I've remarked several times that I think condensed matter physics gets slighted in public discussions of the field, especially relative to its usefulness. Particle physics gets all sorts of press, but in practical terms, it is essentially useless-- whether CERN or Fermilab locate the Higgs boson or not will make absolutely no difference in the lives of the average person. Condensed matter physics, on the other hand gets basically no press, despite the fact that modern technological civilization would be impossible without an understanding of condensed matter physics.
(I should note here that my own background is in atomic, molecular, and optical physics, shading towards quantum optics, so I'm not saying this as a disgruntled condensed matter physicist. Quantum optics is also slightly over-represented in the media, relative to the practical impact it has, but not nearly as badly as high-energy physics.)
It's not hard to see why this happens. I have an undergraduate solid state physics book (Kittel) sitting on my desk, and about 25 pages in, it switches to the "reciprocal lattice" description of materials, a mathematical abstraction that no longer maps neatly onto the ordinary description of the world in terms of positions and momenta of individual particles. It's hard to tell coherent stories about the behavior of objects when you're working at that level of abstraction. Quantum optics and particle physics have a fair bit of mathematical overhead, but at the end of the day, you can still boil them down into stories about individual particles doing comprehensible things-- they're weird stories, but there's still a narrative structure.
The fundamental problem, here, is that condensed matter physics is dealing with huge numbers of particles-- 1023 or thereabouts. And dealing with more particles is extraordinarily difficult. Quantum optics and particle physics deal with one particle at a time, which is the only problem we know how to solve.
OK, strictly speaking, you can do exact solutions for two interacting particles. But you generally do that by using a mathematical trick to make the two particle system look like a one-particle system. For example, if you're dealing with two objects orbiting their common center of mass (a planet and its satellite, or a single electron and a positive nucleus), you can replace the two-particle system with a one-particle system in which a particle of a slightly lower mass orbits a fixed point. We know how to solve that problem.
As soon as you add a third particle, though, analytical solutions become impossible. There are some approximation techniques that you can use to get close to the right answer, but there's no way to construct a function that will always work to describe the three-particle system. There's no approximation you can use to get it down to just one particle, or even to two particles.
If the three-body problem is impossible, you can understand why the 1023-body problem requires so much mathematical overhead. Actually, in many ways, a system with huge numbers of particles is easier to work with than a system of three particles, provided you're willing to deal with statistical averages over the whole ensemble. You can get the bulk properties of a material without needing to know what each of the individual particles in the system is doing. This is the key realization that makes thermodynamics work, and something similar goes on in condensed matter.
The price you pay for this, though, is that it becomes extremely difficult to tell a non-mathematical story about the physics that gives rise to those bulk properties. That's not to say that there aren't useful narratives about those fields-- people in those fields talk about them using narrative in the same way that particle physicists and quantum opticians do-- it's just that the stories they tell involve the behavior of more abstract objects, that are several steps removed from the microscopic physics. That makes it really hard to tell a compelling story to someone who isn't familiar with the mathematical language.
(Similar problems crop up in high energy theory, as well-- the double-well picture explaining the Higgs is a good example, in which abstract things are moving in some potential whose origin is a little murky. They're not really central to the popular-level explanations, though.)
It's a tough problem. Given the essential role of condensed matter systems in the technology we rely on every day, it seems like there ought to be a market for popular-level explanations of this stuff. It's really amazingly difficult to explain at a pop-science level, though. Or, at least, it seems that way to me, my entire background in the subject being one grad-school class in Solid State, that I didn't do very well in.
(In a similar vein, there's remarkably little popular literature about chemistry, for similar reasons. Once you get more than a handful of atoms together, you need to start using abstract tricks to make useful predictions, and it becomes extremely difficult to follow. So you get a lot of writing about more basic stuff (physics) and more complicated stuff (biology), because it's easier to construct compelling stories out of small numbers of particles and cute fuzzy animals.)
