ABSTRACT: Born in the age of steam, classical thermodynamics set fundamental limits on efficiency for idealized, quasi-static cycles. But real engines operate in finite time and far from equilibrium, where the central question is often not efficiency but how much power can be produced—and, until recently, there were no comparable first-principles bounds on power grounded in an explicit statistical-mechanical stochastic model. Thermal fluctuations can be biased in nonequilibrium settings—for example, when noise differs by direction or by degree of freedom (“thermal anisotropy”). Can such anisotropy be turned into useful work, and what ultimately limits the power that can be generated? In the talk we will present a stochastic-thermodynamic approach, building on recent links between stochastic control and thermodynamics, that describes a mesoscopic engine through the evolving probability distribution of its internal states. Within this framework we derive explicit upper bounds on the maximum power obtainable from anisotropic thermal driving, with implications for engineered and natural systems. We will close with a minimal gyrating autonomous-engine model that continuously converts a thermal bias into steady rotation and power output.

The talk is based on joint works with Olga Movilla (UCI), Amir Taghvaei (UW) and Yongxin Chen (GaTech). Research funding by AFOSR, ARO and NSF is gratefully acknowledged.

BIOSKETCH: Tryphon T. Georgiou is a Distinguished Professor in the Department of Mechanical and Aerospace Engineering at the University of California, Irvine, and a Professor Emeritus at the University of Minnesota, Minneapolis. Georgiou joined the faculty of the University of California, Irvine in 2016 after almost thirty years at the University of Minnesota, where he held the Vincentine Hermes-Luh Chair (2002-2016) and served as a co-director of the Center for Control Science and Dynamical Systems (1990-2016). He was educated at the National Technical University of Athens, Greece (1979) and the University of Florida, Gainesville (PhD. 1983). Professor Georgiou is a Fellow of the IEEE, SIAM, IFAC, the American Association for the Advancement of Science (AAAS), and a Foreign Member of the Royal Swedish Academy of Engineering Sciences (IVA).