Wednesday, August 25, 2021

The emergence of condensed matter as a fundamental force in physics

What shapes the emergence and influence of a specific new academic discipline or research field? How much does context matter?

How is the discipline defined? By the objects studied, methods used, central concepts, questions asked, goals, or key discoveries? And, who gets to define the discipline: text-book authors, current researchers, distinguished academics, or university managers?

It may depend on who you ask. A discipline can be viewed from intellectual, historical, institutional, political, economic, and sociological perspectives. It all depends on what questions you ask.

Arguably, for most of the twentieth-century physics was considered the dominant field of science. We also observe today that condensed matter physics is a dominant force in physics. This is reflected in many different measures, such as numbers of practitioners, journal articles, PhDs, citations, and Nobel Prizes.

How did this happen? 

Joseph Martin is a historian who explores this question in his 2018 book, Solid State Insurrection: How the Science of Substance Made American Physics Matter. He looks particularly at physics in the USA in the political and economic context of the Cold War, focusing on the rise of solid-state physics, and its metamorphosis into condensed matter physics. The role of institutions such as government, industry, and the American Physical Society (journals, conferences, divisions) is carefully examined. Public testimony of Phil Anderson against the SSC (Superconducting SuperCollider) in 1989 is considered to be a watershed moment and highly symbolic. 

The book is carefully researched, beautifully written, and contains important new insights. I highly recommend it.

In exploring these issues I think it important to find a balance between two extremes. On the one side, there are purists and idealists who claim that physicists are the best (or even only) people to provide a useful and reliable perspective. Science is all about reality, facts, and truth, and contexts (social, political, economic) are completely irrelevant. At the other extreme are the social constructivists who think science is just about politics and power, both inside and outside the university community. Martin is to be commended that he does not tend towards either of these extremes.

A Physics Today article is adapted from the book When condensed-matter physics became king and gives a useful summary.

To whet your appetite for the whole book, a good place to start is the concluding chapter. Martin offers two fascinating counterfactual histories: one where the Manhattan Project failed, one where APS did not keep industrial physicists in the fold.

the most active frontier of the twentieth century was not the high-energy frontier, but the complexity frontier. It was the demystification of the properties of complex matter and the applications of those properties, which remade our technological world, from home computing, stereo equipment, and cookware to communication, transportation, medicine, and warfare.

This is a tendentious framing, but it serves a purpose: it exposes the historiographical contingency of the disproportionate focus on nuclear physics, high energy physics, and cosmology, alongside the historical contingency of the dominance those fields assumed over public discourse about physics in the second half of the twentieth century. Two counterfactual scenarios help to probe that contingency further, each of which offers heuristic utility by throwing into relief the role solid state physics played, despite lacking the public acclaim of its sibling subfields, in securing the prominence of American physics.

First, given the high degree of institutional volatility in the early post–Second World War era, it is easy to imagine a counterfactual scenario in which solid state physicists migrate away from physics and into chemistry, metallurgy, and engineering, much as electrical engineering had some decades earlier. It was a contingency about which the field’s founders actively worried, and the American Physical Society council was demonstrably squeamish about clearing the type of institutional space that would give the society a more industrial flavor. Without solid state, which accounted for a large proportion of the postwar population boom, physics would have stayed smaller and grown more slowly.

We can imagine a second counterfactual scenario in which the Manhattan Project never acquired the scale or resources it needed to construct a working bomb before the end of the war in the Pacific... Suppose, for whatever reason, the Second World War ends without a dramatic, public demonstration of the power of the nucleus...  In this second scenario, solid state physicists would have been well positioned to become much more politically influential in the early Cold War, in particular on the strength of radar research,..

Aside. Earlier I posted about a nice article Martin wrote about public perceptions about condensed matter physics.

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