I'd love to see good explanations of condensed matter physics at a popular level. A really good general audience cond-mat blog would be fantastic. I don't know of one, though. Doug Natelson is the best I know of, but as his most recent post notes, it's really hard.
Anyway, pointers to blogs and books, or suggestions of cool ways to understand condensed matter would be welcome. Particularly if you can suggest an angle that might make it make sense to the dog.
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You overlooked astrophysics, which also draws massive attention despite being of far less direct significance than condensed matter. I can fill the biggest lecture room on campus if I book an astrophysics seminar speaker. Condensed matter? Not so much. Hell, we had a biophysics speaker with "stem cells" in the title and we couldn't even half-fill the room. And this seminar was funded by a special program on campus which had a special constituency and hence we were guaranteed more than our baseline department attendance.
"... and particle physics deal with one particle at a time." Not to burst you bubble, but this is just plain wrong. As soon as one is relativistic, one has no choice but to deal with more than one particle at a time, and particle physics is relativistic.
Why do people always pick the number 1023 for an example of a large quantity? Is it because it equals 2^10 - 1?
(Kidding!)
It looks like you had a <sup> tag failure up there: you refer twice to a 1023 particle system when I think you meant 10^23.
@Alex: What astrophysics has going for it is, literally, pretty pictures. There are many astrophysical phenomena for which you can show a picture of a representative object and then explain why the telescope saw what it saw, without going into mathematical detail. Yet another case where a picture paints a thousand words ... or twenty equations.
Planetary science shares this characteristic (I have heard some people claim in jest that JPL stands for "Just Pictures Laboratory"). Cassini gets more publicity than most other NASA missions of comparable importance because it has a camera which can take pictures of Saturn's moons. Solar physics missions with imagers (SOHO, TRACE, STEREO) also tend to score well in the public outreach department.
As soon as one is relativistic, one has no choice but to deal with more than one particle at a time, and particle physics is relativistic.
Yes and no. You have to consider virtual particles and the like, but the fundamental stories that people tell to make the subject make sense to a general audience are single-particle stories. You have an electron, say, and it moves from here to there. Along the way, it interacts with all manner of other particles in a fleeting way, but as a practical matter, you only care about the one particle moving from place to place.
Why do people always pick the number 1023 for an example of a large quantity? Is it because it equals 2^10 - 1?
Because the superscript tag does not seem to be working. I wonder how the powers that be managed to break that. I will pass it on.
It looks like you had a <sup> tag failure up there: you refer twice to a 1023 particle system when I think you meant 10^23.
Annoyingly, if you look at the page source, the tags are right where they're supposed to be. For some reason, they don't render as superscript.
Actually, more isn't always more difficult. In fact, more can be dramatically more simple. Most often its the not-only-a-few but not-all-to-much-either case that's difficult.
Abstractness-of-narrative is only part of it, though. Condensed matter just isn't as "fundamental", and while it may make for better batteries for cell phones, it doesn't tell the layman anything about the universe we live in. Explaining neutrino oscillations through flavor and mass eigenstates isn't easy without some level of mathematical rigor, but people are interested because you can then talk about dark matter and other fundamental zingers. It's a "Wow" that they won't get from your stuff, sorry.
I still think AMO/CM is important and I'm glad you're doing it, I just don't anyone's going to be a rockstar like Stephen Hawking or Carl Sagan because of it.
Maybe condensed matter is just too familiar to people. If you start talking about semi-conductors, many people will recall that their laptops are made of such materials, so it isn't expected to be all that interesting.
http://scienceblogs.com/-/css/screen/reset.css
makes "sup" and "sub" (and lots of other things) have a font-size of 100%. I *think* that's where the problem lies.
I'm going to have to agree with Josh - condensed matter just seems more commonplace to people. There isn't the wow factor of saying "hey I'm figuring out how the universe started!" And AMO tends to impress with extreme precision, again something that most people can understand and be impressed by. Condensed matter just seems more mundane most of the time.
