• Question: (As a teacher testing out the student side) How did you first get moments of really grasping how particle physics and quantum mechanics work? This is something that seems very far off in year 12... Any books, videos etc you can recommend?

    Asked by anon-345964 on 20 Dec 2022.
    • Photo: Benjamin Rienacker

      Benjamin Rienacker answered on 20 Dec 2022:


      Around the year 2000, when I not yet had heard anything about quantum mechanics and particle physics, the word “quantum” as in “quantum leap” meant something really huge and important to me. Well, that is how we use the phrase, so nothing wrong with it. However, now I think it is kind of a funny choice, because technically it means “the smallest possible step” in any process imaginable.
      In school, the concepts of quantum mechanics was introduced by demonstrating the ambigious results from light interactions: light’s wave character in a double-slit experiment and light’s particle character that is needed to explain Compton effect (inelastic collisions of light particles [photons] with free electrons) or the photo effect (only one entire photon can release one electron from a metal surface). So the conclusion: Light is both, wave and particle, and that’s that.
      This left me mildly dissatisfied, so I started to ask questions (to my teacher): How can it be both – wouldn’t that rather indicate that we don’t understand something, like, fundamentally? – “Er, well, probably yes”. So what happens when you use light so weak that a photon detector only finds a single photon at a time, and you put now a double-slit in the light’s path – do we see any wave-like behaviour? – “Indeed, we do. It has been tested over and over again. And by the way, this is also true for other particles, like electrons. They can also behave like waves when sending them through a narrow slit, and so can elefants if you send them under a bridge fast enough. Have you ever heard of Heisenberg? De Broglie?”
      To me, this was the beginning of a journey, and even after quite a bunch of years of studying and experimenting, I feel like I have only gotten closer to asking more meaningful and precise questions. The answers elude me, though.
      A book that I really appreciate in this regard is a satirical history of quantum mechanics that sums up our current understanding of the topic well: “Fundamental”, by Tim James.

    • Photo: Jonathan Edward Davies

      Jonathan Edward Davies answered on 3 Jan 2023:


      You’re right that these topics are quite difficult to get your head round and it takes a few University courses to really get to grips with them- if then. Quite a lot you just have to take as given and accept that a lot of the ideas will sound a bit crazy.

      I was inspired by the discovery of the Higgs boson in 2012 when I was 14. I first came across the basic concepts just by going down Wikipedia rabbit holes. We talked a little about Quantum Physics and Particle Physics at A-level but not to the level of detail that satisfied me. A good book on Particle Physics that I was given by my A-level teacher when I was in year 13 was The Cosmic Onion by Frank Close, though it is quite technical and I found it harder to follow after the first few chapters so perhaps not one to start with. The guy that does YouTube videos for Fermilab’s channel I think is quite good at explaining big concepts simply and, though I completely disagree with a lot of what she’s been saying recently, apparently Sabine Hossenfelder also explains things well. Veritasium is a very good channel to check out as well. When I was younger I read a couple of books by Jim Al-Khalili (whom I would recommend generally) on Quantum Mechanics- “Quantum- A Guide for the Perplexed”, and “Life on the Edge”, which is about Quantum Biology and also had an associated TV series. I think I picked up a fair amount from reading New Scientist as well. On YouTube there are also great videos from the Royal Institution.

      I hope this helps, and you or your students are more than welcome to pop a message here for any other questions you might have.

      Finally, as a shameless plug I took part in the Pint of Science festival (online) in 2021 in a session dedicated to explaining current particle physics to the general public-

    • Photo: Joel Goldstein

      Joel Goldstein answered on 17 Jan 2023:


      I certainly have specific memories of major leaps in understanding: qualitatively from reading popular science books as a kid, more quantitative and substantial as an undergraduate (or later) often triggered by a particular point in a lecture or working through and really understanding a problem.

      When I was young, I was a big fan of Isaac Asimov’s essays. I borrowed them from my dad’s bookshelf so they were already rather out-of-date and I doubt the science has held up well (although of course they were well-written).

      These days I don’t read or watch a lot of popular science, but I do remember enjoying Jim Al-Khalili’s short TV series on quantum mechanics a few years ago.

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