physicsforums.com/showthread.php?t=511178

Here is a correct analysis of the double slit experiment:
http://arxiv.org/ftp/quant-ph/papers/0703/0703126.pdf

Its got nothing to do with acting like waves or particles.

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Quantum Mechanics is extremely difficult to understand. I don't think anyone really understands it yet. And the ones that do are probably doing math all day rather than writing articles or books.

[Surgenator]

Here is what someone says:

The so called wave particle duality is a crock of the proverbial - see the FAQ:
http://www.physicsforums.com/showthread.php?t=511178

Here is a correct analysis of the double slit experiment:
http://arxiv.org/ftp/quant-ph/papers/0703/0703126.pdf

Its got nothing to do with acting like waves or particles.

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Quantum Mechanics is extremely difficult to understand. I don't think anyone really understands it yet. And the ones that do are probably doing math all day rather than writing articles or books.

I believe you don't understand what physicist mean when they say wave-particle duality. It doesn't mean that sometimes it's one and not the other. It means objects have both wave and particle properties at the same time; they don't switch between the two. So when you setup an experiment to measure the wave-like properties, you get the wave-like properties. When you setup an experiment to measure particle-like properties, you get particle like properties. These properties are NOT mutally exclusive.

[logicalreason]

I didn't understand this at first, no. The sensationalist stuff in the media about the double slit experiment is essentially misleading.

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I think the water drop experiment is pretty close. a drop of oil on top of water, with two slit openings barriers, allows the oil drop to pass one slit, while the wave on the water passes both slits.

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Simultaneously.

[Surgenator]

I didn't understand this at first, no. The sensationalist stuff in the media about the double slit experiment is essentially misleading.

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I think the water drop experiment is pretty close. a drop of oil on top of water, with two slit openings barriers, allows the oil drop to pass one slit, while the wave on the water passes both slits.

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Simultaneously.

Is this the Millikan oil-drop experiment? This experiment showed that charge was quantized.

What did you think it showed?

[logicalreason]

No not the Millikan experiment. I am refering to this:

The experiments began a decade ago, when Yves Couder and colleagues at Paris Diderot University discovered that vibrating a silicon oil bath up and down at a particular frequency can induce a droplet to bounce along the surface. The droplet’s path, they found, was guided by the slanted contours of the liquid’s surface generated from the droplet’s own bounces — a mutual particle-wave interaction analogous to de Broglie’s pilot-wave concept.

http://www.wired.com/2014/06/the-new-quantum-reality/

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In a groundbreaking experiment, the Paris researchers used the droplet setup to demonstrate single- and double-slit interference. They discovered that when a droplet bounces toward a pair of openings in a damlike barrier, it passes through only one slit or the other, while the pilot wave passes through both. Repeated trials show that the overlapping wavefronts of the pilot wave steer the droplets to certain places and never to locations in between — an apparent replication of the interference pattern in the quantum double-slit experiment that Feynman described as “impossible … to explain in any classical way.” And just as measuring the trajectories of particles seems to “collapse” their simultaneous realities, disturbing the pilot wave in the bouncing-droplet experiment destroys the interference pattern.

Droplets can also seem to “tunnel” through barriers, orbit each other in stable “bound states,” and exhibit properties analogous to quantum spin and electromagnetic attraction. When confined to circular areas called corrals, they form concentric rings analogous to the standing waves generated by electrons in quantum corrals. They even annihilate with subsurface bubbles, an effect reminiscent of the mutual destruction of matter and antimatter particles.

[Surgenator]

I only recently heard of Pilot wave theory (literally 4 days ago). I read the article you linked, and pilot wave theory does seem to have extraordinary explanation powers. However, quantum mechanics did graduate to quantum field theory which describes multiple particle interactions and relativistic effects very neatly.

For pilot wave theory to become a scientific standard, it first need to produce new or better measurements. Second, it needs to incorporate particle creation and anniliation mechanics. Third, get special relativity in there.

So the physicist working on pilot wave theory still have a long way to go. I personally hope they succeed, but I'm not holding my breath.

[logicalreason]

Got it.

[Tobie]

QM needs observers, otherwise everything becomes Schrodinger's cat. Also, a lot of QM is based on what happens when you measure something - implying the need for a conscious observer.

[The Grand Nudger]

Consciousness isn't required for "observation" or "measurement" in the sense that they're talking about. One of the things that makes qm so difficult for me (and most laypeople - and most anyone) is the foreignness of it, and how it bends our use of language (and conceptualization). I suppose that's to be expected, QM is far removed from our experience, or our biological mechanisms with which to handle those experiences. Nothing "acts" like QM at the level we see, or hear, or feel, or taste. Talk about bringing a knife to a gun fight.