tag:blogger.com,1999:blog-8148573551417578681.post3881436562281911825..comments2021-01-15T10:36:20.149-08:00Comments on Dark Buzz: Greene video pushes action-at-a-distanceRogerhttp://www.blogger.com/profile/03474078324293158376noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-8148573551417578681.post-50730658415710652132020-05-07T23:39:03.859-07:002020-05-07T23:39:03.859-07:00Dear Roger,
0. Somewhat unrelated, but let me not...Dear Roger,<br /><br />0. Somewhat unrelated, but let me note it anyway.<br /><br /><br />1. A few weeks ago, we discussed IAD (instantaneous action a distance) following your post: https://blog.darkbuzz.com/2020/03/trying-to-prove-many-worlds-from-first.html .<br /><br />In a comment to that post, you had pointed out: <br /><br />"...if you can suddenly change V everywhere, then you can have instantaneous action-at-a-distance. Relativity and quantum field theory are designed to explain how a field can get from one place to another."<br /><br />Now, here are my thoughts (which I didn't mention at that time).<br /><br />1. In the context of QM, the established position is that \Psi is a function of *all* potentials, not just the electrostatic ones. Thus, \Psi is a function of the magnetic field too, if one is present. (Ditto for gravitational and any other fields.) <br /><br />Now, EM fields don't show IAD; disturbances propagate locally as EM pulse-profiles i.e. waves. Therefore, changes in \Psi, too, cannot propagate instantaneously.<br /><br />I have little trouble accepting it all. <br /><br />2. However, I was also just wondering [and this is the "somewhat unrelated" part], what happens if we regard the magnetic field as an *effect* of quantum-mechanical processes, the latter being regarded as more basic? <br /><br />I mean to say, suppose that the \Psi field does change instantaneously, because the electrostatic field (the "V" in the Schrodinger equation) itself also changes instantaneously. Suppose further that the magnetic field only is an emergent field; it is just another name for some aspects (notably spin-related aspects) of how the combined \Psi corresponding to a *large* number of elementary particles changes with space and time. Suppose that the *emergent* field (which we call magnetism) does show locality (the Maxwellian waves). <br /><br />In such a case, the EM field turns out to be local, but only at a higher level of abstraction. At a more basic level, everything is governed by just "electrostatic" (inverse-square) V field between charges, and the non-relativistic Schrodinger equation. So, all changes occur instantaneously everywhere. <br /><br />*In short, what if we regard the magnetic field as a quantum mechanical effect of elementary charges, rather than as a relativistic effect (as Feynman explains in his text-book) of gross bodies?*<br /><br />3. The above idea isn't as arbitrary as it might seem on the face of it.<br /><br />Realize, all EM phenomena have been established only in reference to gross bodies, containing a very large number of elementary particles (10^23, to indicate the order). Special relativity is a consequence of Maxwell's equations. If magnetism lies at a higher level to QM, then so does EM. And, therefore, so does relativity. And, therefore, the ideas of locality inspired in the fold of any relativistic theory have no relevance at all at the QM level, because QM now is *twice* basic to relativity: Rel -> Electrodynamics -> QM -> "Electrostatics" i.e inverse-square potential (changing instantaneously, but only between elementary particles) <br /><br />Just a thought. <br /><br />But one thing is for certain. Relativity has been validated only in those situations where both multi-scaling effects (from sub-nano-meter scale to meter-scale) and large ensembles (Avogadro) are absolutely relevant ideas. On the other hand, in principle, QM applies to even just two elementary particles separated by a very small distance (small fractions of angstrom or 0.1 nm). So, there.<br /><br />Best,<br />--Ajit<br />Ajit R. Jadhavhttps://ajitjadhav.wordpress.comnoreply@blogger.com