Project acronym A2C2
Project Atmospheric flow Analogues and Climate Change
Researcher (PI) Pascal Yiou
Host Institution (HI) COMMISSARIAT A L ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
Call Details Advanced Grant (AdG), PE10, ERC-2013-ADG
Summary "The A2C2 project treats two major challenges in climate and atmospheric research: the time dependence of the climate attractor to external forcings (solar, volcanic eruptions and anthropogenic), and the attribution of extreme climate events occurring in the northern extra-tropics. The main difficulties are the limited climate information, the computer cost of model simulations, and mathematical assumptions that are hardly verified and often overlooked in the literature.
A2C2 proposes a practical framework to overcome those three difficulties, linking the theory of dynamical systems and statistics. We will generalize the methodology of flow analogues to multiple databases in order to obtain probabilistic descriptions of analogue decompositions.
The project is divided into three workpackages (WP). WP1 embeds the analogue method in the theory of dynamical systems in order to provide a metric of an attractor deformation in time. The important methodological step is to detect trends or persisting outliers in the dates and scores of analogues when the system yields time-varying forcings. This is done from idealized models and full size climate models in which the forcings (anthropogenic and natural) are known.
A2C2 creates an open source toolkit to compute flow analogues from a wide array of databases (WP2). WP3 treats the two scientific challenges with the analogue method and multiple model ensembles, hence allowing uncertainty estimates under realistic mathematical hypotheses. The flow analogue methodology allows a systematic and quasi real-time analysis of extreme events, which is currently out of the reach of conventional climate modeling approaches.
The major breakthrough of A2C2 is to bridge the gap between operational needs (the immediate analysis of climate events) and the understanding long-term climate changes. A2C2 opens new research horizons for the exploitation of ensembles of simulations and reliable estimates of uncertainty."
Summary
"The A2C2 project treats two major challenges in climate and atmospheric research: the time dependence of the climate attractor to external forcings (solar, volcanic eruptions and anthropogenic), and the attribution of extreme climate events occurring in the northern extra-tropics. The main difficulties are the limited climate information, the computer cost of model simulations, and mathematical assumptions that are hardly verified and often overlooked in the literature.
A2C2 proposes a practical framework to overcome those three difficulties, linking the theory of dynamical systems and statistics. We will generalize the methodology of flow analogues to multiple databases in order to obtain probabilistic descriptions of analogue decompositions.
The project is divided into three workpackages (WP). WP1 embeds the analogue method in the theory of dynamical systems in order to provide a metric of an attractor deformation in time. The important methodological step is to detect trends or persisting outliers in the dates and scores of analogues when the system yields time-varying forcings. This is done from idealized models and full size climate models in which the forcings (anthropogenic and natural) are known.
A2C2 creates an open source toolkit to compute flow analogues from a wide array of databases (WP2). WP3 treats the two scientific challenges with the analogue method and multiple model ensembles, hence allowing uncertainty estimates under realistic mathematical hypotheses. The flow analogue methodology allows a systematic and quasi real-time analysis of extreme events, which is currently out of the reach of conventional climate modeling approaches.
The major breakthrough of A2C2 is to bridge the gap between operational needs (the immediate analysis of climate events) and the understanding long-term climate changes. A2C2 opens new research horizons for the exploitation of ensembles of simulations and reliable estimates of uncertainty."
Max ERC Funding
1 491 457 €
Duration
Start date: 2014-03-01, End date: 2019-02-28
Project acronym ACCLIMATE
Project Elucidating the Causes and Effects of Atlantic Circulation Changes through Model-Data Integration
Researcher (PI) Claire Waelbroeck
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Advanced Grant (AdG), PE10, ERC-2013-ADG
Summary Rapid changes in ocean circulation and climate have been observed in marine sediment and ice cores, notably over the last 60 thousand years (ky), highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing.
To date, these rapid changes in climate and ocean circulation are still not fully explained. Two main obstacles prevent going beyond the current state of knowledge:
- Paleoclimatic proxy data are by essence only indirect indicators of the climatic variables, and thus can not be directly compared with model outputs;
- A 4-D (latitude, longitude, water depth, time) reconstruction of Atlantic water masses over the past 40 ky is lacking: previous studies have generated isolated records with disparate timescales which do not allow the causes of circulation changes to be identified.
Overcoming these two major limitations will lead to major breakthroughs in climate research. Concretely, I will create the first database of Atlantic deep-sea records over the last 40 ky, and extract full climatic information from these records through an innovative model-data integration scheme using an isotopic proxy forward modeling approach. The novelty and exceptional potential of this scheme is twofold: (i) it avoids hypotheses on proxy interpretation and hence suppresses or strongly reduces the errors of interpretation of paleoclimatic records; (ii) it produces states of the climate system that best explain the observations over the last 40 ky, while being consistent with the model physics.
