Quantum mechanical Carnot engine

A cyclic thermodynamic heat engine runs most efficiently if it is reversibl e. Carnot constructed such a reversible heat engine by combining adiabatic and isothermal processes for a system containing an ideal gas. Here, we pre sent an example of a cyclic engine based on a single quantum mechanical par ticle confined to a potential well. The efficiency of this engine is shown to equal the Carnot efficiency because quantum dynamics is reversible. The quantum heat engine has a cycle consisting of adiabatic and isothermal quan tum processes that are close analogues of the corresponding classical proce sses.