Science educator Sabine Hossenfelder is a research fellow at the Frankfurt Institute for Advanced Studies. But Hossenfelder's latest YouTube video expounds upon the sorry state of particle physics, and in the process also has some interesting sidenotes on dark matter.She talks a lot of about models that expand the symmetry to some larger, possibly broken, symmetry. For example the grand unified theories combine the weak and strong interactions into a larger group. Supersymmetry also adds many symmetries, and so does string theory.

Hossenfelder criticises what has become the standard operating procedure of particle physicists, whereby they routinely predict the existence of particles that violate the Standard Model. Eventually, the postulated particles are experimentally falsified, at which time physicists move on to even more fanciful predictions.

Hossenfelder is pessimistic about the future of the field if particle physicists continue to behave in the same manner going forward. Hossenfelder also notes that in the past 50 years, only a handful of predictions have been validated, and all these were necessary elements of the Standard Model.

There is an argument for such theories that goes like this. The history of Physics is in finding broader theories that unify others. Newton's gravity unified terrestial and celestial gravitation. Maxwell's theory unified electricity and magnetism. They were truly unified in that a moving electric field would generate a magnetic field, and vice.

So it seems conceptually desirable to unify strong and weak forces, with a larger symmetry group.

But it is not. All these theories cause drastic increases in complexity, and in unknown parameters needed to define the theory. Having more symmetries does not reduce the complexity because the symmetries are broken.

With electromagnetism, the symmetry is real, and you can do away with magnetism, and treat it as a relativistic effect of electricity. With the grand unified theories, there is no advantage to the extra symmetry at all. It does not make the theory more elegant.

All of this would be irrelevant if there were experimental evidence for the unified theories. As Hossenfelder explains, many billions of dollars have been spent looking, and none found.

Roger,

ReplyDeletePeople often have a problem admitting they are lost, because this immediately leads to an even bigger more distressing problem: 'When exactly did they become lost...just how far are they going to have to back up the damn car until they are back on track.'

Sabine Hossenfelder is admirable in that she admits particle physics is lost and growing ever more deluded by the next paper published. My only concern with her assessment is that I don't think she wants to admit how lost it actually is. Sabine is backing up the car to about 1970 and stating it went off the tracks from there. I believe the problem actually goes back far further, which is disheartening to anyone (like Sabine) who has made it their life's work to study the intricacies of their chosen discipline. In order to make a large correction, much of what they profess to know will have to be discarded and then they will have to weather the slings and arrows of esteem withering questions and scrutiny about how they could have been mislead for so long...after all, they are the vaunted experts.

The strong and weak nuclear forces are a byproduct of a very flawed model of how atoms stucturally work. Instead of creating a multiple of magical heuristical constants or forces to solve problems based on matching only the periodic outcomes (like epicycles can be used to predict orbits), once the subject matter at hand (atoms) are more carefully observed , the heuristics become entirely untenable (just as you notice by direct observation that celestial orbits are not even remotely perfect circles). Atoms have many moving parts in their structures, they do move you know, and I'm NOT talking about electrons whizzing about in Rutherford orbits around static spherical globs of neutron and proton monkeybread.

Current atomic theory is much like epicycles in that the ideas were formulated at a time of very little observation being even remotely possible. Outcomes were easier to observe than inner processes. Atoms are not black box mathematical algorithms however, just as orbits aren't perfect mystical platonic geometric circles within periodic circles. If you want the atomic model and what follows from it to work, The math has to follow structure by modeling it correctly, not the other way around.

My strong suggestion for particle physics is: Take another long look at atomic structure, and for griefs sake, Learn what your god damn charge actually is about. Charge is the actual 'god damn' particle of nature, not some symmetry breaking math fudge called a Higgs. Charge isn't unassigned math or Benjamin's abstract plus and minus symbols floating about in your platonic math reality. Charge is where it all starts, it's what makes everything go, and determines how it moves...and it also so happens to be the basis of the entire electromagnetic field. Start at the beginning and leave all the ever useless black hole/multiverse humping happy horseshit paper publishing to the cheesy star trek screen writers.