That's all the reason there is for why it's less popular. As far as actually explaining anything in all types modern physics to a lay audience, that doesn't happen at anything other then the extreme caricature level for anything. And condensed matter has plenty of those caricatures - photoelectric effect for example. Or how semiconductors work - electrons jumping in bands, etc. Both of those can be caricatured into single-particle problems about as well as anything in HEP.
And of course when it comes to doing actual work, most of condensed matter is far more intuitively accessible to anyone with some understanding of physics then HEP. I certainly can explain what I'm doing to a HEP friend more easily that they can do the reverse. All I'm doing is dealing with a bunch of electrons moving around. He needs to explain to me how the spin matters when two protons collide and create a thousand particles. There's no way to even talk about that without involving field theory.
Actually, particle physics is an (indeterminant) N problem.
I think condensed matter just hasn't had anyone do a good job of presenting it to regular people. There are cool pictures of the Fermi surface in a material. It is even the field where spontaneous symmetry breaking was first studied, wasn't it?
As for phenomena, I find that a demonstration of the Curie temperature is quite striking for any audience from general education on up. This example even has the advantage that it connects to geology (spreading rate at the mid-ocean ridge plus pole reversals).
Yes and no. You have to consider virtual particles and the like, but the fundamental stories that people tell to make the subject make sense to a general audience are single-particle stories.
Yes, particle physics is relativistic and therefore deals with more than
one particle at a time, full stop.
I guess you're just telling the wrong stories. Ya gotta juice it up some!
Until we have a fundamental theory of everything it's all just effective
field theories.
The only sexy thing about particle physics is that there one doesn't know
what happens as one goes to higher energies.
To address the superscript thing once more: In the rss feed, it is displayed nicely as you would expect it. Only in the browser will 1023 turn into 1023.
Oh, and superscripts do work in the preview, but not in the actual comments. The first 1023 above was meant to be 10^23, of course. Looks like the php processor's messed up.
Astrophysics does have cool pictures. But I suspect they don't communicate much. I think they're like fireworks. Viewers say "Oooooh!" and "Ahhhhh!" but understand little beyond how pretty it is. That said, pictures can be informative. I'm wondering if noe could use something like the demographic maps that came out post-Election -- the ones that don't show Redstates/Bluestates, but show how the country is really purple with a few isolated red & blue locales.
Maybe borrow from population biology popularizations? Like Wild Kingdom or Nat'l Geo. would show the entire Gnu herd migrating, but single-out a few to show meaningful & common individual outcomes.
Maybe the choice of example is important, as well? Instead of laptop batteries, talk about electric car batteries.
So, here's the problem I have as a person doing optics and biophysics and a bit of materials:
I'm always asked "What is that physics stuff good for anyway?" So I explain why physics is so important and useful, and people seem satisfied. But then they only attend the astrophysics seminars (and a few of the particle physics seminars). We have to move heaven and earth to persuade students (majors and non-majors alike) to sign up for upper division electives on applied optics or solid state or something else useful like that, but astrophysics is booked to the gills, both the GE version and the math-heavy upper-division version (which has more stringent prerequisites than applied optics or intro solid state).
You hear again and again that we need to make physics useful and applied and interdisciplinary and show how it's relevant to our technological society and all this high-minded stuff. Generally they toss in some language about how making physics more relevant will attract more [insert speaker's group of interest here] to physics. But then particle physics and astrophysics get all the interest.
Personally, as much as I love applied and interdisciplinary physics, I think that we're going to lose if we try to compete with the engineering school on the "Will this be useful in industry?" battle. Yeah, yeah, we have great arguments in our favor, but being right on the merits is not the same as being convincing to an 18 year-old. OTOH, with particle physics and astrophysics (and maybe, just maybe, nanotech) we can appeal to them on the coolness factor.
If you need an aspirin you get a chemist. If you need a headache you get a physicist. If the physicst has a headache he gets a chemist, then doesn't cite his source. "8^>)
I dropped Semiconductor Physics at that exact point in Kittel â the reciprocal lattice was the point we stopped talking about real atoms and went into some strange, incomprehensible land.
