A recommendation

Billy approached me to write her a recommendation letter. I replied without hesitation that I would absolutely recommend her. My response was more instinctual than rational. It seems I wholeheartedly approve of Billy, but it takes a little more effort to crystallize exactly what it is I approve about her.  

Over three semesters within the last three years, I have taught Billy three courses in physics, as a teaching assistant. One of my roles has been to conduct problem-solving sessions, where I organize students into discussion groups to solve problems together. Her attendance record is outstanding, the best among her colleagues. What is more impressive is that she grasps intuitively the point of these sessions. Solving a difficult physics problem is like a random walk in the space of ideas, where the meandering is more important than the destination. Somewhere along this meandering, one must actively discard one premise for another, actualize vague uncertainty into concrete mathematical and physical reality. To stumble upon the final solution uncritically is to cheat, one lives under an illusion of triumph, without realizing how thin the foundations on which one stands. Often Billy would approach me, with a thoughtful, often difficult, question. We like each other’s styles, because I would nudge without revealing the final solution, and she doesn’t want it anyway, preferring to arrive at it through her own meandering pathway.

Temperature is one particularly difficult concept taught in any statistical mechanics class; it is tricky because somehow one must relate the intuitive notion of hot vs cold, to more abstract ideas such as a microstate. In short, a microstate is a particular configuration of the microscopic constituents that make up a macroscopic system. I recall after one spirited discussion, we concluded that temperature as conventionally defined is a rather awkward device, and a more natural quantity to study is the inverse temperature. We both left our discussion with a sense of joyful wonder, a sense of history and what-if.  

Such meditated thoughtfulness has led her to a deep understanding of physics, and it does not surprise me that she has topped each of the three classes that I have taught. She is drawn to subtlety, to ideas that resonate universally, in physics and beyond. She explained to me that the theme of randomness ubiquitously permeates different modes of thought. The heart of statistical mechanics lies in correctly treating the randomness of microstates. In juxtaposition, she shared with me a short story, by Borges, who wrote of an institutionalized lottery in Babylon that rules the lives of its citizens through chance. 

Billy’s tendency to meditate on deep ideas does not preclude action. She is infused with practicality, with the desire to translate her research into solutions that matter outside the physics community. Fusion is one such solution, and has been at the center of her research efforts for years, both locally in Princeton and internationally in the Netherlands. For the future in the UK, she has set her sights on the Joint European Torus, an important fusion-related experiment. Her interest in fusion has two facets. When I ask her about the science of fusion, I am treated to a torrent of information and passion, about intimate details in the workings of a tokamak, about various ways to confine a plasma. On the other facet, she is just as enthusiastic in discussing the politics of energy and the environmental ramifications of using fossil fuels. This marriage of scientific intelligence and political astuteness is inspiring to witness.