When Condensed Matter Physics Became King

If you are one of those, or know one of those, who think Physics is only the LHC and high-energy physics, and String Theory, etc., you need to read this excellent article.

When I first read it in my hard-copy version of Physics Today, the first thing that came across my mind after I put it down is that this should be a must-read for the general public, but especially to high-school students and all of those bushy-tailed and bright-eyed incoming undergraduate student in physics. This is because the need to be introduced to a field of study in physics that has become the "king" in physics. Luckily, someone pointed out to me that this article is available online.

Reading the article, it was hard, but understandable, to imagine the resistance that was there in incorporating the "applied" side of physics into a physics professional organization. But it was at a time when physics was still seen as something esoteric with the grandiose idea of "understanding our world" in a very narrow sense.

Solid state’s odd constitution reflected changing attitudes about physics, especially with respect to applied and industrial research. A widespread notion in the physics community held that “physics” referred to natural phenomena and “physicist” to someone who deduced the rules governing them—making applied or industrial researchers nonphysicists almost by definition. But suspicion of that view grew around midcentury. Stanford University’s William Hansen, whose own applied work led to the development of the klystron (a microwave-amplifying vacuum tube), reacted to his colleague David Webster’s suggestion in 1943 that physics was defined by the pursuit of natural physical laws: “It would seem that your criterion sets the sights terribly high. How many physicists do you know who have discovered a law of nature? … It seems to me, this privilege is given only to a very few of us. Nevertheless the work of the rest is of value.”

Luckily, the APS did form the Division of Solid State Physics, and it quickly exploded from there.

By the early 1960s, the DSSP had become—and has remained since—the largest division of APS. By 1970, following a membership drive at APS meetings, the DSSP enrolled more than 10% of the society’s members. It would reach a maximum of just shy of 25% in 1989. Membership in the DSSP has regularly outstripped the division of particles and fields, the next largest every year since 1974, by factors of between 1.5 and 2.

This is a point that many people outside of physics do not realize. They, and the media, often make broad statements about physics and physicists based on what is happening in, say, elementary particle physics, or String, or many of those other fields, when in reality, those areas of physics are not even an valid representation of the field of physics because they are not the majority. Using, say, what is going on in high-energy physics to represent the whole field of physics is similar to using the city of Los Angeles as a valid representation of the United States. It is neither correct nor accurate!

This field, that has now morphed into Condensed Matter Physics, is vibrant, and encompassed such a huge variety of studies, that the amount of work coming out of it each week or each month is mindboggling. It is the only field of physics that has two separate section on Physical Review Letters, The Physical Review B comes out four (FOUR) times a month. Only Phys. Rev. D has more than one edition per month (twice a month). The APS March Meeting, where the Division of Condensed Matter Physics participatesin, continues to be the biggest giant of annual physics conference in the world.

Everything about this field of study is big, important, high-impact, wide-ranging, and fundamental. But of course, as I've said multiple times on here, it isn't sexy for most of the public and the media. So it never because the poster boy for physics, even if they make up the largest percentage of practicing physicist. Doug Natelson said it as much in commenting about condensed matter physics's image problem:

Condensed matter also faces a perceived shortfall in inherent excitement. Black holes sound like science fiction. The pursuit of the ultimate reductionist building blocks, whether through string theory, loop quantum gravity, or enormous particle accelerators, carries obvious profundity. Those topics are also connected historically to the birth of quantum mechanics and the revelation of the power of the atom, when physicists released primal forces that altered both our intellectual place in the world and the global balance of power.

Compared with this heady stuff, condensed matter can sound like weak sauce: “Sure, they study the first instants after the Big Bang, but we can tell you why copper is shiny.” The inferiority complex that this can engender leads to that old standby: claims of technological relevance (for example, “this advance will eventually let us make better computers”). A trajectory toward applications is fine, but that tends not to move the needle for most of the public, especially when many breathless media claims of technological advances don’t seem to pan out.

It doesn’t have to be this way. It is possible to present condensed-matter physics as interesting, compelling, and even inspiring. Emergence, universality, and symmetry are powerful, amazing ideas. The same essential physics that holds up a white dwarf star is a key ingredient in what makes solids solid, whether we’re talking about a diamond or a block of plastic. Individual electrons seem simple, but put many of them together with a magnetic field in the right 2D environment and presto: excitations with fractional charges. Want electrons to act like ultrarelativistic particles, or act like their own antiparticles, or act like spinning tops pointing in the direction of their motion, or pair up and act together coherently? No problem, with the right crystal lattice. This isn’t dirt physics, and it isn’t squalid.

It is why I keep harping to the historical fact of Phil Anderson's work on a condensed matter system that became the impetus for the Higgs mechanism in elementary particle, and how some of the most exotic consequences of QFT are found in complex material (Majorana fermions, magnetic monopoles, etc...etc.).

So if your view of physics has been just the String theory, the LHC, etc... well, keep them, but include its BIG and more influential brother, the condensed matter physics, that not only has quite a number of important, fundamental stuff, but also has a direct impact on your everyday lives. It truly is the "King" of physics.

Zz.