Uncomfortable Questions: Particle Physics

Posted on by Chad Orzel

Stephen asks:

Why do you try to hide your secret desire to be a high-energy particle physicist?

Heh. Seriously, honestly, I have no desire whatsoever to be a high-energy particle physicist. I wish I had a somewhat better understanding of particle physics, becuase that way I would have an easier time reading a lot of news stories and Cosmic Variance comment threads, but particle physics is not for me, for a variety of reasons.

The main reason is really that I like doing table-top physics. I like knowing that all of my apparatus is in one place, and under my direct control. I don’t have to wait for beam time, I don’t have to bend my schedule to anyone else’s. I do what experiments I want to, when I want to.

Also, I know the apparatus in my lab inside and out. Everything that’s there is something that I either put together myself, or watched a student put together under my supervision. If I want to change something, I can go in an change it, with maybe a quick look in the lab notebook to refresh my memory of what’s what. There are no huge complex systems that were built and maintained by somebody else.

I’m also happy with the scale of the problems I deal with. I have a good concrete picture of the physics of atoms and molecules, and it’s something that undergraduates can easily get their heads around. At the same time, there are some incredibly cool things going on in AMO physics– I think quantum information experiments are at least as cool as the search for the Higgs. I’m generally unmoved by fundamentalist arguments (i.e. “Particle physics seeks to answer the most fundamental questions of nature…” and all that rot).

Finally, I have an uneasy relationship with computers. I can program a bit, but it’s not my strongest suit. Experimental particle physics seems to be all about computing, really– you write code to sift through mind-bogglingly huge datasets to find the half-dozen events that you care about. I’d go nuts.

(I realize I’m implicitly excluding theoretical physics from this. That’s because I like having a job that pays my bills.)

So, no, I don’t have any secret desire to be a high-energy particle physicist. Experimental AMO is the right place for me.

9 thoughts on “Uncomfortable Questions: Particle Physics”

  2. Regarding “There are no huge complex systems that were built and maintained by somebody else.”

    Famous question at a PhD defense: What color is (piece of apparatus identified by name in the dissertation)?

    Experimental student did not know the answer, never having left the computer lab to actually set foot in the lab part of the lab. Committee ordered him to visit it.

  3. Regarding find the half-dozen events that you care about.

    If only there were so many expected events in my Higgs search!

  4. Uncle Al charitably launches your HEP career: What is the energy cutoff for cosmic ray protons interacting with Dark Matter re the GZK cutoff and photopion production? Official Truth demands a huge concentration of Dark Matter compared with cosmic microwave background photons.

    http://www.europhysicsnews.com/full/22/article2/article2.html
    Milky Way rotation curve implies dark matter density of 0.3 proton/cm^3 – a flux of several million neutralinos/m^2-sec crossing the Earth.

  5. There’s a good case that AMO is more fundamental than particle physics. Anyone with confidence in quantum field theory as anything but an approximation needs to go read the first section of Landau and Lifshitz, volume 4. Compare that realized gedankenexperimenten of modern AMO. And as more exotic symmetries show up in materials, it seems like quantum dynamics is being pushed faster in condensed matter than in particle physics.

    And then there’s the other side: playground fun, the kind of fun that derives from taking a physical system, and beating the living daylights out of it with all those tools from Landau and Lifshitz. For this, biology is not to be beat.

    (And this is coming from someone who’s childhood ambition was to build particle accelerators.)

  6. Pretty much off topic, but this was the latest science post.

    We were just forwarded the link to an insanely cool piece of software. A Java applet for modelling wavefunctions evolution in time. It deserves some attention.

    http://www.falstad.com/qm1d/

    This java applet is a quantum mechanics simulation that shows the behavior of a single particle in bound states in one dimension. It solves the Schrödinger equation and allows you to visualize the solutions.

    At the top of the applet you will see a graph of the potential, along with horizontal lines showing the energy levels. By default it is an infinite square well (zero everywhere inside, infinite at the edges). Below that you will see the probability distribution of the particle’s position, oscillating back and forth in a combination of two states. Below the particle’s position you will see a graph of its momentum. At the bottom of the screen is a set of phasors showing the magnitude and phase of the lower-energy states.

    To view a state, move the mouse over its energy level on the potential graph. To select a single state, click on it.

    You may also select a single state by picking one of the phasors at the bottom and double-clicking on it. Or, you may click on the phasor and drag its value to modify the magnitude and phase. In this way, you can create a combination of states.

    You may select a different potential from the Setup menu at the top right.

  8. I am a high energy physicist, and my first job with my advisor was working with a small setup that I could see. Playing with PMTs is fun. It was just calibration, but still, we get to play with real things sometimes 🙂

  9. I didn’t think this question was very uncomfortable, so I’ll ask it here. If someone were to hand you the keys to your own particle accelerator and you could do any experiment you wanted, what would it be?

    (Disclosure: this is research for a novel I’m working on. I’ve got a high energy physicist with an interest in the foundation problems of quantum mechanics, and she gets her own atom smasher, and I want to sketch out a plausible sounding experiment. Anyone who throws in an answer gets into the acknowledgements!)

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