Expected results include:
• The elucidation of the mechanisms explaining rapid changes in ocean circulation and climate over the last 40 ky,
• Improved climate model physics and parameterizations,
• The first projections of future climate changes obtained with a model able to reproduce the highly non linear behavior of the climate system observed over the last 40 ky.
Summary
Rapid changes in ocean circulation and climate have been observed in marine sediment and ice cores, notably over the last 60 thousand years (ky), highlighting the non-linear character of the climate system and underlining the possibility of rapid climate shifts in response to anthropogenic greenhouse gas forcing.
To date, these rapid changes in climate and ocean circulation are still not fully explained. Two main obstacles prevent going beyond the current state of knowledge:
- Paleoclimatic proxy data are by essence only indirect indicators of the climatic variables, and thus can not be directly compared with model outputs;
- A 4-D (latitude, longitude, water depth, time) reconstruction of Atlantic water masses over the past 40 ky is lacking: previous studies have generated isolated records with disparate timescales which do not allow the causes of circulation changes to be identified.
Overcoming these two major limitations will lead to major breakthroughs in climate research. Concretely, I will create the first database of Atlantic deep-sea records over the last 40 ky, and extract full climatic information from these records through an innovative model-data integration scheme using an isotopic proxy forward modeling approach. The novelty and exceptional potential of this scheme is twofold: (i) it avoids hypotheses on proxy interpretation and hence suppresses or strongly reduces the errors of interpretation of paleoclimatic records; (ii) it produces states of the climate system that best explain the observations over the last 40 ky, while being consistent with the model physics.
Expected results include:
• The elucidation of the mechanisms explaining rapid changes in ocean circulation and climate over the last 40 ky,
• Improved climate model physics and parameterizations,
• The first projections of future climate changes obtained with a model able to reproduce the highly non linear behavior of the climate system observed over the last 40 ky.
Max ERC Funding
3 000 000 €
Duration
Start date: 2014-02-01, End date: 2019-01-31
Project acronym ADAM
Project The Adaptive Auditory Mind
Researcher (PI) Shihab Shamma
Host Institution (HI) ECOLE NORMALE SUPERIEURE
Call Details Advanced Grant (AdG), SH4, ERC-2011-ADG_20110406
Summary Listening in realistic situations is an active process that engages perceptual and cognitive faculties, endowing speech with meaning, music with joy, and environmental sounds with emotion. Through hearing, humans and other animals navigate complex acoustic scenes, separate sound mixtures, and assess their behavioral relevance. These remarkable feats are currently beyond our understanding and exceed the capabilities of the most sophisticated audio engineering systems. The goal of the proposed research is to investigate experimentally a novel view of hearing, where active hearing emerges from a deep interplay between adaptive sensory processes and goal-directed cognition. Specifically, we shall explore the postulate that versatile perception is mediated by rapid-plasticity at the neuronal level. At the conjunction of sensory and cognitive processing, rapid-plasticity pervades all levels of auditory system, from the cochlea up to the auditory and prefrontal cortices. Exploiting fundamental statistical regularities of acoustics, it is what allows humans and other animal to deal so successfully with natural acoustic scenes where artificial systems fail. The project builds on the internationally recognized leadership of the PI in the fields of physiology and computational modeling, combined with the expertise of the Co-Investigator in psychophysics. Building on these highly complementary fields and several technical innovations, we hope to promote a novel view of auditory perception and cognition. We aim also to contribute significantly to translational research in the domain of signal processing for clinical hearing aids, given that many current limitations are not technological but rather conceptual. The project will finally result in the creation of laboratory facilities and an intellectual network unique in France and rare in all of Europe, combining cognitive, neural, and computational approaches to auditory neuroscience.
Summary
Listening in realistic situations is an active process that engages perceptual and cognitive faculties, endowing speech with meaning, music with joy, and environmental sounds with emotion. Through hearing, humans and other animals navigate complex acoustic scenes, separate sound mixtures, and assess their behavioral relevance. These remarkable feats are currently beyond our understanding and exceed the capabilities of the most sophisticated audio engineering systems. The goal of the proposed research is to investigate experimentally a novel view of hearing, where active hearing emerges from a deep interplay between adaptive sensory processes and goal-directed cognition. Specifically, we shall explore the postulate that versatile perception is mediated by rapid-plasticity at the neuronal level. At the conjunction of sensory and cognitive processing, rapid-plasticity pervades all levels of auditory system, from the cochlea up to the auditory and prefrontal cortices. Exploiting fundamental statistical regularities of acoustics, it is what allows humans and other animal to deal so successfully with natural acoustic scenes where artificial systems fail. The project builds on the internationally recognized leadership of the PI in the fields of physiology and computational modeling, combined with the expertise of the Co-Investigator in psychophysics. Building on these highly complementary fields and several technical innovations, we hope to promote a novel view of auditory perception and cognition. We aim also to contribute significantly to translational research in the domain of signal processing for clinical hearing aids, given that many current limitations are not technological but rather conceptual. The project will finally result in the creation of laboratory facilities and an intellectual network unique in France and rare in all of Europe, combining cognitive, neural, and computational approaches to auditory neuroscience.
