Yaxin Li (Class of 2019)

What are you doing for your research project?

Before, I participated in research utilizing single-molecule Fluorescence Resonance Energy Transfer (smFRET) to observe the dynamics of Holliday junction, which is a cross-like structure that contains four DNA double-strands joined together. By combining FRET, which is valued for its distance sensitivity and utility in real-time observation, with high resolution fluorescence microscopy techniques, smFRET permits observation of dynamic and complex bio-molecular events, such as DNA/RNA-protein interactions. The goal of the project was to observe the dynamics of branch migration in Holliday junctions and to characterize the effect that protein binding may have on those dynamics.

During that project, I did smFRET part in Etson Lab, physics department and did Holliday Junction preparation in Mukerji Lab, MB&B department.

Now I am working in Kottos Group, physics department. My current project is about wave propagation in Multi-Mode Systems. For example, light propagation in Multi-Mode Optical Fibers.

In my research as an undergraduate research assistant, I have utilized a Random Matrix Theory (RMT) approach to unveil a physical mechanism that shields wave coherent effects in the presence of dynamical disorder. The RMT approach typically uncovers the most universal properties of wave transport in complex systems, and it can therefore serve as a good starting point for the understanding of designing schemes that protect the wave nature of propagation against noises and perturbations.

The dynamical disorder is characterized by its strength and correlation length. Also, it is known that propagation at distances larger than this correlation length will imitate a classical random walk process (in the mode space) where all phase-memory effects associated with wave transport are completely destroyed. Instead, we find out that there is a characteristic correlation-scale above which the light propagation is not affected by the “environmental” noise, but rather it is determined by the coherent wave transport occurring during the propagation along the first correlation length.

The conclusions of our study are relevant for a wide range of multi-mode (multi-level) physical settings, appearing in areas as diverse as mesoscopic optics, and matter waves to quantum electronics and quantum biology. These research results constitute the focus of a paper written together with Prof. Tsampikos Kottos and Prof. Doron Cohen. The paper was accepted by Physical Review Letters on March 29, 2019.

Why did you choose to major in CIS?

I chose CIS because it offers opportunity of summer research and academic discussions, which are the gateway experience to future academic career. The journal clubs and senior colloquiums require students to learn how to read a paper, how to do a presentation and how to put ideas into formal writing. CIS also offers generous funding for summer research.

What activities do you do on campus?

Before, I was in Chinese Culture Club and I practiced Kendo a little bit. But recently I am just focusing on my new project because it really has potentially huge impact in areas of physical sciences. Also, my research mentor really looks forward to seeing the results lol.

What are your plans after graduation?

Another year here as an MA student. I will try to finish the project and a paper on it. I need to take GRE and apply for PhD. After MA, 5 years of PhD, maybe…

How did the CIS-linked major help you at Wesleyan and how do you think it is preparing you for life after Wesleyan?

I got plenty of experience of presentation, academic discussion and writing. I could feel that I can convey ideas increasingly efficient, through presentations and writing. The summer research program also gave opportunity to get my hands dirty and to experience the real life of a scientist for summer long. The project with paper published was finished within one summer (I guess people are more productive during summer because there are fewer distractions, like homework, exams or club activities).

What do you do when you are not in the lab? (What’s your favorite hobby?)

Taking “random walks” around campus; playing video games; playing guitar; reading; sleeping a lot; eating in different restaurants in different cities… Recently I really like sleeping lol.