I took the same course taught by an EE professor the following semester (with his own lecture notes that glossed over the reciprocal lattice) and understood things somewhat better.
This isn't directly related, but you mentioned Chemistry, so I thought I'd point this book out that I think is great pop-sci Chemistry material.
http://www.amazon.com/Periodic-Kingdom-Journey-Chemical-Elements/dp/046…
Perhaps condensed matter is a victim of its own success, since technology based on it is so ubiquitous today that people don't bother anymore about the physics, but rather its applications as it applies to their daily lives. So I don't think it's a question of making it relevant - you can talk about nanoscale magnetics and how it relates to hard disk drives until you're blue in the face, but at the end of the it, what people ask for are comparisons on brands of hard disks and their costs. Even if you talk about the engineering aspects and challenges, the end result is the same. The physics/engineering just isn't relevant to how they can use the technology.
Whereas in astrophysics or particle physics, folks aren't distracted by technological applications, so they're better able to focus on the science and the philosophical questions that follow. And these topics aren't something they see every day, so there's also the novelty factor.
Familiarity breeds contempt, in a way.
It may be that condensed matter physics does not need to publicize itself much with support pouring in from industry, in contrast to particle physics or astrophysics which almost entirely depend on convincing a wider audience that they're worthwhile. And without the need, there's not as much practice ...
Actually, we still do need to advertise - while industry can certainly pour in cash (even today), skilled manpower is much harder to come by. Undergraduates still prefer to pick business, law or medicine rather than engineering or applied physical sciences.
I think astronomy has the opposite problem - too many astronomers, not enough funding. :D
I'm a condensed matter PhD student. I like my work, and I'd love to set up a blog about it - no-one outside of science knows how interesting, not to mention big and important, it is!
Half my problem is, at this stage I don't quite trust my own understanding of the stuff - certainly not to the point where I could make it sound as accessible and fascinating as it can be. (The other half is more to do with lack of time and writing practice.)
I've made a placeholder, and I hope I'll get around to it soon. But it's not easy. The few times that cond-mat work makes it into New Scientist in the UK - there was a writeup on graphene electronics recently, for example - it tends to be full of more oversimplifications that are needed for life science articles, and of course there's none of the all-out profundity, escapism or "wow effect" that cosmology and fundamental particle physics can play on.
And yet it's the bit of basic science that probably gives rise to more in the way of useful technology than any other. That must surely be the aspect that has PR appeal...
Thanks for the kind words, Chad, and sorry for coming late to the party. Someday maybe I'll have the skill (and the time) to write a consistently popular take on CM, as opposed to my intentionally more varied blog.
You and your commenters have hit the main issues. CM is inherently quantum mechanical and statistical, two areas where the general populace lacks decent intuition. Still, I think that there is some hope. Yes, explaining why copper is shiny is much less glamorous than claiming you're going to discover the "God particle". Still, claiming that CM is not "fundamental" (Stephen, I'm looking at you) is not a good reason for its lack of popularity. Plenty of fundamental ideas are resident in condensed matter, including spontaneous symmetry breaking, exotic statistics, charge fractionalization, etc.
Those readers who are not as scientifically well-read as Chad may not catch the reference in his post title to the famous essay by Philip W. Anderson, "More is Different", published in Science Magazine in 1972. In it, he persuasively argues for the fundamental value of understanding the behavior of many-particle systems, even when the laws underlying the interactions of the particles are understood. You can read it (warning, PDF) here.
Those readers who are not as scientifically well-read as Chad may not catch the reference in his post title to the famous essay by Philip W. Anderson, "More is Different", published in Science Magazine in 1972.
Don't give me too much credit. I remembered the phrase, but not the source. Had you asked me who said that, I probably would've guessed... David Mermin, most likely, just because Feynman would be too obvious.