B. Tyukodi, Armand Barbot, Reinaldo Garci'a-Garci'a, Matthias Lerbinger, S. Patinet, D. Vandembroucq
The coarse-graining of amorphous plasticity from the atomistic to the mesoscopic scale is studied in the framework of a simple scalar elasto-plastic model. Building on recent results obtained on the atomistic scale, we discuss the interest in a disordered landscape-informed threshold disorder to reproduce the physics of amorphous plasticity. We show that accounting for a rejuvenation scenario allows us to reproduce quasi-quantitatively the evolution of the mean local yield stress and the localization behavior. We emphasize the crucial role of two dimensionless parameters: the relative strength of the yield stress disorder with respect to the typical stress drops associated with a plastic rearrangement, and the age parameter characterizing the relative stability of the initial glass with respect to the rejuvenated glass that emerges upon shear deformation.
{"title":"Coarse-graining amorphous plasticity: impact of rejuvenation and disorder","authors":"B. Tyukodi, Armand Barbot, Reinaldo Garci'a-Garci'a, Matthias Lerbinger, S. Patinet, D. Vandembroucq","doi":"10.5802/crphys.156","DOIUrl":"https://doi.org/10.5802/crphys.156","url":null,"abstract":"The coarse-graining of amorphous plasticity from the atomistic to the mesoscopic scale is studied in the framework of a simple scalar elasto-plastic model. Building on recent results obtained on the atomistic scale, we discuss the interest in a disordered landscape-informed threshold disorder to reproduce the physics of amorphous plasticity. We show that accounting for a rejuvenation scenario allows us to reproduce quasi-quantitatively the evolution of the mean local yield stress and the localization behavior. We emphasize the crucial role of two dimensionless parameters: the relative strength of the yield stress disorder with respect to the typical stress drops associated with a plastic rearrangement, and the age parameter characterizing the relative stability of the initial glass with respect to the rejuvenated glass that emerges upon shear deformation.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48462225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Random First Order Transition (RFOT) theory started with the pioneering work of Kirkpatrick, Thirumalai and Wolynes. It leverages the methods and advances of the theory of disordered systems. It fares remarkably well at reproducing the salient experimental facts of super-cooled liquids. Yet, direct and indisputable experimental validations are missing. In this short survey, we will review recent investigations that broadly support all static aspects of RFOT, but also those for which the standard dynamical extension of the theory appears to be struggling, in particular in relation with facilitation effects. We discuss possible solutions and open issues.
{"title":"The RFOT Theory of Glasses: Recent Progress and Open Issues","authors":"G. Biroli, J. Bouchaud","doi":"10.5802/crphys.136","DOIUrl":"https://doi.org/10.5802/crphys.136","url":null,"abstract":"The Random First Order Transition (RFOT) theory started with the pioneering work of Kirkpatrick, Thirumalai and Wolynes. It leverages the methods and advances of the theory of disordered systems. It fares remarkably well at reproducing the salient experimental facts of super-cooled liquids. Yet, direct and indisputable experimental validations are missing. In this short survey, we will review recent investigations that broadly support all static aspects of RFOT, but also those for which the standard dynamical extension of the theory appears to be struggling, in particular in relation with facilitation effects. We discuss possible solutions and open issues.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43853961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the breathing (monopole) oscillations and their damping in a harmonically trapped one-dimensional (1D) Bose gas in the quasicondensate regime using a finite-temperature classical field approach. By characterising the oscillations via the dynamics of the density profile's rms width over long time, we find that the rms width displays beating of two distinct frequencies. This means that 1D Bose gas oscillates not at a single breathing mode frequency, as found in previous studies, but as a superposition of two distinct breathing modes, one oscillating at frequency close to $simeq!sqrt{3}omega$ and the other at $simeq!2omega$, where $omega$ is the trap frequency. The breathing mode at $sim!sqrt{3}omega$ dominates the beating at lower temperatures, deep in the quasicondensate regime, and can be attributed to the oscillations of the bulk of the density distribution comprised of particles populating low-energy, highly-occupied states. The breathing mode at $simeq!2omega$, on the other hand, dominates the beating at higher temperatures, close to the nearly ideal, degenerate Bose gas regime, and is attributed to the oscillations of the tails of the density distribution comprised of thermal particles in higher energy states. The two breathing modes have distinct damping rates, with the damping rate of the bulk component being approximately four times larger than that of the tails component.
