tag:blogger.com,1999:blog-5376628436133716219.post2272431733048220015..comments2024-03-29T02:14:39.189-07:00Comments on Why I hate physics: The Quantization of Spin RevisitedMarty Greenhttp://www.blogger.com/profile/17624084719249673373noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-5376628436133716219.post-80101451074785759582017-02-09T08:11:44.672-08:002017-02-09T08:11:44.672-08:00Yes, Frederic, you've identified my error. The...Yes, Frederic, you've identified my error. The donut (ring) is what you get from a pure quadrupole field, but I assumed the addition of the DC field would have no effect. In fact, it causes a precession which disrupts the side-to-side effect, leaving only the up-and-down polarization.Marty Greenhttps://www.blogger.com/profile/17624084719249673373noreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-54675522079865236182016-10-07T04:56:19.269-07:002016-10-07T04:56:19.269-07:00In the Stern—Gerlach experiment, it’s not a pure q...In the Stern—Gerlach experiment, it’s not a pure quadrupole, but at least the sum of a quadrupole and a constant field. If one treats the magnetic moment classically, the constant field induces a Larmor precession, so that the movement orthogonal to the field average out to 0. This leads to a vertical line and not a ring for unpolarized classical magnetic moments.<br /><br /> A complete quantum treatment uses spinors and wave-packet, and I haven’t done it. A simpler approximation, neglecting the quantum effects on the position (small λ de Broglie) consist in using the direction of the magnetic field as quantization axis. This leads to two points for a narrow beam.<br /><br />Without an added global constant field, as in a pure quadrupolar field, I agree that it would lead to a ring for an unpolarized beam, but it is not the situation in the Stern–Gerlach experiment. Furthermore, if you send a fan beam to such a field, you will have the addition of many rings, not an elongated one, and this will remove the central hole. I do not see how a mixture of rings would explain the experimentally observed eye pattern.<br />Frédéric Grosshanshttps://www.blogger.com/profile/03874793734031585379noreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-82406403029299296532015-08-28T05:14:22.387-07:002015-08-28T05:14:22.387-07:00That's brilliant. The slide shows a modified v...That's brilliant. The slide shows a modified version of the elliptical tracde found in the actual Stern-Gerlach results, which they got by using a fan-shaped beam (from a slit aperture), not a pencil beam. But the text does not acknowledge this at all. It blithely continues as though the pencil-shaped beam had been split into two dots at the screen.Marty Greenhttps://www.blogger.com/profile/17624084719249673373noreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-9387381885793164962015-08-28T01:28:22.480-07:002015-08-28T01:28:22.480-07:00Hi, check out the first slide here, you may like i...Hi, check out the first slide here, you may like it:<br />http://www-bcf.usc.edu/~tbrun/Course/lecture02.pdf<br /><br />Look at:<br />- the pattern on the screen,<br />- the legend below the figure.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-66900545700776681352015-03-28T14:35:08.997-07:002015-03-28T14:35:08.997-07:00Glad you like it, Mark. Have you read my posts on ...Glad you like it, Mark. Have you read my posts on quantum siphoning?<br /><br />http://marty-green.blogspot.ca/2014/12/wave-function-collapse-explained-by.htmlMarty Greenhttps://www.blogger.com/profile/17624084719249673373noreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-52738016101945165682015-03-28T06:08:28.016-07:002015-03-28T06:08:28.016-07:00Very interesting, thanks.
Have you refined your id...Very interesting, thanks.<br />Have you refined your ideas since writing this blog?Markhttps://www.blogger.com/profile/02244810658101137268noreply@blogger.com