Editorial

6 pages, 222 KiB

Open AccessEditorial

The Landauer Principle: Re-Formulation of the Second Thermodynamics Law or a Step to Great Unification?

by Edward Bormashenko

Entropy 2019, 21(10), 918; https://doi.org/10.3390/e21100918 - 20 Sep 2019

Cited by 22 | Viewed by 5294

The Landauer principle quantifies the thermodynamic cost of the recording/erasure of one bit of information, as it was stated by its author: “information is physical” and it has an energy equivalent. In its narrow sense, the Landauer principle states that the erasure of [...] Read more.

The Landauer principle quantifies the thermodynamic cost of the recording/erasure of one bit of information, as it was stated by its author: “information is physical” and it has an energy equivalent. In its narrow sense, the Landauer principle states that the erasure of one bit of information requires a minimum energy cost equal to k_BT ln2, where T is the temperature of a thermal reservoir used in the process and

k_{B}

is Boltzmann’s constant. The Landauer principle remains highly debatable. It has been argued that, since it is not independent of the second law of thermodynamics, it is either unnecessary or insufficient as an exorcism of Maxwell’s demon. On the other hand, the Landauer principle enables the “informational” reformulation of thermodynamic laws. Thus, the Landauer principle touches the deepest physical roots of thermodynamics. Authors are invited to contribute papers devoted to the meaning, interpretation, physical roots, experimental verification and applications of the Landauer principle. Papers devoted to the quantum and relativity aspects of the Landauer principle are encouraged. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

Research

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12 pages, 1886 KiB

Open AccessArticle

Survival of Virus Particles in Water Droplets: Hydrophobic Forces and Landauer’s Principle

by Edward Bormashenko, Alexander A. Fedorets, Leonid A. Dombrovsky and Michael Nosonovsky

Entropy 2021, 23(2), 181; https://doi.org/10.3390/e23020181 - 30 Jan 2021

Cited by 13 | Viewed by 3226

Abstract

Many small biological objects, such as viruses, survive in a water environment and cannot remain active in dry air without condensation of water vapor. From a physical point of view, these objects belong to the mesoscale, where small thermal fluctuations with the characteristic [...] Read more.

Many small biological objects, such as viruses, survive in a water environment and cannot remain active in dry air without condensation of water vapor. From a physical point of view, these objects belong to the mesoscale, where small thermal fluctuations with the characteristic kinetic energy of k_BT (where k_B is the Boltzmann’s constant and T is the absolute temperature) play a significant role. The self-assembly of viruses, including protein folding and the formation of a protein capsid and lipid bilayer membrane, is controlled by hydrophobic forces (i.e., the repulsing forces between hydrophobic particles and regions of molecules) in a water environment. Hydrophobic forces are entropic, and they are driven by a system’s tendency to attain the maximum disordered state. On the other hand, in information systems, entropic forces are responsible for erasing information, if the energy barrier between two states of a switch is on the order of k_BT, which is referred to as Landauer’s principle. We treated hydrophobic interactions responsible for the self-assembly of viruses as an information-processing mechanism. We further showed a similarity of these submicron-scale processes with the self-assembly in colloidal crystals, droplet clusters, and liquid marbles. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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10 pages, 1361 KiB

Open AccessArticle

What Is Temperature? Modern Outlook on the Concept of Temperature

by Edward Bormashenko

Entropy 2020, 22(12), 1366; https://doi.org/10.3390/e22121366 - 03 Dec 2020

Cited by 3 | Viewed by 4435

Abstract

The meaning and evolution of the notion of “temperature” (which is a key concept for the condensed and gaseous matter theories) are addressed from different points of view. The concept of temperature has turned out to be much more fundamental than conventionally thought. [...] Read more.

The meaning and evolution of the notion of “temperature” (which is a key concept for the condensed and gaseous matter theories) are addressed from different points of view. The concept of temperature has turned out to be much more fundamental than conventionally thought. In particular, the temperature may be introduced for systems built of a “small” number of particles and particles at rest. The Kelvin temperature scale may be introduced into quantum and relativistic physics due to the fact that the efficiency of the quantum and relativistic Carnot cycles coincides with that of the classical one. The relation of temperature with the metrics of the configurational space describing the behavior of systems built from non-interacting particles is demonstrated. The role of temperature in constituting inertia and gravity forces treated as entropy forces is addressed. The Landauer principle asserts that the temperature of a system is the only physical value defining the energy cost of the isothermal erasure of a single bit of information. The fundamental role of the temperature of the cosmic microwave background in modern cosmology is discussed. The range of problems and controversies related to the negative absolute temperature is treated. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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17 pages, 3575 KiB

Open AccessArticle

Observable and Unobservable Mechanical Motion

by J. Gerhard Müller

Entropy 2020, 22(7), 737; https://doi.org/10.3390/e22070737 - 03 Jul 2020

Cited by 1 | Viewed by 3369

Abstract

A thermodynamic approach to mechanical motion is presented, and it is shown that dissipation of energy is the key process through which mechanical motion becomes observable. By studying charged particles moving in conservative central force fields, it is shown that the process of [...] Read more.