{"title":"Frequency beating and damping of breathing oscillations of a harmonically trapped one-dimensional quasicondensate","authors":"F. A. Bayocboc, Jr., K. Kheruntsyan","doi":"10.5802/crphys.131","DOIUrl":"https://doi.org/10.5802/crphys.131","url":null,"abstract":"We study the breathing (monopole) oscillations and their damping in a harmonically trapped one-dimensional (1D) Bose gas in the quasicondensate regime using a finite-temperature classical field approach. By characterising the oscillations via the dynamics of the density profile's rms width over long time, we find that the rms width displays beating of two distinct frequencies. This means that 1D Bose gas oscillates not at a single breathing mode frequency, as found in previous studies, but as a superposition of two distinct breathing modes, one oscillating at frequency close to $simeq!sqrt{3}omega$ and the other at $simeq!2omega$, where $omega$ is the trap frequency. The breathing mode at $sim!sqrt{3}omega$ dominates the beating at lower temperatures, deep in the quasicondensate regime, and can be attributed to the oscillations of the bulk of the density distribution comprised of particles populating low-energy, highly-occupied states. The breathing mode at $simeq!2omega$, on the other hand, dominates the beating at higher temperatures, close to the nearly ideal, degenerate Bose gas regime, and is attributed to the oscillations of the tails of the density distribution comprised of thermal particles in higher energy states. The two breathing modes have distinct damping rates, with the damping rate of the bulk component being approximately four times larger than that of the tails component.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42245826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. Stellaroccultationsandtransitsoccurwhenaplanetarybodypassesinfrontofastar(includingour Sun). For objects with an atmosphere, refraction plays an essential role to explain the drops of flux and the aureoles observed during these events. This can be used to derived key parameters of the atmospheres, such as their density, pressure and temperature profiles, as well as the presence of atmospheric gravity waves and zonal winds. Here we derive from basic principles the equations that rule the ray propagation in planetary atmospheres, and we show how they can be used to derive the physical parameters of these atmospheres. Les occultations stellaires et les transits se produisent lorsqu’un corps planétaire passe devant une étoile (y comprisnotreSoleil).Pourlesobjetsavecuneatmosphère,lerôledelaréfractionestessentielpourexpliquer les chutes de flux et les auréoles observées lors de ces événements. Ces derniers peuvent être utilisés pour déduire des paramètres clés des atmosphères, comme leurs profils de densité, de pression et de température, ainsi que la présence d’ondes de gravité ou de vents zonaux. A partir des principes fondamentaux, nous déduisons les équations qui régissent la propagation des rayons dans les atmosphères planétaires, et nous montrons comment elles peuvent être utilisées pour déduire les paramètres physiques de ces atmosphères.
{"title":"Study of atmospheres in the solar system, from stellar occultation or planetary transit","authors":"B. Sicardy","doi":"10.5802/crphys.109","DOIUrl":"https://doi.org/10.5802/crphys.109","url":null,"abstract":". Stellaroccultationsandtransitsoccurwhenaplanetarybodypassesinfrontofastar(includingour Sun). For objects with an atmosphere, refraction plays an essential role to explain the drops of flux and the aureoles observed during these events. This can be used to derived key parameters of the atmospheres, such as their density, pressure and temperature profiles, as well as the presence of atmospheric gravity waves and zonal winds. Here we derive from basic principles the equations that rule the ray propagation in planetary atmospheres, and we show how they can be used to derive the physical parameters of these atmospheres. Les occultations stellaires et les transits se produisent lorsqu’un corps planétaire passe devant une étoile (y comprisnotreSoleil).Pourlesobjetsavecuneatmosphère,lerôledelaréfractionestessentielpourexpliquer les chutes de flux et les auréoles observées lors de ces événements. Ces derniers peuvent être utilisés pour déduire des paramètres clés des atmosphères, comme leurs profils de densité, de pression et de température, ainsi que la présence d’ondes de gravité ou de vents zonaux. A partir des principes fondamentaux, nous déduisons les équations qui régissent la propagation des rayons dans les atmosphères planétaires, et nous montrons comment elles peuvent être utilisées pour déduire les paramètres physiques de ces atmosphères.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46191171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We provide an overview of the different types of computational techniques developed over the years to study supercooled liquids, glassy materials and the physics of the glass transition. We organise these numerical strategies into four broad families. For each of them, we describe the general ideas without discussing any technical details. We summarise the type of questions which can be addressed by any given approach and outline the main results which have been obtained. Finally we describe two important directions for future computational studies of glassy systems.
