From Thermodynamics to Information: Landauer’s Limit and Negentropy Principle Applied to Magnetic Skyrmions

Roberto Zivieri

doi:10.3389/fphy.2022.769904

Abstract

Magnetic skyrmions are topological swirling spin textures objects that can be manipulated and employed as information carriers. This is accomplished based either on their ground-state properties or their thermodynamic properties. Landauer’s principle establishes an irreversible conversion from information to physics. The inverse mechanism, the inverse mechanism is proposed for magnetic topological defects forming in magnetic nanostructures that are regarded as closed thermodynamic systems confirming Szilard’s and Brillouin’s hypotheses. This mechanism consists of the creation of bits of information using a thermodynamic source having a form of negentropy. In this perspective article, the following are proved for magnetic skyrmions: 1) Landauer’s principle expressed in terms of negentropy and 2) the generalized second principle of thermodynamics based on Brillouin’s negentropy principle of information. The thermodynamic entropy is converted into information entropy at the expense of negentropy, “negative entropy” corresponding to the loss of thermodynamic entropy from the magnetic skyrmion itself. A recently proposed practical device enables the verification of points 1) and 2) and allows a full understanding of the interchange between thermodynamics and information and vice versa regarding skyrmions as information units and showing, in perspective, the considerable advantages offered by this type of storing and coding information.

Highlights

Magnetic skyrmions are axisymmetric topological solitons of vortex-like character hosted in ferromagnetic materials
Great efforts have been devoted to the manipulation of magnetic skyrmions forming in magnetic nanostructures based on their ground-state magnetic properties and giving rise to spintronic applications [1,2,3,4]
In a data communication system, it is crucial to understand how the information from the sender allows an amount of negentropy N to get converted into information entropy HI. This occurs because the sender sends to the magnetic skyrmion a binary input of amplitude 2n where n is the number of bits of information entropy

Summary

INTRODUCTION

Magnetic skyrmions are axisymmetric topological solitons of vortex-like character hosted in ferromagnetic materials. This occurs because the sender sends to the magnetic skyrmion a binary input of amplitude 2n where n is the number of bits of information entropy This binary input might be regarded in a way similar to a light input interacting with matter (e.g., a laser source), and this interaction with the skyrmion allows rewriting its thermodynamic configuration and its corresponding entropy. The receiver consists of a binary sensor made by binary inputs enabling to read the discrete signal corresponding to a sequence of binary configurations assigned to a given entropy density This coding has the considerable advantage to potentially create more bits for an equal number of skyrmions.

CONCLUSION

DATA AVAILABILITY STATEMENT