Skip to main content

A paradox turns out not to be real. Whew.




Quantum mechanics seems a little bit less weird and counter-intuitive now than it did before November. Since around last Thanksgiving a scientific paper has been making the rounds, and gradually it has become grist for science journalists

Now the idea has come to you, via my humble blog. The Cheshire cat and its smile do not actually separate in the quantum world. 

It has long been thought that certain subatomic particles can be in one place and that certain of their properties can be in another. Ah, what a mystical idea! what a contribution to the reputation of quantum mechanics for sheer weirdness!  Indeed, no less a physicist than Albert Einstein objected to the "spooky stuff" in quantum mechanics in its early development. 

Einstein wasn't wrong. There is spooky stuff and it does make quantum physics look like something less-than-ultimate, something that will be explained by something else deeper as thought progresses. If Einstein turns out to be right about that, though, the process of demystification may take a while yet. 

And here there is a provisional victory for Einstein's skepticism. Cats do not zig while their smiles zag. Likewise subatomic particles do not zig when their properties (spin or polarization) zag.  The polarization is merely a fact about the particle and, so far as we know, the polarization is wherever the particle is. Here is the peer-reviewed paper, in THE NEW JOURNAL OF PHYSICS, that explains why the results of experiments on the subject, previously cited as evidence of the Cheshire car effect, do not really make any such thing evident.

 https://iopscience.iop.org/article/10.1088/1367-2630/ad0bd4  

And, okay, the prose there is a little dense.  If you want a more straightforward explanation, Sabine Hossenfelder offers one here: 

  https://backreaction.blogspot.com/2024/01/another-famous-quantum-mystery-was-just.html  

My sense of irony is piqued by the fact that the scientists involved in debunking the Cheshire cat paradox appear to work out of Hiroshima University, in Japan. No doubt a place where there are firm opinions about subatomic physics, and about who ought to win the next Academy Award for Best Picture. 

"I am become death for a Cheshire cat," said no physicist ever.   

Labels:

Comments

Post a Comment

Popular posts from this blog

A Story About Coleridge

This is a quote from a memoir by Dorothy Wordsworth, reflecting on a trip she took with two famous poets, her brother, William Wordsworth, and their similarly gifted companion, Samuel Taylor Coleridge.   We sat upon a bench, placed for the sake of one of these views, whence we looked down upon the waterfall, and over the open country ... A lady and gentleman, more expeditious tourists than ourselves, came to the spot; they left us at the seat, and we found them again at another station above the Falls. Coleridge, who is always good-natured enough to enter into conversation with anybody whom he meets in his way, began to talk with the gentleman, who observed that it was a majestic waterfall. Coleridge was delighted with the accuracy of the epithet, particularly as he had been settling in his own mind the precise meaning of the words grand, majestic, sublime, etc., and had discussed the subject with William at some length the day before. “Yes, sir,” says Coleridge, “it is a majesti
7 comments
Read more

Five Lessons from the Allegory of the Cave

  Please correct me if there are others. But it seems to be there are five lessons the reader is meant to draw from the story about the cave.   First, Plato  is working to devalue what we would call empiricism. He is saying that keeping track of the shadows on the cave wall, trying to make sense of what you see there, will NOT get you to wisdom. Second, Plato is contending that reality comes in levels. The shadows on the wall are illusions. The solid objects being passed around behind my back are more real than their shadows are. BUT … the world outside the the cave is more real than that — and the sun by which that world is illuminated is the top of the hierarchy. So there isn’t a binary choice of real/unreal. There are levels. Third, he equates realness with knowability.  I  only have opinions about the shadows. Could I turn around, I could have at least the glimmerings of knowledge. Could I get outside the cave, I would really Know. Fourth, the parable assigns a task to philosophers
Post a Comment
Read more

Searle: The Chinese Room

John Searle has become the object of accusations of improper conduct. These accusations even have some people in the world of academic philosophy saying that instructors in that world should try to avoid teaching Searle's views. That is an odd contention, and has given rise to heated exchanges in certain corners of the blogosphere.  At Leiter Reports, I encountered a comment from someone describing himself as "grad student drop out." GSDO said: " This is a side question (and not at all an attempt to answer the question BL posed): How important is John Searle's work? Are people still working on speech act theory or is that just another dead end in the history of 20th century philosophy? My impression is that his reputation is somewhat inflated from all of his speaking engagements and NYRoB reviews. The Chinese room argument is a classic, but is there much more to his work than that?" I took it upon myself to answer that on LR. But here I'll tak
13 comments
Read more