Micro heat engine violates Carnot limit, which sets cap on how much heat can be converted to useful work

https://phys.org/news/2023-11-micro-age-old-thermodynamic-puzzle.html

"maximum power at maximum efficiency... overcomes Carnot limit of theoretical efficiency... rapidly changing electric field to cycle the engine between two states. Under these conditions, they found that the waste heat dissipated drastically reduced, bringing the efficiency close to 95% of the limit specified by Carnot... heat distribution time reduced using electric field to move particle in colloidal medium enabling high efficiency and durability with large power output even while operating at high speeds"