Related Experiment Video
Updated: Apr 10, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Comment on "Similarity between quantum mechanics and thermodynamics: Entropy, temperature, and Carnot cycle"
L A González-Díaz1, S Díaz-Solórzano2
1Laboratorio de Dinámica No Lineal y Sistemas Complejos, Centro de Física, Instituto Venezolano de Investigaciones Científicas, Caracas 1020-A, Venezuela.
Abstract:
In the paper by Abe and Okuyama [Phys. Rev. E 83, 021121 (2011)], the quantum Carnot cycle of a simple two-state model of a particle confined in a one-dimensional infinite potential well is discussed. It is claimed that the state at the beginning of the quantum Carnot cycle is pure. After that, it is apparently transmuted to a mixed state if Clausius equality is imposed. We prove that this statement is incorrect. In particular, we prove that the state at the beginning of the cycle is mixed due to the process of measuring energy.
More Related Videos
Related Concept Videos
The Entropy as a State Function
Entropy and the Second Law of Thermodynamics
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...
Entropy and the Second Law of Thermodynamics
Entropy
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
Entropy
Second Law of Thermodynamics

