A physicist talks about woo-woo misuse of quantum mechanics

[Asympotically_fat]

@Skald_the_Rhymer

It’s been a while since I’ve done any reading on the subject, but it’s not my impression that the Cat is supposed to resolve anything; rather, it’s meant to point out a contradiction in QM. I agree it’s misinterpreted (both willfully & ignorantly) in pop culture.

It is correct, Schroedinger’s cat was a gedanken experiment proposed to sure the difference between the microscopic and the macroscopic world. However Schoredinger wasn’t aware of decoherence when he proposed his gedanken experiment and the conclusions that he drew from it aren’t the ones that a modern day physicist would draw from it. I.e. Schrodinger would say that this shows that quantum mechanics simply does not apply to the macroscopic world whereas a modern physicist would say that it illustartes decoherence and the futitly of trying to observe superpostion in macroscopic objects.

Now get me my healing crystals!

[Ludovic]

@Giraffe

Given that the thought experiment is typically given as |box> = a|decay> + b|no decay> = a|dead cat> + b|live cat>, my point was just that a big fat cat is a fundamentally different thing than a single radioactive atom in terms of its quantum description.

That’s just what the wall street fat cats WANT you to think.

[Giraffe]

@These are my own pants

Of course once decoherence has occured there still (by the postulates of quantum mechanics) exists superpostion. It’s just the system which is a superpostion of states (including states where the cat is dead and states where the cat is alive) is hell of a lot larger than the cat, so large in fact it includes the measurer and their equipment meaning that the old-style quantum measurement theory can’t cope with it.

I agree with everything you said, but would amplify that your language is not nearly strong enough. It’s not that the theory can’t cope (although of course it can’t), it’s that it would be nonsensical to even discuss the system in those terms. It would be like calculating the probability that your computer is going to fly off to the left based on every atom’s thermal motion happening to line up in the same direction. Basic statistical mechanics tells us that the probability of that is zero to more decimal places than we could write before we realized how futile it was and gave up in disgust.

I would argue that “technically possible” is a meaningless statement once the possibility of occuring within the lifetime of the universe nears zero.

[BlinkingDuck]

@shiftless

While we are on the subject of quantum mechanics, can we please kill the phrase “quantum leap.” It is commonly used to mean a huge change (see “sea change”) or a paradigm shift. Every time I hear it I think, “the smallest possible change? That doesn’t make sense.”

You’re looking at it wrong. I think they mean it is a ‘leap’ without crossing the space inbetween.

[Anne_Neville]

@Alka_Seltzer

Somewhat related, I felt the same when reading The Lost Symbol. I discovered I’m much happier with Dan Browne when he massacres religion instead of science.

“Thoughts have mass! Thoughts have mass!” “Weigh a soul!”

Is that why I’m overweight?

@Ludovic

That’s just what the wall street fat cats WANT you to think.

Schrodinger’s Wall Street fat cat?

[user_hostile]

@Superfluous_Parentheses

Quantum Mechanics confuses the hell out of me, but it really pisses me off when people who very obviously have even less understanding of it than me abuse it to promote their nonsense. Like the producers of the horrible “what the #&(#$ do we know” movies or much, much worse than that (and that’s saying something!): “Dr” Charlene Werner here, who doesn’t seem to have a grasp of even basic physics or math. Warning: this video will make your brain hurt.

Please note her credentials (bottom of the page):

“Dr. Charlene Werner is a homeopath and development optometrist who integrates homeopathy with light therapy and vision training to help improve the function of the body and to achieve well being and maximum visual function.”

I have no interest in her explanation of QED.

The philosophy she espouses can be expresses as “Science as Superstition”, or is it the other way around?

[Asympotically_fat]

@Giraffe

I agree with everything you said, but would amplify that your language is not nearly strong enough. It’s not that the theory can’t cope (although of course it can’t), it’s that it would be nonsensical to even discuss the system in those terms. It would be like calculating the probability that your computer is going to fly off to the left based on every atom’s thermal motion happening to line up in the same direction. Basic statistical mechanics tells us that the probability of that is zero to more decimal places than we could write before we realized how futile it was and gave up in disgust.

I would argue that “technically possible” is a meaningless statement once the possibility of occuring within the lifetime of the universe nears zero.

I also agree with what your say. Infact the actual probabilty of observing superpostion phenomena in a cat is insanely small. So small infact I’d guess you’d have use some sort of variant on Knuth’s up arrows to represent it.

But I’m not being pedantic,it’s always still worth remembering that by the psotulates of quantum mechanics that when describing decoherence there still is superpostion. The ‘cat system’ is not evolving unitarily so it’s wrong to describe this subsystem in terms of a wavefunction, but the cat system is pat of some larger system that is evolving unitarily. The non-unitary evolution of the cat is a result of the unitary evolution of the larger system and that shoudln’t be ignored as decoherence is derived from assuming that we can describe the larger system (of course when I say larger system I could very well mean the whole universe) in this way.

[Ludovic]

@Anne_Neville

Schrodinger’s Wall Street fat cat?

There were a lot of those during the tech bubble. Simultaneously millionaires and paupers.