American physics implosion

Kannan Jagannathan’s review of two recent books ( Physics Today, December 2006, page 57 ) with the arresting titles Not Even Wrong: The Failure of String Theory … and The Trouble with Physics: The Rise of String Theory, the Fall of a Science … amusingly compares string theorists’ faith in their own transcendental insights to the Great Disappointment of 1844, in which religious leader William Miller and his followers renounced worldly goods and awaited the Second Coming. However, the tempest in a teacup surrounding string theory conceals a much larger problem in American physics. That problem is well illustrated by theories that have evolved over the past 20 years to describe high-temperature superconductivity (HTSC).

Since its discovery in 1911, superconductivity has fascinated many physicists. However, by 1980 the field was thought to be dormant; even the quest for higher transition temperatures T _c seemed to have leveled off around 30 K. In 1986 Georg Bednorz and K. Alex Müller announced that they had found superconductivity in a most unexpected place: not a metal, but a ceramic oxide, with T _c near 40 K. Within a few years, transition temperatures had climbed to well over 100 K.

Unlike string theory, HTSC was a field with abundant experimental information—today there are more than 65 000 publications on the topic, about one-third of them patents. Here was a real challenge for theory; no fewer than nine Nobel Prize winners, and many other scientists as well, have contributed theories on the subject. The question they raised most often was, What interactions are responsible for the high transition temperatures—the conventional electron–phonon interaction, as in the metallic superconductors, or something else? Of the nine Nobel laureates, three supported the conventional interaction, while six went for something exotic—usually electron–spin interactions. The experiments are now in, and the majority was wrong—the electron–phonon interaction is responsible.

Few readers will be surprised to learn that so many Nobel laureates were wrong. As they say on Wall Street, prior performance is no guarantee of future success. But now comes the interesting part—the three who were right are European, and the six who were wrong are American. That can scarcely be a coincidence, and it says something about American physics and especially what American professors and graduate students expect from research. Plainly stated, string theory and erroneous theories of HTSC may have a common explanation: Americans have become so self-centered that their physics theories are disconnected from reality, not only when no data are available, but even when experimental data are abundant.