Showing posts with label Quantum Theory. Show all posts
Showing posts with label Quantum Theory. Show all posts

Friday, January 6, 2012

Has a Crack Appeared?

I came across an interesting and recent development in physics dating to 2009. The Scientific American reported on the matter on November 24, 2009 (link); New Scientist had an article on it dated August 9, 2010; that article is not online, but a summary of it is presented by The Daily Galaxy (March 24, 2011, link).

The discoverer in question is a physicist working at the University of California, Berkeley named Peter Horava or Petr Hoyava or, most likely, Petr Hoava. (That box stands for an r with a caron on top of it; the ASCII code is not recognized by Blogger.) Horava is also, according to Wikipedia, a member of the theory group at Lawrence Berkeley National Laboratory. Horava’s discovery, working with an allotrope (read “form of”) carbon known as graphene, is that the behavior of this carbon at near absolute zero temperatures suggests that Einstein’s spacetime may not be real at all, that gravity acts differently in different temperatures, that the warping of space and time by mass may be illusory. What we see is caused by gravitation which does not act uniformly everywhere. This view appears to confirm  the claims of quantum physics that gravity is due to an exchange of particles, like electromagnetism, in this case the graviton, not due to the deformation of spacetime.

Now this discovery is beginning to make waves for a reason. It promises, finally, a unified theory of gravitation which will make the results observed by general relativity and quantum physics agree with each other—but, to be sure, at some expense to General Relativity’s claim to universal applicability. Well.

And there is more. As might be expected, views of black holes, the big bang, dark matter, dark energy, and the expansion of the universe all appear in very different light. For this reason, rather than summarily dismissed, Horava’s suggestions and modified equations are getting a lot of attention from quantum physicists.

I note this here because spacetime is my favorite bête noire. Yet it is so fundamental to general relativity that any crack that separates those two words means a revolution in physics. Unfortunately I cannot hope personally to check the results however much I’d like to. It would require me to master Maxwell’s equations presented in his On Physical Lines of Force (link), the Lorenz transformations that “correct” or “complete” them, and—for that matter—the evolution of concepts as rendered in the language of mathematics all the way from the days of aether to the present. I haven’t got the right stuff. But I have a very keen intuition!

Friday, May 20, 2011

Fitting Equations

All that is clear about the quantum theory is that it contains an algorithm for computing the probabilities of experimental results. But it gives no physical account of individual quantum processes. Indeed, without the measuring instruments in which the predicted results appear, the equations of the quantum theory would be just pure mathematics that would have no physical meaning at all. And thus quantum theory merely gives us (generally statistical) knowledge of how our instruments will function. And from this we can make inferences that contribute to our knowledge, for example, of how to carry out various technical processes….

It follows from this that quantum mechanics can say little or nothing about reality itself. In philosophical terminology, it does not give what can be called an ontology for a quantum system. Ontology is concerned primarily with that which is and only secondarily with how we obtain our knowledge about this. [David Bohm and B.J. Hiley, The Undivided Universe, Routlege, 1993, p. 1-2]
David Bohm (1917-1992) was a quantum physicist. He wrote the definitive Quantum Theory (1951) that Einstein read and of which that sage said that it helped him, finally, to understand the theory. The book remains the central text in the field. The book from which I quote was Bohm’s last work, published posthumously, produced in collaboration with Hiley, a younger mathematician. It is subtitled An ontological interpretation of quantum theory. The book introduces an intuitively accessible (thus “physical”) version of quantum events in which new equations still produce the correct results but beneath them is another conceptualization of what really happens. Bohm approaches the perplexing particle-wave duality issue, for instance, by hypothesizing “that the electron is a particle with well-defined position and momentum that is, however, profoundly affected by a wave that always accompanies it. Far from being hidden, this particle is generally what is most directly manifested in observation.”

I bought this book soon after it appeared. I chanced across it, if that’s the word, while browsing in a bookstore near daughter Monique’s then new apartment; it fell into my hands. I read it, despite its forbidding difficulties (not written for the layman). It opened up huge vistas about the nature of science for me, and particularly the state of science in our times. The content of this book is quantum physics, but its thematic is the profound difference between knowing how we know (epistemology) and knowing what we know (ontology). So long as science is satisfied with fitting equations to observations—without a genuinely physical conceptualization of what actually is or happens behind the observations, science enters a stage of stagnation and of symbolical wizardry without genuine meaning. Bohm quotes a telling statement of fellow physicist, Murray Gell-Mann: “Quantum mechanics, that mysterious, confusing discipline, which none of us really understands but which we know how to use.”

My elated reaction to these revelations from a genuine insider then (and that’s now twenty years ago) was: “I knew something was wrong—but now I know why.” In a way, nothing derails as surely as huge success. And mathematical modeling of phenomena—without genuinely, intuitively, understanding them—has been exactly that. But in that process, in a way—having gained the power to predict and therefore to control—the deeper urge that actually feeds real science, the search for truth, is lost. I would, of course, extend this view backward to relativity (space-time?) and upward to astrophysics (singularity?).

Until I encountered this volume, I only knew of Bohm as one of the physicists—and no doubt often confused him with Niels Bohr, the Danish physicist, who forms the other polarity of quantum theory. Bohr was its high priest, its pope, and a dogmatic preacher of know-nothingism. He is quoted as saying: “There is no quantum world. There is only an abstract physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature...” [Emphasis in the original.]

Bohm own view of the problems related to relativity as well as quantum theory was that the answer lay beyond both; both were approximations that frayed at the edges. His own theory of an undivided universe, however well expressed in equations and however accurately matching observations, has not exactly caught on since 1993. But it’s early days yet. In a vast and contentious social process like science, where orthodoxy is very helpful in rising professionally, it takes a long time before paradigms fall.

An earlier work of Bohm’s, first published in 1980, titled Wholeness and the Implicate Order, provides a more accessible approach to his thought. Alas, I found that book long after I’d broken several teeth on his scientific summation.