{"title":"Computer simulations of the glass transition and glassy materials","authors":"J. Barrat, L. Berthier","doi":"10.5802/crphys.129","DOIUrl":"https://doi.org/10.5802/crphys.129","url":null,"abstract":"We provide an overview of the different types of computational techniques developed over the years to study supercooled liquids, glassy materials and the physics of the glass transition. We organise these numerical strategies into four broad families. For each of them, we describe the general ideas without discussing any technical details. We summarise the type of questions which can be addressed by any given approach and outline the main results which have been obtained. Finally we describe two important directions for future computational studies of glassy systems.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46284680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
jvillain@infonie.fr This special issue of Comptes Rendus Physique brings together articles by three winners of prizes awarded by the Academy of Sciences in 2020. The goal of this foreword is to make them more accessible by non experts, especially students. The first article, by Philippe Bourges (“Science et innovation” CEA prize), Dalila Bounoua and Yvan Sidis, is part of the history of superconductivity, fertile in unexpected twists for 110 years. It was in 1911 that the Dutch scientist Kamerlingh Onnes, having succeeded in achieving very low temperatures which allowed him to liquefy helium, had the very natural curiosity to study the properties of various elements at these temperatures. He was surprised to find that some of them had zero electrical resistance. An electric current could thus circulate for days in a ring of mercury. What was the explanation for this perpetual motion? It was not found until 46 years later by Bardeen, Cooper and Schrie ff er, in 1957. These three scientists showed that electrons can form pairs (Cooper pairs). In a simplified description, we can say that these pairs are bosons and that at very low temperatures these bosons undergo Bose condensation, which leads to superconductivity. It is obvious that a vanishing electric resistance has a considerable technological interest, but this interest was considerably reduced by the need for very low temperatures. The critical temperature of the elements culminates at about ten kelvins in niobium and can reach higher values in compounds, but it was not expected to exceed the 23 K which correspond to Nb 3 Ge. However, in 1986 in Zürich, Müller and Bednorz discovered a family of superconductors whose critical temperature was higher, and a little later exceeded the temperature of liquid
{"title":"Foreword: Prizes of the French Academy of Sciences 2020","authors":"Jacques Villain","doi":"10.5802/crphys.107","DOIUrl":"https://doi.org/10.5802/crphys.107","url":null,"abstract":"jvillain@infonie.fr This special issue of Comptes Rendus Physique brings together articles by three winners of prizes awarded by the Academy of Sciences in 2020. The goal of this foreword is to make them more accessible by non experts, especially students. The first article, by Philippe Bourges (“Science et innovation” CEA prize), Dalila Bounoua and Yvan Sidis, is part of the history of superconductivity, fertile in unexpected twists for 110 years. It was in 1911 that the Dutch scientist Kamerlingh Onnes, having succeeded in achieving very low temperatures which allowed him to liquefy helium, had the very natural curiosity to study the properties of various elements at these temperatures. He was surprised to find that some of them had zero electrical resistance. An electric current could thus circulate for days in a ring of mercury. What was the explanation for this perpetual motion? It was not found until 46 years later by Bardeen, Cooper and Schrie ff er, in 1957. These three scientists showed that electrons can form pairs (Cooper pairs). In a simplified description, we can say that these pairs are bosons and that at very low temperatures these bosons undergo Bose condensation, which leads to superconductivity. It is obvious that a vanishing electric resistance has a considerable technological interest, but this interest was considerably reduced by the need for very low temperatures. The critical temperature of the elements culminates at about ten kelvins in niobium and can reach higher values in compounds, but it was not expected to exceed the 23 K which correspond to Nb 3 Ge. However, in 1986 in Zürich, Müller and Bednorz discovered a family of superconductors whose critical temperature was higher, and a little later exceeded the temperature of liquid","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42254323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Parcours, pratique théorique et documents scientifiques « privés » du physicien Jacques Solomon","authors":"Martha-Cecilia Bustamante De La Ossa","doi":"10.5802/crphys.105","DOIUrl":"https://doi.org/10.5802/crphys.105","url":null,"abstract":"","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43106815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A thermal gradient generates an electric field in any solid hosting mobile electrons. In presence of a finite magnetic field (or Berry curvature) this electric field has a transverse component. These are known as Seebeck and Nernst coefficients. As Callen argued, back in 1948, the Seebeck effect quantifies the entropy carried by a flow of charged particles in absence of thermal gradient. Similarly, the Nernst conductivity, αx y , quantifies the entropy carried by a flow of magnetic flux in absence of thermal gradient. The present paper summarizes a picture in which the rough amplitude of the thermoelectric response is given by fundamental units and material-dependent length scales. Therefore, knowledge of material-dependent length scales allows predicting the amplitude of the signal measured by experiments. Specifically, the Nernst conductivity scales with the square of the mean-free-path in metals. Its anomalous component in magnets scales with the square of the fictitious magnetic length. Ephemeral Cooper pairs in the normal state of a superconductor generate a signal, which scales with the square of the superconducting coherence length and smoothly evolves to the signal produced by mobile vortices below the critical temperature. This article is a draft (not yet accepted!)