Max ERC Funding
3 199 078 €
Duration
Start date: 2012-10-01, End date: 2018-09-30
Project acronym ADEQUATE
Project Advanced optoelectronic Devices with Enhanced QUAntum efficiency at THz frEquencies
Researcher (PI) Carlo Sirtori
Host Institution (HI) UNIVERSITE PARIS DIDEROT - PARIS 7
Call Details Advanced Grant (AdG), PE3, ERC-2009-AdG
Summary The aim of this project is the realisation of efficient mid-infrared and THz optoelectronic emitters. This work is motivated by the fact that the spontaneous emission in this frequency range is characterized by an extremely long lifetime when compared to non-radiative processes, giving rise to devices with very low quantum efficiency. To this end we want to develop hybrid light-matter systems, already well known in quantum optics, within optoelectronics devices, that will be driven by electrical injection. With this project we want to extend the field of optoelectronics by introducing some of the concepts of quantum optic, particularly the light-matter strong coupling, into semiconductor devices. More precisely this project aims at the implementation of novel optoelectronic emitters operating in the strong coupling regime between an intersubband excitation of a two-dimensional electron gas and a microcavity photonic mode. The quasiparticles issued from this coupling are called intersubband polaritons. The major difficulties and challenges of this project, do not lay in the observation of these quantum effects, but in their exploitation for a specific function, in particular an efficient electrical to optical conversion. To obtain efficient quantum emitters in the THz frequency range we will follow two different approaches: - In the first case we will try to exploit the additional characteristic time of the system introduced by the light-matter interaction in the strong (or ultra-strong) coupling regime. - The second approach will exploit the fact that, under certain conditions, intersubband polaritons have a bosonic character; as a consequence they can undergo stimulated scattering, giving rise to polaritons lasers as it has been shown for excitonic polaritons.
Summary
The aim of this project is the realisation of efficient mid-infrared and THz optoelectronic emitters. This work is motivated by the fact that the spontaneous emission in this frequency range is characterized by an extremely long lifetime when compared to non-radiative processes, giving rise to devices with very low quantum efficiency. To this end we want to develop hybrid light-matter systems, already well known in quantum optics, within optoelectronics devices, that will be driven by electrical injection. With this project we want to extend the field of optoelectronics by introducing some of the concepts of quantum optic, particularly the light-matter strong coupling, into semiconductor devices. More precisely this project aims at the implementation of novel optoelectronic emitters operating in the strong coupling regime between an intersubband excitation of a two-dimensional electron gas and a microcavity photonic mode. The quasiparticles issued from this coupling are called intersubband polaritons. The major difficulties and challenges of this project, do not lay in the observation of these quantum effects, but in their exploitation for a specific function, in particular an efficient electrical to optical conversion. To obtain efficient quantum emitters in the THz frequency range we will follow two different approaches: - In the first case we will try to exploit the additional characteristic time of the system introduced by the light-matter interaction in the strong (or ultra-strong) coupling regime. - The second approach will exploit the fact that, under certain conditions, intersubband polaritons have a bosonic character; as a consequence they can undergo stimulated scattering, giving rise to polaritons lasers as it has been shown for excitonic polaritons.
Max ERC Funding
1 761 000 €
Duration
Start date: 2010-05-01, End date: 2015-04-30
Project acronym AIRSEA
Project Air-Sea Exchanges driven by Light
Researcher (PI) Christian George
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Advanced Grant (AdG), PE10, ERC-2011-ADG_20110209
Summary The scientific motivation of this project is the significant presence of organic compounds at the surface of the ocean. They form the link between ocean biogeochemistry through the physico-chemical processes near the water-air interface with primary and secondary aerosol formation and evolution in the air aloft and finally to the climate impact of marine boundary layer aerosols. However, their photochemistry and photosensitizer properties have only been suggested and discussed but never fully addressed because they were beyond reach. This project suggests going significantly beyond this matter of fact by a combination of innovative tools and the development of new ideas.
This project is therefore devoted to new laboratory investigations of processes occurring at the air sea interface to predict emission, formation and evolution of halogenated radicals and aerosols from this vast interface between oceans and atmosphere. It progresses from fundamental laboratory measurements, marine science, surface chemistry, photochemistry … and is therefore interdisciplinary in nature.