A thermodynamic approach to mechanical motion is presented, and it is shown that dissipation of energy is the key process through which mechanical motion becomes observable. By studying charged particles moving in conservative central force fields, it is shown that the process of radiation emission can be treated as a frictional process that withdraws mechanical energy from the moving particles and that dissipates the radiation energy in the environment. When the dissipation occurs inside natural (eye) or technical photon detectors, detection events are produced which form observational images of the underlying mechanical motion. As the individual events, in which radiation is emitted and detected, represent pieces of physical action that add onto the physical action associated with the mechanical motion itself, observation appears as a physical overhead that is burdened onto the mechanical motion. We show that such overheads are minimized by particles following Hamilton’s equations of motion. In this way, trajectories with minimum curvature are selected and dissipative processes connected with their observation are minimized. The minimum action principles which lie at the heart of Hamilton’s equations of motion thereby appear as principles of minimum energy dissipation and/or minimum information gain. Whereas these principles dominate the motion of single macroscopic particles, these principles become challenged in microscopic and intensely interacting multi-particle systems such as molecules moving inside macroscopic volumes of gas. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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6 pages, 1240 KiB

Open AccessArticle

Informational Reinterpretation of the Mechanics Notions and Laws

by Edward Bormashenko

Entropy 2020, 22(6), 631; https://doi.org/10.3390/e22060631 - 07 Jun 2020

Cited by 5 | Viewed by 2587

Abstract

The informational re-interpretation of the basic laws of the mechanics exploiting the Landauer principle is suggested. When a physical body is in rest or it moves rectilinearly with the constant speed, zero information is transferred; thus, the informational affinity of the rest state [...] Read more.

The informational re-interpretation of the basic laws of the mechanics exploiting the Landauer principle is suggested. When a physical body is in rest or it moves rectilinearly with the constant speed, zero information is transferred; thus, the informational affinity of the rest state and the rectilinear motion with a constant speed is established. Inertial forces may be involved in the erasure/recording of information. The analysis of the minimal Szilard thermal engine as seen from the noninertial frame of references is carried out. The Szilard single-particle minimal thermal engine undergoes isobaric expansion relative to accelerated frame of references, enabling the erasure of 1 bit of information. The energy ΔQ spent by the inertial force for the erasure of 1 bit of information is estimated as

Δ Q ≅ \frac{5}{3} k_{B} \bar{T}

, which is larger than the Landauer bound but qualitatively is close to it. The informational interpretation of the equivalence principle is proposed: the informational content of the inertial and gravitational masses is the same. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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15 pages, 4014 KiB

Open AccessArticle

Photon Detection as a Process of Information Gain

by J Gerhard Müller

Entropy 2020, 22(4), 392; https://doi.org/10.3390/e22040392 - 30 Mar 2020

Cited by 4 | Viewed by 3638

Abstract

Making use of the equivalence between information and entropy, we have shown in a recent paper that particles moving with a kinetic energy

ε

carry potential information [...] Read more.

Making use of the equivalence between information and entropy, we have shown in a recent paper that particles moving with a kinetic energy

ε

carry potential information

i_{p o t} (ε, T) = \frac{1}{\ln (2)} \frac{ε}{k_{B} T}

relative to a heat reservoir of temperature

T

. In this paper we build on this result and consider in more detail the process of information gain in photon detection. Considering photons of energy

E_{p h}

and a photo-ionization detector operated at a temperature

T_{D}

, we evaluate the signal-to-noise ratio

S N (E_{p h}, T_{D})

for different detector designs and detector operation conditions and show that the information gain realized upon detection,

i_{r e a l} (E_{p h}, T_{D})

, always remains smaller than the potential information

i_{p o t} (E_{p h}, T_{D})

carried with the photons themselves, i.e.,:

i_{r e a l} (E_{p h}, T_{D}) = \frac{1}{\ln (2)} \ln (S N (E_{p h}, T_{D})) \leq i_{p o t} (E_{p h}, T_{D}) = \frac{1}{\ln (2)} \frac{E_{p h}}{k_{B} T_{D}}

. This result is shown to be generally valid for all kinds of technical photon detectors, which shows that

i_{p o t} (E_{p h}, T_{D})

can indeed be regarded as an intrinsic information content that is carried with the photons themselves. Overall, our results suggest that photon detectors perform as thermodynamic engines that incompletely convert potential information into realized information with an efficiency that is limited by the second law of thermodynamics and the Landauer energy bounds on information gain and information erasure. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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12 pages, 280 KiB

Open AccessArticle

Landauer Principle and General Relativity

by Luis Herrera

Entropy 2020, 22(3), 340; https://doi.org/10.3390/e22030340 - 16 Mar 2020

Cited by 16 | Viewed by 3769

Abstract

We endeavour to illustrate the physical relevance of the Landauer principle applying it to different important issues concerning the theory of gravitation. We shall first analyze, in the context of general relativity, the consequences derived from the fact, implied by Landauer principle, that [...] Read more.

