Performance of a Brownian information engine through potential profiling: Optimum output requisites, Heating-to-Refrigeration transition and their Re-entrance

Abstract: Brownian Information engine (BIE) harnesses the energy from a fluctuating environment by utilizing the associated information change in the presence of a single heat bath. The engine operates in a space-dependent confining potential and requires an appropriate feedback control mechanism. In general, the feedback controller has three different steps: measurement, feedback, and relaxation. The feedback step is related to a sudden change in the potential energy that is essential for a nonzero work output. BIE utilises the amount of information (surprise) acquired during the measurement step for the energy output. However, due to the relaxation process, a certain amount of acquired information is lost or becomes unavailable. So, controlling information loss during relaxation is crucial for the overall efficiency of the engine. The net (available) information, therefore, can be monitored by tuning the feedback controller and the shape of the confining potential. In this paper, we explore the effect of the shape modulation of the confining potential, which may have multiple stable valleys and unstable hills, on the net available information and, hence, the performance of a BIE that operates under an asymmetric feedback protocol. We examine the optimal performance requirements of the BIE and the amount of maximum work output under different potential profiling. For monostable trapping, a concave shape in confining potential results in a higher work output than a convex one. We also find that hills and valleys in the confining potential may lead to multiple good operating conditions. An appropriate shape modulation can create a heater-refrigerator transition and their reentrance due to non-trivial changes in information loss during the relaxation process.