Modern discovery in soft-matter physics

The 90th anniversary of Reviews of Modern Physics (RMP) is well celebrated in the February 2019 issue of Physics Today—for example, in the excellent review of the late 20th-century topic of soft matter (page 38 ) popularized by the authors of its references, notably Pierre-Gilles de Gennes. The authors of the last two RMP references worked in numerous European countries and in Turkey, India, and North America. Even so, I was struck by the article’s omission of a spectacular South American discovery in the 21st century, a discovery that in my view extends biologists’ 20th-century qualitative considerations far up to the quantitative level sought by physicists.

Although the discovery of fractals associated with the solvent-accessible surface areas of folded protein segments was made by two Brazilian physicists, Marcelo Moret and Gilney Zebende, ^{1 , 2} Lars Onsager’s 1944 work had shown that long-range interactions at phase transitions are best described with fractals. ³ Online protein data bases, including especially the genomic sequences data base, are by far the largest ever assembled. ^{4 , 5} The Moret–Zebende discovery of 20 precise fractals in complex protein structures has far-reaching implications, including the demonstration of Darwinian evolution in protein families. ² Such high precision immediately suggests that physicists may be able to achieve results of great medical value.