How to Start (or Restart) Learning Quantum Physics

If you’re a non-scientist like me, then learning good science can be difficult. One of the trickier arenas is quantum mechanics. I hope this post gives you a few ideas about where to learn or review the main ideas. 🙂

How to Start Learning Quantum Physics

I just returned from a crash course in quantum mechanics for science fiction authors at the Joint Quantum Institute’s (JQI) second annual ‘Schroedinger Sessions 2’ workshop, at their famed labs at the University of Maryland. What an amazing mind-treat it was! If they do the event again, and you’re a science fiction writer, then you should apply. (link: http://jqi.umd.edu/Schrodinger-sessions-II )

It was kind of like an in-depth graduate seminar introduction to the field, with engaging presentations from many noted experts. Among them we heard from Chad Orzel, Steve Ralston, Shelby Kimmel and her work with quantum algorithms for quantum computing,  and Bill Philips (nobel laureate), and a nice surprise visit from Peter Shawhan on his involvement with the LIGO project on the new astronomy of gravitational waves. Many thanks to JQI, to Dr. Emily Edwards, and everyone for the chance to engage such a strong level of learning.

Author Ed Lerner wrote up some of his experience over at his blog (link). “Schroedinger’s frog goes… ” Quoting him:

QM is a hot field in which phenomenal progress has been (and continues to be) made. Among my favorite topics at the sessions was quantum computing — something which, back in my university days, neither the physics nor the computer-science curriculum envisioned. Other sessions delved into:

  • atomic clocks,
  • superconductors and superfluids,
  • the nature of the quantum vacuum,
  • counter-intuitive features of quantum physics (that’s pretty much all of them) (*),
  • competing interpretations of what the mathematical formalism of QM means physically, and
  • much, much more.

(*) Including, of course, the puzzle/paradox/conundrum that is Schrödinger’s cat.

And the course also included some debunking, such as why human teleportation (such as transporters in Star Trek) just won’t work (well, at least not without a 200lb vat of biomolecules at both ends of the transporter). (Rats!)

But everday butterfly wings (in this case a dark variant female tiger swallowtail in my yard) do have all sorts of interesting optical effects, including quantum optics related to superconductors (http://phys.org/news/2008-09-butterfly-wings-scientists-photonic-crystals.html)

TigerSwallowtail-darkvariant02016schecklerWEB

Where to begin: the history of ideas

… a good way to enter an understanding is to look at some history of ideas. Quantum mechanics comes from some basic, fascinating questions such as What is light? How does it work?

And herein is one of the biggest realizations, that contrary to prior thinking that light was only a wave, or only a particle, it is better understood as being something that exhibits the behavior of both waves and particles, based not on absolutes, but rather, on ranges of probabilities and interference patterns. The more I think about this, the more astonishing it really seems.

For a much better series of explanations and ideas than what I can write here, I suggest trying these books:

Chad Orzel How to Teach (Quantum) Physics to Your Dog

Another great book on history, as a route into understanding quantum mechanics, is Uncertainty, by David Lindley, and Louis Gilder’s The Age of Entanglement, which is very well-written and accessible.

What does it mean to make a measurement?

We are all experimental physicists taking and testing measures of our world, often through simple trial and error. To make a measurement we must compare and contrast one range of observable things with another — a ruler with the world. But when what we measure is extremely small, the ruler can affect what we’re measuring. That’s a big problem within the extremely tiny world of subatomic events. Measurement can be arbitrary and it’s hard to know what is the observer and what is the system being observed. In this sense, all quantum systems are continually being observed and measured through their interaction with the environment, which in quantum physics language is to say that “entanglement is continually destroyed.” Measurements collapse the system’s probabilities. An amazing scifi thriller novel on this topic is Ted Kosmatka’s The Flicker Men

Some other books related to these issues:

The Great Wave, D. Hackett Fisher. This is more of a history of measuring related to economics, but it’s great

The Measure of Reality, A. Crosby This book details changing ideas of measurement from a historical view.

Isn’t Measurement a Type of Information?

