Physics (Internal)

Insights into Single Molecule Dynamics

This event is part of the Biophysics/Condensed Matter Seminar Series.

Abstract:
Recent advances in technology have enabled studying the dynamics of single molecules. What new
insights can be revealed by these experiments which cannot be seen in bulk measurements? In this talk. I will focus on two examples where we showed that studying single molecules reveals new phenomena. The first is the case of anomalous diffusion in an equilibrium environment. I will discuss a few models for anomalous diffusion where weak ergodicity breaking emerges. The concept of weak ergodicity breaking will be clarified and I will discuss how it enables us to distinguish between different models for anomalous diffusion. The second example I will discuss is a non-equilibrium system, a single molecule excited by a monochromatic laser field. I will introduce the moment-generating function for photon emissions in which the frequencies of the fluoresced photons are explicitly considered. Calculations were performed for the case of a two-level dye molecule, showing that measured photon statistics will display a strong and nonintuitive dependence on detector bandwidth. These two examples show that single molecule measurements can provide new information about the observed system both in equilibrium and non-equilibrium conditions. Moreover, new phenomena which are observed only at the single molecule level can favor certain microscopic models over others.