Higgs Ripples in the Koi Pond

By Sean Carroll | May 10, 2012 10:31 am

On local TV last night, I somehow got reporter Dave Malkoff to take a stab at explaining quantum field theory: the world is made of fields, but we only notice the ripples within them, which we see as particles. Something about Angelina Jolie in there at the end as well.

  • Gizelle Janine

    Hahaha. This was great.

    1- Annoying: 30 people at once singing about science. (Unless it’s They Might Be Giants.) It’s a chorus so it’s 100 times more annoying…

    2-Newscasters in LA: Read the card!

    3-So why is everyone doing a Brian Greene, now? Did he really warp vectors in mid-air like you materialized an atom in front of that news nerd?

  • Jeff Johnson

    I enjoyed the report. What I find confusing is that there seems to be something circular in saying that the Higgs field confers mass upon particles depending on how strongly it interacts with them. If say a top quark interacts more strongly with the Higgs field than an electron, and thus has more mass, what non-massive thing is it that causes the Higgs field to more strongly interact with the top quark? If not mass, what is the property that distinguishes top quarks from electrons in their interaction with the Higgs field? It kind of says nothing to say “it’s because they are more massive” if their mass comes from the Higgs field.

  • H.

    Dr. Strassler has this to say about the respective masses of particles:

    “Why are these interaction strengths so very different? There is no consensus as to the answer to this question (which particle physicists call the “flavor problem” — referring to electrons, muons and taus as different charged-lepton flavors, and similarly for quark flavors). We hope the Large Hadron Collider might give us some insights here, but there is no guarantee that it will.”


  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean Carroll

    Jeff– Perfectly reasonable question. The answer is that “the strength of interaction” between two fields is something completely different, in general, from “the mass” of either of those fields. The strength of the electromagnetic interaction is specified by alpha, the fine-structure constant. Every massive elementary particle in the Standard Model has a specific strength of interaction with the Higgs field — nobody really knows where those numbers come from, but they seem to be constants of nature. It’s like the “Higgs force” is similar to the electromagnetic force, except that every different particle has its own version of the fine-structure constant. Those numbers would characterize the strength of the particle-Higgs interaction even if the Higgs were zero in empty space, and therefore the particles all had zero mass. But because the Higgs is not zero in empty space, the particles moving through it get mass, in an amount proportional to the interaction strength.

  • ellipsis

    Jeff: I’d like to emphasize the “nobody really knows” part of Sean’s excellent reply.
    We don’t know why, for example, the top quark has about 350000 times the strength of interaction with the Higgs field than the electron. It’s just one of the many different so-called hierarchy problems in modern physics that don’t have a known and tested answer yet. Maybe our discovering the Higgs and measuring its properties will give us a better understanding of why these differences have the scales that they have, or maybe we’ll also need to wait for other discoveries, or maybe both.

  • Uninvisible

    “Does the name ‘god particle’ irritate you?”


    “Well let me know when you find that god particle”


    (not exact quotes but you get the idea).

  • Drhack

    We should encourage people to call it the “goddamn particle” as Lederman wanted to.

  • http://3.bp.blogspot.com/_GqLiIYV1FnA/TIr8eWeZgrI/AAAAAAAAB6U/RIiNR60WdvQ/s1600/HHGTTFSC.jpg J. Harvey

    The Fine Structure Constant can be derived exactly from other well-known constants.



  • Uninvisible

    Drhack : consider it done.

  • Chris

    You said if there was no Higgs, there would be no atoms. But even if the proton and electron were massless they could still be attracted and form a massless atom. Although it is definitely very weird to think what that would look like since all our charged particles carry mass. You’re going to leave me with a headache.

  • Jeff Johnson

    Sean, thanks for the response. Thanks ellipsis and J. Harvey as well.

  • Eric Habegger

    I think I caught A glimpse of Ron Bergundy at the beginning and end of the video. Good to see him again, and in such fine form too.

  • http://www.theory.caltech.edu/%7Epreskill John Preskill

    Be sure to include this in the book:

    top quark is to Higgs field
    Angelina Jolie is to … what?

    It’s too bad they removed the analogy questions from the SAT.

  • Jesse M.

    As another way of addressing Jeff’s question, isn’t the fact that particles interact differently with the Higgs field supposed to have something to do with the idea of spontaneous symmetry breaking shortly after the Big Bang? In other words, didn’t the universe start out with the Higgs field in a state where all particles interacted with it in a perfectly symmetrical way, then after the Big Bang, as the temperature started to go down, it decayed in a random way (via the Higgs mechanism) to one of many possible lower-energy equilibrium states, each of which would give the particles different masses and the forces different strengths? That was my layman’s understanding of the current theory anyway. I’ve seen the analogy to the direction of spins of atoms in a magnetic material, where if the magnet is at a high temperature all the spins are aligned randomly so the magnet is over all symmetrical with no magnetization, but then as the temperature lowers (below the Curie temperature) the spins all spontaneously line up with each other (at least in small regions called “magnetic domains”), breaking the symmetry and creating a magnetic field in a randomly-determined direction.

