SUBSYSTEMS. “Their remarkable abundance ratios in comparison to a negligible one of ordinary matter suggests an extended thermodynamical viewpoint in which the evolution of material subsystems in the universe can be compared to the “heat engines” working between a couple of “heat reservoirs” with higher and lower temperature, which correspond respectively to the dark matter with positive energy and the negative dark energy.”
https://www.mdpi.com/2073-8994/12/8/1244/htm