(443i) Odd Transport in Active Matter

Linear constitutive relations are foundational to the study of transport phenomena. Such relations connect fluxes (e.g. of mass, momentum, or heat) to thermodynamic driving forces through tensors of transport coefficients. The properties of these tensors reflect the underlying microscopic dynamics, as addressed within the framework of non-equilibrium thermodynamics.

Though usually neglected, transport coefficient tensors may contain antisymmetric components driving fluxes perpendicular to conjugate thermodynamic forces. In this talk, we describe how such antisymmetric (or “odd”) transport can arise at the continuum level as a consequence of breaking time-reversal and parity symmetries in the microscopic dynamics. This possibility is motivated in particular by the study of active systems, which are driven by non-conservative forces and thus inherently out of equilibrium. We show that odd transport coefficients emerge due to breaking time-reversal and parity symmetries as can be understood through deriving Green-Kubo relations, which additionally provide an avenue for direct numerical verification in model active matter systems using molecular dynamics simulations. Our work provides steps towards extending the framework of non-equilibrium thermodynamics to systems like active matter, which are inherently out of equilibrium, or for which no equilibrium reference state exists.