I was born and grew up in Hong Kong, one of the most densely populated cities in the world. I have enjoyed the thinking process and often tried to get to the bottom of things since I was young. Naturally, I fell in love with physics when I first learnt the subject in high school. I studied physics and mathematics at the University of Hong Kong, the first university established in Hong Kong. In my final year of undergraduate studies, I felt that I still had the capacity to learn more and had the idea of going abroad for graduate studies in theoretical physics. Yet, I did not have any concrete plan of becoming a professor at that time. Being unfamiliar with universities abroad, I asked my high school physics teacher, who once mentioned his attempt to pursue PhD studies in the US, for suggestions of universities to which I could apply. Instead, he told me that studying a PhD degree is a huge investment in time and effort, and doing so purely because of the love of learning is not a wise move. Thus, I decided to pursue MPhil studies to try out research. At that time, there were only two universities in Hong Kong, and I went to the other one, the Chinese University of Hong Kong, for a change in environment. During my two years of MPhil studies, I learnt how to do research and published my first two papers under the guidance of my supervisors, Kenneth Young and Hon Ming Lai. It became very clear to me that I enjoyed doing research and being a professor is the career that I would like to have. Then I applied for PhD studies in the US. I got a few offers, and eventually decided to go to the University of Chicago.

When I told my parents my plan to study abroad, they, however, did not support my plan. My mother and grandmother tried to talk me out of my decision. My parents were worried as I had never traveled overseas, and they also had this traditional Chinese thinking that it is not good for women to have too much education. While my MPhil supervisors were supportive and wrote recommendation letters for my applications, there were other professors who made discouraging remarks. A professor from China told me that I would be too old to compete with the young students who graduated from the Special Class for the Gifted Young, an early college entrance program in mathematics and science in some universities in China. Another professor at the Chinese University of Hong Kong said that the society does not need female theoretical physicists. Nevertheless, I did not change my mind, and I went to Chicago after receiving my MPhil degree in 1988.

At the University of Chicago, my PhD advisor Leo Kadanoff introduced me to the problem of fluid turbulence. I was given the task to analyze temperature measurements taken in an experiment on turbulent Rayleigh-Bénard convection by Albert Libchaber’s group. These analyses resulted in two single-authored papers. One particularly interesting result is my finding of two closed-form expressions for the probability density functions of temperature fluctuations and temperature differences between two times. After graduating from the University of Chicago in 1992, I went to the (Kavli) Institute for Theoretical Physics at the University of California at Santa Barbara for my postdoc, during which I worked with James Langer on dynamic fracture. Then I returned to Hong Kong, joining the Department of Physics of the Chinese University of Hong Kong, where I am currently a full professor.

Figure 1. With Leo Kadanoff in Hong Kong (1996).

I am continuously fascinated by fluid turbulence and have worked on different problems including anomalous scaling and intermittency of turbulent fluctuations, statistics and scaling in turbulent Rayleigh-Bénard convection, extraction of coherent structures from velocity and temperature measurements, turbulent drag reduction by polymers, effect of polymers on heat transfer in turbulent thermal convection, boundary layer theory for turbulent thermal convection, and heat transfer and wall shear stress in turbulent vertical convection between two vertical walls at different temperatures. Currently, we are working to understand analytically the heat and solute fluxes in turbulent multi-component vertical convection. This problem is especially interesting as the ratio of heat and salt fluxes at an ice-ocean interface plays a direct role in determining the ice-ablation rate in polar oceans.

Besides being fascinated by fluid turbulence, I am intrigued by how the brain works. It is believed that the knowledge of connectivity or wiring patterns of neurons in neural circuits in the cortex could give us some clues. However, connectivity of cortical networks or networks in general cannot be easily measured. Thus, we started to work on the problem of network reconstruction and have developed methods for reconstructing networks from dynamics of the nodes. We have applied our method to extract connectivity of cortical neuronal culture from voltage measurements taken by a multi-electrode array. Recently, we have numerically studied the dynamics of networks of adaptive excitatory and inhibitory neurons subjected to stochastic inputs. Our study shows that a state of coherent bursting, with power-law distributed avalanches and features like those observed in in vitro and in vivo experimental measurements, emerges when excitation is sufficiently strong and yet small enough to be balanced by adaptation. This result sheds light on the possible conditions for the power-law distributed neuronal avalanches observed in spontaneous brain activity to occur and contributes to the ongoing debates on the critical brain hypothesis.

Looking back after all these years, I am pleased that I made the decision to pursue graduate studies abroad and how this decision brought me, step-by-step, to where I am now. The message that I hope to convey to the young readers is to follow your heart and do not let others define or confine what you can do.