Condensed concepts

 My economist son often listens to the podcast, Conversations with Tyler Cohen. We recently listened to a conversation with Esther Duflo , who shared the 2019 Nobel Prize in Economics. Like most episodes it covers a wide range of territory, from development economics to Indian classical music to parenting. I highly recommend it. Perhaps, the bit that was most striking for me was the following. What advice do you give to your talented undergraduates that differs from the advice your colleagues would give them?    I give almost all of them the advice to take some time off, in particular if they have any interest in development, which is generally the reason why they come to see me in the first place. But even if they don’t really, to spend a year or two in a developing country, working on a project. Not necessarily inner city. Any project spending time in the field.    It’s only through this exposure that you can learn how wrong most of your intuitions are and preconceptions are.

I was sad to hear last week of the death of John Wilkins . He was a mentor to a whole generation of condensed matter physicists and a generous servant, both individuals and institutions. This obituary and memories from some colleagues gives a nice description of his many contributions. I was privileged to do a postdoc with Wilkins at Ohio State University in the early 1990s. He had a significant influence on me, both scientifically and professionally. Much of the practical advice I write on this blog relating to jobs, writing, and giving talks, I learned from Wilkins.  Even ten years after I worked with him I would still occasionally phone him for advice, particularly with negotiating and deciding on job offers. Real leadership does not involve having a position, but rather having influence. Servant leaders  are not concerned with advancing their own interests, but rather those of others in their community. They do this by investing in people and institutions. Wilkins did this in

Last night I heard a model public lecture about science. The School of Mathematics and Physics at UQ hosted a public lecture at the Queensland State Library. Holly Krieger , a pure mathematician at Cambridge, spoke on the Mathematics of Life. This is part of a biannual lecture series endowed by Kurt Mahler. The lecture was amazing, both in content and presentation. It was engaging for high school students, and stimulating for experts. I wish I had a video or a copy of the slides. Krieger is well known to some through her Numberphile videos on YouTube.  Here are a few things I learned in the lecture. Mathematics is the language of relationships and patterns. We forget how even the concept of numbers is abstract. The notion of functions is even more so. An underlying theme of the lecture was that of emergence : a simple rule describing the interactions between the components of a system lead to collective behaviour (complexity) of the whole system. Examples were given from biol

Following the fall of the Berlin Wall, one incredible revelation was the expansive role of the secret police, vast network of informers, and level of personal surveillance. This was underscored to me in movies such as The Lives of Others , novels such as The Day of the Lie , and a seminar I attended about human rights abuses in Syria. The survival of totalitarian regimes is facilitated by the regime creating a culture of fear at every level of society and institutions, from factories to families. You do not dare to question or criticise the regime. Even making a joke at work may send you to the gulag. Over the last decade, I have noticed a cultural shift in universities where there seems to be a culture of fear in many different aspects. A few examples are below. I should be clear that I am not suggesting that universities today are anything like Syria, China, or the former Soviet Union. Nevertheless, it is worth reflecting on whether there is a culture of fear and what its impli

The Ising model is a paradigm in both statistical mechanics and condensed matter physics. Today for most theorists it is so familiar that some of its historical and conceptual significance is lost. Previously, I posted about what students can l earn from computer simulations of the Ising model. If you had to talk about the Ising model to an experimental chemist what would you say? [Last week I had to do this]. The Ising model is the simplest effective model Hamiltonian that can describe a thermodynamic system that undergoes a first-order phase transition and has a phase diagram containing a critical point. On each site i of a lattice one defines a spin sigma_i= +1 or -1, representing spin up or spin down. The Hamiltonian H is J_ij describes the interaction between spins on sites i and j. In the simplest version the interactions are only between nearest neighbours, and have the same value J. h is the external magnetic field. If J is positive, the ground state at h=0