Physicists can’t solve nothing

From the opening section of a book on the many-body problem:
“It might be noted here, for the benefit of those interested in exact solutions, that there is an alternative formulation of the many-body problem, i.e., how many bodies are required before we have a problem? G. E. Brown points out that this can be answered by a look at history. In eighteenth-century Newtonian mechanics, the three body problem was considered insoluble. With the birth of general relativity around 1910 and quantum electrodynamics in 1930, the two- and one-body problems became insoluble. And within modern quantum field theory, the problem of zero bodies (vacuum) is insoluble. So, if we are out after exact solutions, no bodies at all is already too many!” (emphasis added)
In modern quantum, theoretical, and particle physics, physicists quite literally can’t solve nothing. This is not a double negative- “nothing” is already a problem with no exact solution, and anything more than nothing is even worse. Some progress.

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A Cosmic Computer?

In both popular and technical literature in subjects such as cosmology or theoretical physics, one can often find authors referring to the universe as a “computer”. I have found, however, that frequently non-specialists (including, sometimes, authors of popular literature) are misled by such characterizations. This is quite understandable. Inaccurate computer metaphors abound (particularly when it comes to the mind, brain, and consciousness), as do computers. Computer no longer brings up images of mechanistic calculations, and we no longer think of machines that carry out computations (like calculators) as “computers”, because “computers” are the laptops and desktops we are familiar with.

But when physicists call the universe a computer, they are asserting it has more akin with a pocket calculator than with your iMac or PC. Actually, in a very real sense by equating the universe with a computer physicists are saying it has more in common with your wristwatch or clock than your computer. Before the advent of quantum physics, it seemed as if the universe evolved deterministically according to some surprisingly simple dynamical laws (Newton’s equations of motion described just about everything, and what couldn’t be described by Newtonian mechanics could be by Maxwell’s equations, or Hamilton’s, or some other mechanics). The future state of any system is “computed” based upon current states entirely deterministically, like clockwork.

Quantum mechanics changed the deterministic part of this universe of computed states, but not the computation part. In quantum mechanics, the evolution of a system is still governed by entirely deterministic evolution (the famous Schrödinger equation, for example, is a linear partial differential equation, such that given any particular input we can compute, or the universe can, a single determined outcome). How indeterminism comes into the theory is not important here (especially because it is not exactly intuitive and involves going into the manner of preparation and specification of systems and measurements). What’s important is that even in quantum mechanics the future states of systems are given by dynamics so precise and “regular” they can be encapsulated by a few equations.

In the “universe as computer” concept, this encapsulation is really more of a description: the mathematical models are what the “universe” computes in order to evolve in time (i.e., to arrive at future states). This concept doesn’t entail a universe which is conscious, or that we are programs stored on some cosmic hard drive, that the universe has memory (at least no more than sandpiles or solitons), that we are living “in” a “computer”, or any other of the more exotic notions I’ve heard or read that result from comparing the universe to the things you use to check Facebook, create PowerPoint presentations, or visit this blog.

 

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Quantum Cognition: Physics Envy in Neuroscience and Psychology

I promise I won’t continue to do this, but I just want to ensure that the “millions and millions” of non-existent readers know that I have started another blog and that this one has a new central theme.

Research Reviews

The idea that quantum physics is not only relevant to consciousness or the “mind” is pretty widely known. After all, in addition to a plethora of popular books by authors with questionable expertise and/or knowledge, eminent physicists such as Sir Roger Penrose and Henry Stapp have supported this idea. This post isn’t about quantum theories of mind (which I don’t find persuasive). It’s about a large number of papers that begin by making this distinction, e.g., “We note that this article is not about the application of quantum physics to brain physiology.”; “In our approach “quantumness of mind” has no direct relation to the fact that the brain (as any physical body) is composed of quantum particles”; etc.

Simply put, the idea is that cognitive psychologists, neuroscientists, etc., should use the mathematical framework, notation, and terminology found in quantum physics (in particular, quantum mechanics) to model thinks like decisions, opinions…

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Photons aren’t real (but virtual photons are!)

Research Reviews

My concern here is mainly with the paper

Kastner, R. E. (2014). On Real and Virtual Photons in the Davies Theory of Time-Symmetric Quantum Electrodynamics. Electronic Journal of Theoretical Physics, 11(30).

I should say at the outset that the sensationalist title of this post is to compensate for a corresponding lack of sensationalism in the post, and should not be interpreted as a disparaging (or even negative) view of Kastner’s article. I may not be a proponent of transactional interpretations of quantum physics, but neither am I a detractor (and I certainly find it more plausible than multiverse-type interpretations). Before discussing photons and virtual photons, I need to briefly explain the “Possibilist Transactional Interpretation” (PTI). This is Kastner’s own version of the “Transactional Interpretation” (TI) put forward by Dr. John G. Cramer in the 80s. Luckily, this means that there already exists sufficiently simple and concise summaries of…

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English as a Second Language (ESL) for Ancient Greeks

I was looking into the extent of the unfortunate use of statistics from the social & behavioral sciences by particle physicists when I found this little gem in a footnote:

“Although the notion of what constitutes a satisfactory theory has changed over the centuries, it has always been considered desirable that the number of basic elements out of which everything is constructed should number at most “A FEW.” Since for the Greeks the basic elements were Air, Fire, Earth and Water, it is clear that they not only understood the basic principles of Science, but also had an excellent command of the English language.”
Lyons, L. (2008). Open statistical issues in particle physics. The Annals of Applied Statistics, 887-915.

Do I disagree with the claim that the Greeks understood the basic principles of Science? Sure (no empiricism, no science). Did I laugh like the biggest, most pathetic nerd in history upon reading this? Maybe.

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This blog is moving! And staying!

This blog was originally supposed to be about reviewing actual research, in particular the research behind news and similar media popular science reporting. And even though many posts here aren’t reviews, that’s nothing compared to the number of posts I’ve wanted to write about but didn’t because they weren’t reviews of research but rather comments, tutorials, notes, etc., on various academic comments. So I decided to create another blog for research reviews specifically (and intend to eventually transfer the posts made here that qualify as such to the new site), and change this on to reflect what it already partly is: a roadmap, guide, and resource to understanding academia (particularly the sciences) and to scholarship. The new blog site will be researchreviewsblog.wordpress.com.

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Request

I was asked to start a blog by several individuals and only decided to do so because I was constantly bombarded by questions or references (via email, phone, face-to-face, discussion boards, etc.) concerning articles in popular media about science research. I could finally start a blog that focused on something specific. Only, as soon as I started this thing, people finally stopped sending links to every online article or electronic version of some newspaper column or whatever they could find concerning physics, neuroscience, research methods, mathematics, biology, and other fields I’ve worked in. So all my would be sources for blog posts dried up, which explains the tiny number of blog posts given how long this blog has existed.

To the point: if any of the BILLIONS of followers I don’t have (and any of those I do) have questions regarding articles, documentaries, news, etc., on scientific research they are interested in, would like to know more about, are skeptical of, or even would like more references concerning, I would welcome such requests. Please.

Ask, and it shall be granted (sort of).

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