In turbulent fluids, mixing of the components happens easily. However, in more viscous fluids such as those enclosed within cellular compartments, the intermixing of particles and molecules is much more challenging. As time also plays a role in such systems, the slow mixing by molecular movement is typically not sufficient and efficient stirring strategies are thus required to maintain functionality.

In the department of Living Matter Physics at MPI-DS, scientists investigated the universal physical principles underlying such mixing dynamics. They identified protocols that allow for the optimal mixing of the system when energetic costs or fluid motion are limiting factors. The paper is published in the journal Physical Review Letters.

“We found that the most effective stirring strategies share a universal structure and are symmetric in time,” says Luca Cocconi, first author of the study. “These optimal protocols reveal a fundamental limit on how efficiently information—for example about the identity and position of particles—can be erased in such systems.”