Professor, Department of Physics
Thermodynamics and Statistical Mechanics of Small Systems
With interests ranging from the physics of liquid crystals to biological physics, Dr. Bechhoefer is one of SFU’s most versatile scientists. Recently, his research has taken a new direction: thermodynamics and statistical mechanics of small systems. Capitalizing on the control that can be exercised over small systems, Dr. Bechhoefer is testing principles that are central to traditional thermodynamics and statistical physics. In the 19th century, people thought about machines and developed thermodynamics to understand large systems, such as gasoline engines. With today’s technology, scientists can probe scales that are appropriate to biology (e.g., cellular level systems), necessitating a new kind of thermodynamics and theoretical physics to capitalize on what can be done in small systems.
What early life experiences influenced you to pursue a career in science?
As a five-year old, I wanted to be an astronaut, just like all the other kids who watched the Gemini and Apollo space missions; that dream morphed into an interest in astronomy. In high school I joined a summer science program attended by kids from all over the country. We had lectures during the day and in the evening we were tasked with calculating the orbit of an asteroid. That exciting experience drew me into science.
How did you go from studying astronomy to studying snowflakes?
I was an astronomy major as an undergrad, but I was also interested in history, philosophy, and science. In graduate school in physics, I became interested in nonlinear dynamics and chaos, a topic that is big now but was essentially unheard of in the early 1980s. My thesis looked at the equivalent of a snowflake in liquid crystals, such as those in the LCD laptop display, which are somewhere between a crystal and a liquid.
I gained a deeper understanding of why the crystals all look so different. Very small differences in their environment or trajectory will give differences in shape that are magnified as they grow; that's fundamentally the origin of why there are so many different types of snowflakes. And that sensitivity to conditions is exactly the mechanism of chaos.
How has your research program evolved since you started at SFU?
When I first came to SFU I worked on new dynamics and pattern formation, as well as problems of solidification and crystallization in liquid crystals and polymers. I continued with liquid crystals research but explored deeper questions about the nature of phase transitions.
Later, I learned about a new technique developed in the lab of a biologist who studied DNA replication. They put genomic DNA on a cover slide and looked at it under the microscope, stretching it in a way that allowed them to do optical mapping. They labelled the DNA to see when it was replicated, but they couldn't tell the difference between replications with one origin versus two origins or ones that started at different times. It occurred to me that the replicative process is analogous to what happens in crystallization. Guided by the calculations and mathematics used for analysing crystallization, we applied mathematics to DNA replication. One outcome of this very theoretical work was to develop great research tools for biologists.
An attractive aspect of my main focus now—thermodynamics and statistical mechanics of small systems—is the chance to do more lab experiments. Changing focus every few years can be a good thing because you're asking fresh questions.