I was sorry to hear that Pierre-Gilles de Gennes, the great French theoretical physicist, died a week ago last Friday, following a long struggle with cancer. De Gennes, who won the Nobel Prize for Physics in 1991, created much of our modern understanding of liquid crystals, colloids and polymers, essentially founding the field of soft condensed matter by recognising the common features of these soft systems characterised by interaction energies comparable to thermal energies and dominated by Brownian motion.
This obituary in Le Monde has a good account of his life and work. My first introduction to his work was at the very beginning of my PhD. When I asked my supervisor what I should do to begin my studies, he told me to go to the bookshop, buy a copy of de Gennes’s book Scaling Concepts in Polymer Physics, and come back when I had read it. I did this, and very good advice it turned out to be; it’s a book I still refer to. Soon after I had the chance of meeting the man himself , when he listened with absolute attention and politeness to what this insignificant graduate student had to say.
De Gennes was an erudite, deeply cultured and utterly charming man. One of his passions outside physics was art, and he used art history to illustrate how he saw the role of the theoretical physicist evolving in a time when computer simulations are becoming ever more powerful. Just as the invention of photography meant that artists no longer felt the obligation to strive for simple verisimilitude, and could seek to capture the essence of their subject in increasingly impressionistic and abstract ways, so the fact that systems of great complexity could now be simulated on a computer left theorists with the job of sketching a description of these systems in a way that puts insight and transparency ahead of perfect accuracy. As the attention of physicists turns more and more towards complex and difficult systems (including living things, the most difficult systems of all) this insistence on cutting through the thicket of detail to focus on the essentials becomes ever more important.