Harnessing Nonequilibrium Dynamics: Toward an Odd Engine in Marine Active Matter

Abstract

Active matter consists of interacting components that continuously consume energy and operate far from equilibrium, giving rise to emergent structures and symmetry-breaking dynamics across scales. A central challenge is to understand how microscopic energy injection and symmetry breaking can be harnessed to perform useful work at the macroscopic level. In this thesis, I approach this question through the lens of building an “odd engine”—a system that exploits broken time-reversal and chiral symmetries to produce work-generating cycles in marine active matter. Using marine organisms as model systems of active matter—including starfish oocytes, starfish embryos, and sea urchin embryos—I develop experimental strategies to control and probe nonequilibrium dynamics through biochemical and mechanical perturbations. I further demonstrate that by characterizing the key broken symmetries, one can reveal the underlying physical principles that enable energy transduction across scales for collective dynamics. In Chapter 2, I experimentally titrate metabolic activity to control the oscillatory dynamics of mechanochemical patterns on the membrane of starfish oocytes. I then show that one can estimate the dissipation timescale as well as a lower bound on the entropy production rate by quantifying time-reversal asymmetry of observed time series. This establishes a route to characterize the energetic “fuel” driving active processes. In Chapter 3, I show that two chiral symmetry–breaking mechanisms of starfish embryos lead to two stable dynamical states—the fluctuating and oscillatory states—in living chiral crystals. I further demonstrate that one can controllably excite the oscillatory dynamics, as well as tune the properties of work-generating cycles, using bulk mechanical perturbations. These results constitute a minimal realization of an odd engine in living matter. In Chapter 4, I show that chiral self-propulsion dynamics of sea urchin embryos lead to edge currents and surface waves at the boundary of living chiral fluids. Employing local mechanical perturbations by embedded microrobots, I observe a nonzero Hall angle as a signature of odd viscosity. This provides a mechanism to integrate synthetic components that can guide and potentially extract collective motion from living systems. Together, these results establish design principles for harnessing nonequilibrium dynamics in living systems and outline a pathway toward engineering odd engines and active metamaterials that autonomously convert microscopic activity into macroscopic function.