{"title":"Corrigendum: What is measured when measuring a thermoelectric coefficient?","authors":"Kamran Behnia","doi":"10.5802/crphys.100","DOIUrl":"https://doi.org/10.5802/crphys.100","url":null,"abstract":"A thermal gradient generates an electric field in any solid hosting mobile electrons. In presence of a finite magnetic field (or Berry curvature) this electric field has a transverse component. These are known as Seebeck and Nernst coefficients. As Callen argued, back in 1948, the Seebeck effect quantifies the entropy carried by a flow of charged particles in absence of thermal gradient. Similarly, the Nernst conductivity, αx y , quantifies the entropy carried by a flow of magnetic flux in absence of thermal gradient. The present paper summarizes a picture in which the rough amplitude of the thermoelectric response is given by fundamental units and material-dependent length scales. Therefore, knowledge of material-dependent length scales allows predicting the amplitude of the signal measured by experiments. Specifically, the Nernst conductivity scales with the square of the mean-free-path in metals. Its anomalous component in magnets scales with the square of the fictitious magnetic length. Ephemeral Cooper pairs in the normal state of a superconductor generate a signal, which scales with the square of the superconducting coherence length and smoothly evolves to the signal produced by mobile vortices below the critical temperature. This article is a draft (not yet accepted!)","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42774205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is currently a growing interest in the development of communication systems that consume as little energy as possible, with the idea of eliminating the presence of batteries, which are a very polluting component. This is why the principles of communication based on backscatter modulation, or even more simply on backscattering by a device that takes the form of a label, like a barcode, are being studied more and more. In the latter case, the idea is to use the radar signature of this totally passive label, the geometry of the elements printed on it having been specially designed to perform the desired functions. These new systems cannot claim to do the same things as those working with a power supply or a chip, but they may be of interest for certain applications where the reading distances do not exceed one metre. Compared to barcodes, the main advantages are related to the use of RF waves to communicate, which makes it possible to read through certain objects that are opaque to light, or to significantly reduce the acquisition time of identifiers by being able to scan larger reading areas more easily. Résumé. Il existe actuellement un intérêt croissant pour le développement de systèmes de communication consommant le moins d’énergie possible, avec l’idée d’éliminer la présence de batteries, qui sont des composants très polluants. C’est pourquoi on étudie de plus en plus les principes de communication RF basés sur la retro-modulation, ou même plus simplement sur la rétrodiffusion d’une onde par un dispositif qui prend la forme d’une étiquette, comme un code-barres. Dans ce dernier cas, il s’agit d’utiliser la signature radar de cette étiquette totalement passive ; la géométrie des éléments imprimés sur celle-ci ayant été spécialement conçue pour remplir les fonctions souhaitées. Ces nouveaux systèmes ne peuvent prétendre faire les mêmes choses que ceux fonctionnant avec une alimentation ou une puce, mais ils peuvent être intéressants pour certaines applications où les distances de lecture ne dépassent pas un mètre. Par rapport aux code-barres, les principaux avantages sont liés à l’utilisation des ondes RF pour communiquer, ce qui permet de lire à travers certains objets opaques à la lumière ou encore de réduire significativement le temps d’acquisition des identifiants en pouvant balayer plus facilement de plus grandes zones de lecture.
