Demon Dynamics:
Deterministic Chaos, the Szilard Map, and
the Intelligence of Thermodynamic Systems

Alexander B. Boyd and James P. Crutchfield

Complexity Sciences Center
Physics Department
University of California at Davis
Davis, CA 95616

ABSTRACT: We introduce a deterministic chaotic system—the Szilard Map—that encapsulates the measurement, control, and erasure protocol by which Maxwellian Demons extract work from a heat reservoir. Implementing the Demon's control function in a dynamical embodiment, our construction symmetrizes Demon and thermodynamic system, allowing one to explore their functionality and recover the fundamental trade-off between the thermodynamic costs of dissipation due to measurement and due to erasure. The map's degree of chaos—captured by the Kolmogorov-Sinai entropy—is the rate of energy extraction from the heat bath. Moreover, an engine's statistical complexity quantifies the minimum necessary system memory for it to function. In this way, dynamical instability in the control protocol plays an essential and constructive role in intelligent thermodynamic systems.

Selected animations of continuous-time embedding of the Szilard Map:
Demon reset mesostate A (MPEG 4)
Demon reset mesostate B (MPEG 4)


Alexander B. Boyd and James P. Crutchfield, "Demon Dynamics: Deterministic Chaos, the Szilard Map, and the Intelligence of Thermodynamic Systems", (2015) submitted.
doi:XXX.
[pdf] 500 KB
Santa Fe Institute Working Paper 15-06-019.
arxiv.org:1506.04327 [cond-mat.stat-mech].