Szilard Engine — Maxwell's Demon

Information as thermodynamic resource: Landauer's principle in action
Cycle steps:
Ready
Press a step or Auto to run the Szilard engine cycle.
Work extracted: 0 k_BT
Demon memory: empty
0
Total W (k_BT)
0
Cycles
0%
Efficiency

Landauer's Principle

The Szilard engine (1929) extracts k_BT ln 2 of work per cycle using a single molecule and a demon who measures which side it occupies. This seems to violate the second law — but Landauer (1961) showed: erasing 1 bit of memory costs at least k_BT ln 2 of heat.

Bennett (1982) confirmed: the measurement is reversible; the erasure step is irreversible. Information has a physical cost. The total entropy production per cycle is exactly zero when accounting for demon's memory.

Maxwell's demon Landauer principle information thermodynamics Bennett 1982