目前，人们对开发尽可能少消耗能源的通信系统越来越感兴趣，其想法是消除电池的存在，电池是一个非常污染的组成部分。这就是为什么基于后向散射调制的通信原理，或者更简单地说，通过采用标签形式的设备(如条形码)进行后向散射的通信原理正在得到越来越多的研究。在后一种情况下，我们的想法是使用这种完全被动标签的雷达特征，其上印刷的元素的几何形状经过专门设计以执行所需的功能。这些新系统不能声称与那些使用电源或芯片工作的系统做同样的事情，但它们可能对某些读取距离不超过一米的应用感兴趣。与条形码相比，其主要优点与使用射频波进行通信有关，这使得通过某些对光线不透明的物体进行读取成为可能，或者通过能够更容易地扫描更大的读取区域来显着减少标识符的获取时间。的简历。将在intérêt牛角面包上存在实际情况，例如，在系统、通信、通信和移动方面，在可能的情况下，在电池、化学成分和污染物方面，都存在实际情况，例如，在电池、化学成分和污染物方面。如果你对通讯的原理进行了分析，那么你就可以对通讯的原理进行分析，你就可以对通讯的原理进行分析，你就可以对通讯的原理进行分析，你就可以对通讯的原理进行分析，你就可以对通讯的原理进行分析。在这两个例子中，将“agit d’utiliser”定义为“特征雷达”。lagsamomsamtrie des samlsamims imprim sams sur cell -ci - ciant samt - spsamcialement conconue pour remplir les功能sohaitsames。这些新系统的新功能可以帮助人们解决一些问题，例如:mêmes选择特定的功能，例如:特定的营养，特定的应用，例如:être在某些应用中，特定的应用可以帮助人们解决一些问题，例如:où新系统的新功能可以帮助人们解决一些问题。在代码壁垒的基础上建立良好的关系，在代码壁垒的基础上建立良好的优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势，在代码壁垒的基础上建立优势。
{"title":"Chipless labels detection by backscattering for identification and sensing applications","authors":"E. Perret","doi":"10.5802/crphys.95","DOIUrl":"https://doi.org/10.5802/crphys.95","url":null,"abstract":"There is currently a growing interest in the development of communication systems that consume as little energy as possible, with the idea of eliminating the presence of batteries, which are a very polluting component. This is why the principles of communication based on backscatter modulation, or even more simply on backscattering by a device that takes the form of a label, like a barcode, are being studied more and more. In the latter case, the idea is to use the radar signature of this totally passive label, the geometry of the elements printed on it having been specially designed to perform the desired functions. These new systems cannot claim to do the same things as those working with a power supply or a chip, but they may be of interest for certain applications where the reading distances do not exceed one metre. Compared to barcodes, the main advantages are related to the use of RF waves to communicate, which makes it possible to read through certain objects that are opaque to light, or to significantly reduce the acquisition time of identifiers by being able to scan larger reading areas more easily. Résumé. Il existe actuellement un intérêt croissant pour le développement de systèmes de communication consommant le moins d’énergie possible, avec l’idée d’éliminer la présence de batteries, qui sont des composants très polluants. C’est pourquoi on étudie de plus en plus les principes de communication RF basés sur la retro-modulation, ou même plus simplement sur la rétrodiffusion d’une onde par un dispositif qui prend la forme d’une étiquette, comme un code-barres. Dans ce dernier cas, il s’agit d’utiliser la signature radar de cette étiquette totalement passive ; la géométrie des éléments imprimés sur celle-ci ayant été spécialement conçue pour remplir les fonctions souhaitées. Ces nouveaux systèmes ne peuvent prétendre faire les mêmes choses que ceux fonctionnant avec une alimentation ou une puce, mais ils peuvent être intéressants pour certaines applications où les distances de lecture ne dépassent pas un mètre. Par rapport aux code-barres, les principaux avantages sont liés à l’utilisation des ondes RF pour communiquer, ce qui permet de lire à travers certains objets opaques à la lumière ou encore de réduire significativement le temps d’acquisition des identifiants en pouvant balayer plus facilement de plus grandes zones de lecture.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48805012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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