In my semi-retirement — as a physicist-turned-futurist — I have a couple of options to pursue in terms of fundamental projects. As a futurist, the most natural fundamental project — here in The Anthropocene — is to try to work out how to help save the world (for the most recent of my efforts so far, see the four NATO posts). As a physicist, the most natural fundamental project is to try to understand the foundations of quantum mechanics. I leave it as an exercise for the reader which of those has the greater chance of success … 😁
- Part I – ‘The Coyote Problem’
- Despite a century of unprecedented empirical success, the interpretation of quantum mechanics still remains very contested. In general, it seems undertaking any attempt to try to actually make sense of it is “considered barely respectable at all, if not actively disparaged” (Carroll 2019, p.4). Multiple interpretations coexist—Copenhagen, Bohmian, Many Worlds, Objective Collapse, Quantum Bayesian and so forth, at least a dozen or so—each with committed proponents and unresolved difficulties. No consensus view has emerged. Quantum theory has taken on an almost mystical reputation, much of which is, frankly, arrant nonsense (Bricmont 2017).
- Part II – Coming Back Down Towards the ‘Ground’
- The main contention of the previous post can be summed up as: the Schrödinger equation is to quantum mechanics what the Hamilton-Jacobi equation is to classical mechanics. This meant that we therefore found ourselves three levels of abstraction away from, and ‘floating’ above (so to speak), the ‘ground’ that classical mechanics was founded upon, namely Newtonian mechanics in 3D space. This post now begins the process of thinking about how to come down again to seek a more solid footing, if indeed there even is one to find…
- Part III – An Option for the ‘Ground’ State
- In previous posts we have encountered the three main equivalent re-formulations of classical (i.e., Newtonian) mechanics—Lagrangian, Hamiltonian, and Hamilton-Jacobi—as well as their quantum mechanical counterparts, Feynman path integrals, Heisenberg’s operator mechanics, and Schrödinger’s wave mechanics, respectively. We are now ready to think about what the final step ‘down’ might be to the quantum side of the bottom level of the ladder of abstraction, the quantum equivalent of the ‘ground’ from which classical mechanics arose.
- Part IV – For Whom the Bell (Theorem) Tolls
- Bell’s Theorem excludes a certain class of theories from being viable, and experiments have shown it to be correct, so we’d better pay attention to what the Universe says about its own behaviour. No matter how beautiful you think your theory is, nor how much you love it, it’s always the Universe that gets the final say.
- Part V – ‘The Duckmole Problem’
- Quantum theory has been plagued since its formulation by a conception known as “wave-particle duality”, a throwback to two distinct and incommensurable concepts from classical physics, forced together into an uneasy shotgun marriage. It was natural for the founders of quantum theory to try to understand and make sense of the new physics in terms of what they were familiar with. But 100 years later, perhaps we can dispense with such unhelpful constructs and seek to develop a nomenclature that moves beyond such dualities and treats quantum entities on their own terms. This may help dispel some of the contortions necessary to accommodate concepts that are not only outmoded but counterproductive. Luckily, some progress has been made on this front.
- Part VI – The Coyote Has (Almost) Landed – ‘The Fenchurch Problem’
- Here we will examine and interpret in detail the Level 1 primitive ontology and epistemological stance of the de Broglie-Bohm theory. We might disagree a bit with the conventional view…
- Part VII – The Classical Lagrangian Basis of Quantum Mechanics
- Some explorations of the classical mechanics Lagrangian basis for quantum theory, as preparation for the next post.
- Part VIII – The Transition |M⟩ → |Q⟩
- The transition from (classical) Mechanics to Quantics.
- Part IX – To Infinity and Beyond (Timelike, Spacelike, Null)
- Then comes the question of how this all fits in with relativity…
- Part X – Epilogue: The Sum of the Histories of This Exploration
- Some reflections on this process.
$\strut^*$Note on the title of the series. When I started to do this investigation around three years ago (mid 2023), this title was what I was imagined the process would be; looking at how quantum mechanics was developed, seeing what it says about the world, and trying to figure out a way to dig ‘beneath’ the multiple competing interpretations of it, in order to come to my own view of what might be the interpretations worth taking seriously. It was always a case of “reverse-engineering” the theory in my mind. Now, on re-reading Carroll’s (2019) book, I find that he mentions reverse-engineering at least three times (pp. 268, 282 & 284). It came as something of a surprise to me to see those precise words there. I don’t think I got the title idea from Carroll, since I am pretty sure I bought his book after the project had begun. On the other hand, the idea of “reverse engineering” something to try to see how it works is also a pretty common metaphor, so maybe we just had the same quantum-entangled thought about a topic that is of interest to both of us. At least, that’s how I think I prefer to explain this “spooky idea resonance at a distance…” 😁
Carroll, Sean M. 2019. Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime. Dutton / Penguin Random House.