Energy harvesting from anisotropic fluctuations

Area of Science:

• Thermodynamics
• Statistical Mechanics
• Nonlinear Dynamics

Background:

• The Brownian gyrator is a model heat engine with two degrees of freedom in an anisotropic temperature field.
• It exhibits a nonequilibrium steady-state probability current that generates torque.

Purpose of the Study:

• To explore coupling the gyrator's motion with periodic actuation for work extraction.
• To establish universal bounds on the efficiency and speed of work extraction protocols.

Main Methods:

• Analysis of path lengths in thermodynamic state manifolds using a Riemannian metric to quantify dissipative losses.
• Area integrals of work density to quantify extracted work.
• Derivation of an isoperimetric inequality.

Main Results:

• Path lengths correspond to dissipative losses; area integrals quantify extracted work.
• An isoperimetric inequality provides a universal bound on cyclic operating protocol efficiency.
• A bound on traversal speed is established, beyond which positive work extraction is impossible.

Conclusions:

• The study provides guiding principles for designing autonomous engines that extract work from anisotropic fluctuations.
• The findings offer insights into the fundamental limits of heat engine efficiency and operation speed.