  • Truth

    @Chris, a massless electron would travel at the speed of light. it could be deflected by the proton, but would not stay bound to it. so atoms would not exist.

    But quite frankly, this is a very obscure way of describing what the Higgs does. there are many reasons atoms exist besides the electron having a mass. This includes the existence of the electromagnetic force, and its related 1/r^2 attractive force, the properties of quantum mechanics which allows the atom to be stable, the existence of the positively charged nucleus, the strong force to hold the nucleus together, QCD to endow the nucleus with mass, the incredible weakness of the weak force so rapid decay doesn’t occur, etc. For Sean to say that the primary consequence of the Higgs is to allow atoms to exist is quite misleading and confusing to most people, I am sure

  • http://gnomonicablog.com Fernando Curiel

    Sean is right as far as science is concerned. And everybody should enjoy the explanations, Jolie style and all, even if they are not at the level that each particular person expects. Even hard core scientific explanations have to live with some level of ambiguity and all physical models leave questions unanswered. It is about time we stop thinking the explanations have to have zero holes in it all the time. No theory could probably do that ever… Our models are constrained by what is within the space of your ears. Again, enjoy the different level and scopes of the explanations. How would you have done it?

  • Brett

    I imagine Cosmic Variance to be similar to the cast of the Big Bang Theory. Which one of you is the closest to Sheldon Cooper?

  • Charles Turner

    On understanding time and it’s unique properties the whole Theory of everything unfolds into two NEW PHYSICS LAWS.
    1). All mass & energy decay via electromagnetic fields into continuous gravitational waves. Note; as mass and energy evaporate into space, stars add the exact amount so there appears to be no process going on.
    2). When inphase waves create wavefronts the reaction affects the tension between the sources: this is gravity.
    Time and space are actions of law #1 and gravitation is the action of law #2.

  • Big G

    Could you clarify how “Space” is defined within QFT? I’ve heard LQG theorists and particle physicists claim the fields of QFT can be thought of as “on” or “above” space and existing at every point in space — but is that space similar to the “spacetime” of relativity? Does it have any structure, as in LQG? Or like Smolin’s “simplexes?” And if it does have structure, is it purely an abstract construct or representative of something that actually exists (not “exists” in a metaphysical sense, obviously, but “exists” like the fibers, etc of the fields).

    I’m aware that’s a lot of questions and maybe too much to ask in the comments, so … yeah. I’m not going to be offended if that’s not answered.

    Love the blog.


  • Bob

    Big G, yes space exists like the ” fibres” of the fields. Why? Because space is described by a field, called the metric field. It is dynamical, like the electromagnetic field, it can support gravitational waves. It can bend and contort, giving rise to gravity. It can be quantized leading to particles called gravitons.

    In summary, the metric field which describes space is real, every bit as real as the electromagnetic field.

    By the way, you should study general relativity to understand this. Don’t worry about nonsense like simplexes, etc.

  • Big G

    Thanks, Bob, that clarifies a great deal. It seemed that if it wasn’t real then the whole notion of “space” became superfluous in QFT, and I assumed that couldn’t be the case, so I had to be missing something. Much obliged.

  • Eric Habegger

    Bob, you are right about space being a metric field. I would suggest that it often more profitable to identify it as a type of electromagnetic field, or rather the ground on which the observable electromagnetic field is formed. We know that both the gravitational and electromagnetic fields are fields that act at a distance. That is a very good evidence, along with other circumstantial evidence, such as the fact that when a black hole evaporates its decreased gravity is a result of a loss of photons, not gravitons, that they are related.

    If you decide to accept that gravity and electromagnetism are related then what could it be that creates the huge disparity of strength of forces between the two? I think it is that space consists basically of an unorganized and finite electromagnetic field. Anytime you accelerate a composite particle you are organizing this random field, just as you would by drawing a line in the dirt with a stick. By accelerating that particle you are reversing entropy within that random field and the change in entropy before and after determines the strength of the force. Force is a measure of the inertial resistance to the change in entropy of this random electromagnetic field. The photon is the force carrier that creates that change, not the graviton. The graviton is to the random electromagnetic field what a phonon is in solid state physics. It is not a force carrier but something that can be modeled as if it were.


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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .


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