The Physics of Maxwell's demon and information

In mathematical physical analyses of Szilard's engine and Maxwell's demon, a general assumption (explicit or implicit) is that one can neglect the energy needed for relocating the piston in Szilard's engine and for driving the trap door in Maxwell's demon. If this basic assumption is wrong, then the conclusions of a vast literature on the implications of the Second Law of Thermodynamics and of Landauer's erasure theorem are incorrect too. Our analyses of the fundamental infor...

In this paper we examine the Maxwell Demon problem from an information theoretic and computational point-of-view. In particular we calculate the required capacity of a communication channel that transports information to and from the Demon. Equivalently, this is the number of bits required to store the information on a computer tape. We show that, in a simple model for the Maxwell Demon, the entropy of the universe increases by at least an amount eta=0.83999552 bits per parti...

In this highly speculative Letter it is argued that, under certain physical conditions, Maxwell's demon might be capable of breaking the second law of thermodynamics, thereby allowing a perpetual motion machine of the second kind, by accessing single particle capabilities.

Szilard's one-molecule engine is operated by a Maxwell's demon attempting to convert heat to work. It is argued here that when using the demon to relate information to work (Landauer's principle), the demon's goal must be regarded as an implicit assumption that should not be taken for granted. Other demons than the standard one can be constructed depending on their assumed goal. When the demon is purely mechanical, the goal is instilled in it by its design. When the demon is ...

In his famous letter in 1870, Maxwell describes how Joule's law can be violated "only by the intelligent action of a mere guiding agent", later coined as Maxwell's demon by Lord Kelvin. In this letter we study thermodynamics of information using an experimentally feasible Maxwell's demon setup based a single electron transistor capacitively coupled to a single electron box, where both the system and the Demon can be clearly identified. Such an engineered on-chip Demon measure...

This paper discusses Maxwell's demon thought experiment. In recent years, there has been extensive research on Maxwell's demon. I first provide a detailed overview of important historical milestones of Maxwell's demon thought experiment. Einstein would often write about both relativity and thermodynamics. In this paper, I first argue that: 1. Einstein spoke of Perpetuum mobile of the second kind (a Maxwell's demon) in the context of the discovery of his relativity theory, the...

In apparent contradiction to the laws of thermodynamics, Maxwell's demon is able to cyclically extract work from a system in contact with a thermal bath exploiting the information about its microstate. The resolution of this paradox required the insight that an intimate relationship exists between information and thermodynamics. Here, we realize a Maxwell demon experiment that tracks the state of each constituent both in the classical and quantum regimes. The demon is a micro...

Maxwell demons are creatures that are imagined to be able to reduce the entropy of a system without performing any work on it. Conventionally, such a Maxwell demon's intricate action consists of measuring individual particles and subsequently performing feedback. Here we show that much simpler setups can still act as demons: we demonstrate that it is sufficient to exploit a non-equilibrium distribution to seemingly break the second law of thermodynamics. We propose both an el...

A CMOS-based implementation of an autonomous Maxwell's demon was recently proposed (Phys. Rev. Lett. 129, 120602) to demonstrate that a Maxwell demon can still work at macroscopic scales, provided that its power supply is scaled appropriately. Here, we first provide a full analytical characterization of the non-autonomous version of that model. We then study system-demon information flows within generic autonomous bipartite setups displaying a macroscopic limit. By doing so, ...

We report an experimental realisation of Maxwell's demon in a photonic setup. We show that a measurement at the single-photon level followed by a feed-forward operation allows the extraction of work from intense thermal light into an electric circuit. The interpretation of the experiment stimulates the derivation of a new equality relating work extraction to information acquired by measurement. We derive a bound using this relation and show that it is in agreement with the ex...