The Hungry Daemon: Does an Energy-Harvesting Active Particle Have to Obey the Second Law of Thermodynamics?

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review report of the manuscript “The Hungry Daemon: An energy-harvesting active particle must obey the Second Law of Thermodynamics” submitted to Entropy

The paper discusses an ideal experiment in which an active particle harvests energy from the environment. Although such a system may be seen to operate as a Perpetual Motion Machine, the authors argue through a mechanical analysis that this is impossible. The methodology is sound and the results are effectively explained.

As a minor comment, the authors are requested of explaining if there is any conceptual difference in the terms “Daemon” vs. “Demon”.

Author Response

Comment 1: As a minor comment, the authors are requested of explaining if there is any conceptual difference in the terms “Daemon” vs. “Demon”.

Response 1: Thank you very much for your comment. We have clarified the difference between the two terms in the revised manuscript in lines 149-152:
"(The model is referred to as a ``daemon'' rather than a ``demon'' in order to avoid an implicit claim that the model is a Demon like Maxwell's; instead the name is in analogy with the small autonomous processes in Unix-family computer operating systems.)"

Reviewer 2 Report

Comments and Suggestions for Authors

The Review is available in a PDF file.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

See PDF file

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf