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, thou...
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I saw an odd question on Quora recently. I suspect it was asked by someone with a weak command of English language idioms, and I answered it accordingly. But it leads to thought about a fascinating incident in the history of physics, the Bohr-Einstein correspondence over quantum physics. The question was as follows: What's the meaning of "only to have Bohr" here? "Einstein would come up with a scenario in an attempt to defeat the quantum theory, only to have Bohr present an argument consistent with quantum theory that overcame it"? I answered as follows. If the idiom is unfamiliar to you, it is because of the conditional wording of the sentence. “A would do X, only to have B do Y.” One could rework it this way, “Einstein repeatedly came up with scenarios in an attempt to defeat the quantum theory, and in each case Bohr presented an argument consistent with quantum theory that overcame it.” It was Bohr, by the way, who got the publication cre...
"Cautiously one can say this: The attempt to understand the quantum theoretical description of the individual systems leads to unnatural theoretical interpretations, which immediately become unnecessary if one accepts the view that the description refers to the system as a whole and not to the individual system. The w hole approach to avoid 'physical-real' becomes superfluous. However, there is a simple physiological reason why this obvious interpretation is avoided. If statistical quantum theory does not pretend to describe completely the individual system (and its temporal sequence), then it seems inevitable to look elsewhere for a complete description of the individual system. It would be clear from the start that the elements of such a description within the conceptual scheme of the statistical quantum theory would not be included. With this, one would admit that in principle this scheme can not serve as the basis of theoretical physics.” A. Einstein, Out of my ...
One can read much of the book free, through the Google Books platform. I was curious what if anything Ball would have to say about Quantum Bayesianism (QB), which I have mentioned in this blog a time or two. The answer is that he treats it as one interpretation of quantum mechanics among many, alongside Copenhagen, many worlds, collapse models and pilot waves. QBism is, he sees, the culmination of the Copenhagen view. "Quantum mechanics generally assumes that quantum states exist in some meaningful sense, and that the math tells us what we can know about these states. But in QBism there are no objective states. Rather, according to Chris Fuchs, 'quantum states represent observers' personal information, expectation and degrees of belief'. " Bohr had said (outlining what is now called the Copenhagen view) that (in Ball's paraphrase), "the purpose of quantum mechanics is not to tell us about reality but to predict outcomes of measurements." ...
There has been a fair amount of speculation about how the phenomenon of quantum entanglement could produce faster-than-light communication. This means, within the context of the physics of relativity, that a message recipient an appropriate distance away (say, on earth's moon base) could learn of events on earth before they happen. One common example of quantum entanglement involves socks. A physicist named Reinhold Bertlmann (who retired in 2010) was notorious among his colleagues at the University of Vienna for always wearing different colored socks. So if you observed only his left ankle, you could say something with certainty about the sock on the right ankle. If the left sock was pink, the right sock was NOT pink. In 1981, J.S. Bell actually wrote an article for a serious peer-reviewed journal of physics with that phenomenon in the title, "Bertlmann's Socks and the Nature of Reality." If we imagine that the pair of socks becomes separated, and the right ...
I included a comic in yesterday's post -- one which mentioned the Buddha is a hypothetical sort of way Today, we will invoke an actual carton image OF said Buddha. This is funny and thought provoking. If the recipient is pleased with the box, then the gift is the box, not the absent coffee maker. Had the Buddha been confused or unhappy about the empty box, the giver would have apologized and run off to fetch the coffee maker. A superposition of possibilities here. Would this be like Schrodinger's cat? Let's not try to press that thought too hard....
Yes, I understand that introducing "quantum theory" into a discussion of the foundations of morals is over-done. It has become associated with New Age fishiness. I will go there, regardless. Suppose a certain swindler has stolen money that properly belonged to a worthy charity, and “Made Off” with it. His theft might have rendered the charity helpless to do some good works on which helpless beneficiaries of its attentions had come to rely. This event must be for us (if we are deterministic) something more than a one-time bad event or evil action. It must be a baked-in feature of the universe. The laws of nature demanded mercilessly and without recourse that the swindler had to swindle, the charity had to be rendered impotent, the helpless had to suffer. Without any other ‘could have been’ this tragedy before a part of an irremediable tearfulness of things. If, imbued with healthy animal spirits we seek to escape that pessimism about the whole of t...
I simply want this to be expounded once in this blog. I've alluded to the double slit experiment in some of my recent remarks on quantum theory and its philosophical overlay, and I even pasted an image of one hypothetical result of the experiment onto my most recent such discussion. But for this once I'll be explicit. Imagine that electrons, or photons, are little tiny particles, as Democritus might have imagined. Imagine shooting them (in Chicago-movie machine-gun fashion) at a wall that had two parallel slits in it, and that there is a screen behind the wall, such that each particle that gets through the slit leaves a mark on the screen. What would you expect to see on the other side of that wall? You'd likely expect to see marks directly behind each slit, corresponding top the shape and size of the split. Some portion of the screen that lay between the two slits would presumably be left unmarked. That's not what happens. Consider light first. Thomas Young d...
Why do ordinary folks like me, who know nothing about advanced physics and only a smidgen of calculus, ever write about quantum mechanics? Heck, why do people who DO know the physics and all the necessary math, people like Fritjof Capra or Lee Smolin, persist in targeting writings on the subject to folks like me? The journalist Gary Zukav wrote The Dancing Wu Li Masters in 1979. This work has been much ridiculed as "New Age" stuff pretending to be physics. But Zukav wrote it after talking to a lot of real working physicists, participating in a 1976 physics conference as Esalen Institute, California, etc. Physicists don't just "talk among themselves" on these points. They make efforts to talk to the rest of us, explaining what it means. So they have to expect t...