Condensed concepts

How do you define a distinct scientific discipline? Should it be defined in terms of the subject of study, methods used, concepts, goals, history, and/or sociology? Who gets to decide the definition: the practitioners, a broader scientific community, or administrators? How clear do the boundaries between disciplines need to be? And, does it really matter? Condensed matter physics has a close relationship between materials physics, both intellectually and organisationally. The flagship journal Physical Review B has the subtitle "covering condensed matter and materials physics". The largest physics meeting in the world is the American Physical Society March Meeting which is largely organised by two APS divisions, those of Condensed Matter and Materials Physics. According to the APS website The Division of Condensed Matter Physics Originally called the Division of Solid State Physics (DSSP), the unit was formed in 1947, the third society division. In 1978 the DSSP was renamed th

A beautiful and profound article, Superconductivity and the Quantization of Energy , by D.G. McDonald was published in Science in 1990. Ideas about quantized energy levels originated in atomic physics, but research in superconductivity has led to unparalleled precision in the measurement of energy levels. A comparison of levels produced by two Josephson junctions shows that they differ by no more than 3 parts in 10^19 at an energy of 0.0003 electron volt. The fact that the myriad of interactions of 10^12 particles in a macroscopic body, a Josephson junction, can produce sharply defined energy levels suggests a dynamical state effectively divorced from the complexities of its environment. The existence of this state, the macroscopic quantum state of superconductors, is well established, but its isolation from intrinsic perturbations has recently been shown to be extraordinary. These new results, with an improved precision of about ten orders of magnitude , are discussed in the contex

Writing a paper is hard work. Writing a paper that is clear, engaging, and accurate is even harder. After you have written a draft or are reading a draft of a colleague or co-author I think the following discipline is important and worthwhile. Go through every sentence and ask, is this true? Is it precise and accurate? Let me illustrate with a concrete example. Consider the following different claims. The experiments of Jones et al. proved that GaAs quantum wires are Luttinger liquids. Jones et al. interpreted their experimental results on GaAs quantum wires in terms of the framework of Luttinger liquid theory. Jones et al. fit their experimental data for the temperature dependence of the resistivity of a GaAs quantum wire to a power law, such as predicted by Luttinger liquid theory. Jones et al. showed that their experimental data was inconsistent with Fermi liquid theory, but consistent with Luttinger theory. Hopefully, the differences between these claims are clear. This discipline