Prof. Sung Jae-young / Prof. Kim Ji-hyun / PhD Student Song Sang-geun

Prof. Sung Jae-young, Prof. Kim Ji-hyun and PhD student Song Sang-geun of Chung-Ang University solved one of the most difficult problems in statistics physics that has not been able to be solved even by Einstein’s Brownian Motion theory. 

Their research team came up with a new transport equation applicable to transport dynamics of atoms in complex fluid systems such as living cells. Brownian motion refers to a random movement of particles in a fluid, of which one of the cases in point is petals floating on the surface of water. Einstein suggested an equation that can predict in which way particles will move. However, his equation is not applicable to small particles and disordered fluid systems, which has made explaining Brownian motion one of the hardest questions to solve in modern statistics physics.

The research team derived a new transport equation from a random walker model in which dynamics of walkers change depending on the surrounding environment. The team members proved that their new equation provides an exact, quantitative description of various anomalous transport.  

Original Random Walk Model and New Continuous-time Random Walk Model [Provided by NRF]

“From our research, we derived an equation and its solutions that can provide a unified explanation of Brownian motion and transport dynamics of complex fluids, which has been one of the most difficult problems in statistics physics,” said Prof. Sung when he was talking about his team’s follow-up research plans. “We are planning to use the equation to better understand and predict various life phenomena that occur by enzymes and biopolymers of living cells.”

The research was conducted as a basic research project supported by the National Research Foundation of Korea and was published by the Proceedings of the National Academy of Sciences (PNAS) on June 11.