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Owen Maroney worries that physicists have spent the better part of a century engaging in fraud.
Ever since they invented quantum theory in the early 1900s, explains Maroney, who is himself a physicist at the University of Oxford, UK, they have been talking about how strange it is — how it allows particles and atoms to move in many directions at once, for example, or to spin clockwise and anticlockwise simultaneously. But talk is not proof, says Maroney. “If we tell the public that quantum theory is weird, we better go out and test that's actually true,” he says. “Otherwise we're not doing science, we're just explaining some funny squiggles on a blackboard.”
It is this sentiment that has led Maroney and others to develop a new series of experiments to uncover the nature of the wavefunction — the mysterious entity that lies at the heart of quantum weirdness. On paper, the wavefunction is simply a mathematical object that physicists denote with the Greek letter psi (Ψ) — one of Maroney's funny squiggles — and use to describe a particle's quantum behaviour. Depending on the experiment, the wavefunction allows them to calculate the probability of observing an electron at any particular location, or the chances that its spin is oriented up or down. But the mathematics shed no light on what a wavefunction truly is. Is it a physical thing ? Or just a calculating tool for handling an observer's ignorance about the world ?
http://www.nature.com/news/quantum-physics-what-is-really-real-1.17585
(Score: 2) by boristhespider on Friday May 22 2015, @07:39PM
Pure pedantry, but GUTs combine the electroweak theory with the strong theory. A so-called Theory of Everything combines a (postulated) GUT with gravity. I'd note that we do not actually have a single, accepted GUT yet. The idea that the only force to lie outwith a unified theory is gravity is something of a fallacy, although it's certainly the only theory to lie outwith various extensions that are generally accepted as well-enough motivated.
(Score: 2) by hubie on Friday May 22 2015, @07:51PM
I am being careless between GUTs and ToEs (and whatever the hell other stupid acronyms that come next), but my intention was to talk of unified theories in general. All I'm saying is that it may turn out that you cannot combine all the forces into some nice compact model.
(Score: 3, Informative) by boristhespider on Friday May 22 2015, @08:01PM
Totally agreed. I've maintained for a number of years - from when I was an undergraduate all the way through a career in post-doctoral cosmology - that there is no a priori reason to assume that we can combine all four forces, particularly as only two of the four manifest themselves on macroscopic scales, and we are attempting to force all four into a formalism that was developed for electromagnetism, which unlike gravity actually acts like a force.
Frankly, since gravity doesn't behave like a force macroscopically, trying to shoehorn it into a theory developed for something that *does* behave like a force has always struck me as a bit odd. Yes, we can derive (linearised, classical) gravity by postulating a massless, spin-2 particle but I view that as little more than a mathematical curiosity. Hell, we can barely force together the strong force and the electroweak force, scuppered this time by the strength of the coupling of the strong force that pushes out of what is effectively just a Taylor series. Jumping the gun ridiculously by trying to shoehorn in something that may or may not provide a sane description of macroscopic gravity and which is even in vacuum nigh on impossible to renormalise isn't so much biting off more than we can chew as stuffing our gullets with styrofoam.
(Score: 2) by hubie on Friday May 22 2015, @08:56PM
But that is where the Nobels are!! :)
I never had to venture very far into cosmology, but that whole renormalization business always sounded unsettling to me (probably because I never sat down and did the math myself).
(Score: 2) by boristhespider on Friday May 22 2015, @09:20PM
About twelve years back in the university library I read through the three-volume "History of Quantum Field Theory", or whatever it was called, in lieu of revising for my exams. In these volumes no less than Schwinger commented something like, "I'm not sure that renormalisation is mathematically justifiable" (it is, arguably; but not the way it's normally presented), while Feynman was quoted as saying, to extraordinarily loosely paraphrase, "Physics is ultimately algorithms and there's no reason to assume that algorithms that work in one situation apply in another; there is therefore no reason to immediately assume we will ever find a theory of everything".
I'll be back in my old uni town next month. I'm tempted to try and blag my way into their library so I can track down those books again and find Feynman's quote in particular because it's influenced me very strongly. (The only other thing that's influenced me as strongly was Peebles, in a talk in Paris in 2004 or so, who pointed out that modern cosmology wants us to believe that 5% of the universe is made of the standard model(ish) - whose Lagrangian fits on a side of paper - while 25% and 70% respectively are meant to be two types of matter whose *entire physical description* are w=0 and w=-1. Peebles wasn't so much attacking dark matter and dark energy (although he was criticising the tendency to assume them), but commented "I don't like this description of dark matter in cosmology and *I introduced it*" (which is basically true). The point was more that while we might have phenomenological descriptions, there's no way that the *physics* of 75% of the universe is as simple as cosmology might say.