We endeavour to illustrate the physical relevance of the Landauer principle applying it to different important issues concerning the theory of gravitation. We shall first analyze, in the context of general relativity, the consequences derived from the fact, implied by Landauer principle, that information has mass. Next, we shall analyze the role played by the Landauer principle in order to understand why different congruences of observers provide very different physical descriptions of the same space-time. Finally, we shall apply the Landauer principle to the problem of gravitational radiation. We shall see that the fact that gravitational radiation is an irreversible process entailing dissipation, is a straightforward consequence of the Landauer principle and of the fact that gravitational radiation conveys information. An expression measuring the part of radiated energy that corresponds to the radiated information and an expression defining the total number of bits erased in that process, shall be obtained, as well as an explicit expression linking the latter to the Bondi news function. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

18 pages, 2623 KiB

Open AccessFeature PaperArticle

Landauer’s Principle in a Quantum Szilard Engine without Maxwell’s Demon

by Alhun Aydin, Altug Sisman and Ronnie Kosloff

Entropy 2020, 22(3), 294; https://doi.org/10.3390/e22030294 - 03 Mar 2020

Cited by 19 | Viewed by 5215

Abstract

Quantum Szilard engine constitutes an adequate interplay of thermodynamics, information theory and quantum mechanics. Szilard engines are in general operated by a Maxwell’s Demon where Landauer’s principle resolves the apparent paradoxes. Here we propose a Szilard engine setup without featuring an explicit Maxwell’s [...] Read more.

Quantum Szilard engine constitutes an adequate interplay of thermodynamics, information theory and quantum mechanics. Szilard engines are in general operated by a Maxwell’s Demon where Landauer’s principle resolves the apparent paradoxes. Here we propose a Szilard engine setup without featuring an explicit Maxwell’s demon. In a demonless Szilard engine, the acquisition of which-side information is not required, but the erasure and related heat dissipation still take place implicitly. We explore a quantum Szilard engine considering quantum size effects. We see that insertion of the partition does not localize the particle to one side, instead creating a superposition state of the particle being in both sides. To be able to extract work from the system, particle has to be localized at one side. The localization occurs as a result of quantum measurement on the particle, which shows the importance of the measurement process regardless of whether one uses the acquired information or not. In accordance with Landauer’s principle, localization by quantum measurement corresponds to a logically irreversible operation and for this reason it must be accompanied by the corresponding heat dissipation. This shows the validity of Landauer’s principle even in quantum Szilard engines without Maxwell’s demon. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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6 pages, 1076 KiB

Open AccessArticle

Generalization of the Landauer Principle for Computing Devices Based on Many-Valued Logic

by Edward Bormashenko

Entropy 2019, 21(12), 1150; https://doi.org/10.3390/e21121150 - 25 Nov 2019

Cited by 10 | Viewed by 3326

Abstract

The Landauer principle asserts that “the information is physical”. In its strict meaning, Landauer’s principle states that there is a minimum possible amount of energy required to erase one bit of information, known as the Landauer bound [...] Read more.

The Landauer principle asserts that “the information is physical”. In its strict meaning, Landauer’s principle states that there is a minimum possible amount of energy required to erase one bit of information, known as the Landauer bound

W = k_{B} T l n 2

, where T is the temperature of a thermal reservoir used in the process and

k_{B}

is Boltzmann’s constant. Modern computers use the binary system in which a number is expressed in the base-2 numeral system. We demonstrate that the Landauer principle remains valid for the physical computing device based on the ternary, and more generally, N-based logic. The energy necessary for erasure of one bit of information (the Landauer bound)

W = k_{B} T l n 2

remains untouched for the computing devices exploiting a many-valued logic. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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13 pages, 3706 KiB

Open AccessArticle

Information Contained in Molecular Motion

by J Gerhard Müller

Entropy 2019, 21(11), 1052; https://doi.org/10.3390/e21111052 - 28 Oct 2019

Cited by 9 | Viewed by 5997

Abstract

The equivalence between information and entropy is used to interpret the entropy of a molecular gas as missing information about its internal state of motion. Our considerations show that thermodynamic information is principally composed of two parts which continually change in the course [...] Read more.

The equivalence between information and entropy is used to interpret the entropy of a molecular gas as missing information about its internal state of motion. Our considerations show that thermodynamic information is principally composed of two parts which continually change in the course of gas-kinetic collisions. While the first part relates to energy carried by the individual molecules in the form of kinetic energy and in internal excitations, the second relates to information concerned with the location of the molecules within their own mean-free volumes. It is shown that this second kind of information is generated in gas-kinetic collisions and rapidly deteriorated and lost by quantum mechanical dispersion until it is re-gained in follow-on collisions. It is proposed that gas-kinetic collisions can be regarded as measurement processes in which information is continually gained, deteriorated and erased. As these processes occur naturally without any human intervention, it is argued that thermodynamic information—like entropy—fully qualifies as an objective physical quantity. Full article

(This article belongs to the Special Issue The Landauer Principle: Meaning, Physical Roots and Applications)

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