Absolutely, yes. Information Theory sits at the foundation of modern computing. It suggested that information was different than the medium that the information relies on. In the age of mechanical computing (like the abacus or gear-driven calculators, information is closely connected with the equipment). But today we see it can be separate, so you could write a software program that could be run on many different computers. This means we might put a lot of information into many tiny things… that handy USB thumb-drive with solid memory circuits is a quantum device. And speaking of measurement, it’s lovely to consider how vast the very small really is. On the topic of nanotechnologies and the tiny, you might enjoy taking a look at Richard Feynman’s 1959 talk ‘Plenty of Room at the Bottom’ (link: http://www.its.caltech.edu/~feynman/plenty.html )

How do quantum relationships alter our older understandings of types of energy?

How does quantum mechanics relate to kinetic energy of movement such as waves, oscillations, radiant sources, electrical energy, thermal, sound… and potential energy such as chemical, stored mechanicals like springs, nuclear, and gravitation)? The answer is ‘it alters all of these.’ So that then makes me wonder how do quantum relationships affect our understandings of basics such as the Law of Conservation, and energy efficiencies, and how atoms work? Again, the basic response is ‘all ways.’

I’m just old enough that a lot of what I learned about atoms and molecules when I was a kid in grade school and high school science classes is outdated information. I grew up with the Bohr model of the atom, of electrons flying around nuclei like a tiny solar system, moving up and down orbits depending on the electron’s excitement. This suite of ideas has changed a lot, and is now better understood not exactly as orbits but as fields of probable locations for a negative charge that can be called an electron, tiny packets of waves and wavy-particles. I do feel like cloudy, chancy, fuzzy ways of detailing what we know about the world is a better match for our day-to-day experiences.

And what does quantum mechanics explain differently, and better than classical mechanics?

What does this tell us about the world? One short response here is that where classical mechanics tended to emphasize a culture-driven sensibility of unchanging ideals of an eternal completeness and perfection, new quantum mechanics contested these outdated ways of thinking.  Quantum Mechanics details incompleteness, probability, indeterminacy and the dynamic (or changing) ways of the world. In a way, quantum mechanics is able to take accident and randomness into account. Compared to classical mechanics the quantum methods are messier, but since the classical methods don’t work to explain so much of what we observe in nature, for me quantum mechanics are much closer to reality and therefore much more beautiful.

And that’s not to say you can’t use classical methods (they work quite well at a certain size and scale), but rather that newer methods are just that much better and more useful. I guess a good way to say that is that classical physics is somewhat false whereas quantum physics is a lot less false.

Build Your Science Brain: How not to learn quantum mechanics: things to avoid…

How do you know if you’re being suckered? In pop-science there can be a lot of woo about the quantum, but such pseudoscience and bizarre sham spirituality fails to prove anything. It can be extremely difficult to keep good messy science separate from the bad, but a good solid dose of skepticism goes a great distance (to quantum physics inventions like MRI machines, computers, the internet, lasers, the probabilistic nature of the universe, and much more). If you’d like to strengthen your science footing, then a great review to build your own internal bullshit detector is to read Carl Sagan’s “Demon-Haunted World” which remains one of the all time best places to learn how the sciences are different than pseudosciences.

A lot of bad writing on the quantum supposes that it has a mind or spiritual basis, which it doesn’t. For a reasonably good look at relationships to ideas of consciousness, a book who’s science isn’t completely wacky is Rosenblum and Kuttner’s Quantum Enigma: Physics Encounters Consciousness. Most physicists today have dropped the notion that the observer requires any consciousness at all — Orzel noted that the idea of a conscious observer “is so vague as to be unworkable and has mostly dropped out of real physics, but was picked up by a lot of, well, the sort of quasi-hippies… This has led to a lot of really crazy stuff being written about the role of consciousness in quantum physics and vice versa; this book is one of the few non-crazy takes on the subject that I’ve seen.” You can find some great recommendations for even more books at Orzel’s article at Forbes.com “Great Books for Non-Physicists Who Want to Understand Quantum Physics”.

See also Kaiser’s How the Hippies Saved Physics, and Amanda Gefter’s brilliant writing Trespassing on Einstein’s Lawn

I hope this post has given you a few ideas of where to begin. 🙂

And here is a rabbit basking in sunlight in our yard, which like all light includes many quantum effects: Rabbit-MagicHour-07192016web

 

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Thank you for reading.

If you enjoyed this post, please check my books online, such as Water Taxi in a River of Vampire Fish

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About The Author

Gregory Scheckler

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