It will lead to the development of innovative techniques for characterising chemical processing at the air sea interface (e.g., a multiphase atmospheric simulation chamber, a time-resolved fluorescence technique for characterising chemical processing at the air-sea interface). It will allow the assessment of new emerging ideas such as a quantitative description of the importance of photosensitized reactions in the visible at the air/sea interface as a major source of halogenated radicals and aerosols in the marine environment.
This new understanding will impact on our ability to describe atmospheric chemistry in the marine environment which has strong impact on the urban air quality of coastal regions (which by the way represent highly populated regions ) but also on climate change by providing new input for global climate models.
Summary
The scientific motivation of this project is the significant presence of organic compounds at the surface of the ocean. They form the link between ocean biogeochemistry through the physico-chemical processes near the water-air interface with primary and secondary aerosol formation and evolution in the air aloft and finally to the climate impact of marine boundary layer aerosols. However, their photochemistry and photosensitizer properties have only been suggested and discussed but never fully addressed because they were beyond reach. This project suggests going significantly beyond this matter of fact by a combination of innovative tools and the development of new ideas.
This project is therefore devoted to new laboratory investigations of processes occurring at the air sea interface to predict emission, formation and evolution of halogenated radicals and aerosols from this vast interface between oceans and atmosphere. It progresses from fundamental laboratory measurements, marine science, surface chemistry, photochemistry … and is therefore interdisciplinary in nature.
It will lead to the development of innovative techniques for characterising chemical processing at the air sea interface (e.g., a multiphase atmospheric simulation chamber, a time-resolved fluorescence technique for characterising chemical processing at the air-sea interface). It will allow the assessment of new emerging ideas such as a quantitative description of the importance of photosensitized reactions in the visible at the air/sea interface as a major source of halogenated radicals and aerosols in the marine environment.
This new understanding will impact on our ability to describe atmospheric chemistry in the marine environment which has strong impact on the urban air quality of coastal regions (which by the way represent highly populated regions ) but also on climate change by providing new input for global climate models.
Max ERC Funding
2 366 276 €
Duration
Start date: 2012-04-01, End date: 2017-03-31
Project acronym ATOMAG
Project From Attosecond Magnetism towards Ultrafast Spin Photonics
Researcher (PI) Jean-Yves Bigot
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Advanced Grant (AdG), PE3, ERC-2009-AdG
Summary We propose to investigate a new frontier in Physics: the study of Magnetic systems using attosecond laser pulses. The main disciplines concerned are: Ultrafast laser sciences, Magnetism and Spin-Photonics, Relativistic Quantum Electrodynamics. Three issues of modern magnetism are addressed. 1. How fast can one modify and control the magnetization of a magnetic system ? 2. What is the role and essence of the coherent interaction between light and spins ? 3. How far spin-photonics can bring us to the real world of data acquisition and storage ? - We want first to provide solid ground experiments, unravelling the mechanisms involved in the demagnetization induced by laser pulses in a variety of magnetic materials (ferromagnetic nanostructures, aggregates and molecular magnets). We will explore the ultrafast magnetization dynamics of magnets using an attosecond laser source. - Second we want to explore how the photon field interacts with the spins. We will investigate the dynamical regime when the potential of the atoms is dressed by the Coulomb potential induced by the laser field. A strong support from the relativistic Quantum Electro-Dynamics is necessary towards that goal. - Third, even though our general approach is fundamental, we want to provide a benchmark of what is realistically possible in ultrafast spin-photonics, breaking the conventional thought that spin photonics is hard to implement at the application level. We will realize ultimate devices combining magneto-optical microscopy with the conventional magnetic recording. This new field will raise the interest of a number of competitive laboratories at the international level. Due to the overlapping disciplines the project also carries a large amount of educational impact both fundamental and applied.
Summary
We propose to investigate a new frontier in Physics: the study of Magnetic systems using attosecond laser pulses. The main disciplines concerned are: Ultrafast laser sciences, Magnetism and Spin-Photonics, Relativistic Quantum Electrodynamics. Three issues of modern magnetism are addressed. 1. How fast can one modify and control the magnetization of a magnetic system ? 2. What is the role and essence of the coherent interaction between light and spins ? 3. How far spin-photonics can bring us to the real world of data acquisition and storage ? - We want first to provide solid ground experiments, unravelling the mechanisms involved in the demagnetization induced by laser pulses in a variety of magnetic materials (ferromagnetic nanostructures, aggregates and molecular magnets). We will explore the ultrafast magnetization dynamics of magnets using an attosecond laser source. - Second we want to explore how the photon field interacts with the spins. We will investigate the dynamical regime when the potential of the atoms is dressed by the Coulomb potential induced by the laser field. A strong support from the relativistic Quantum Electro-Dynamics is necessary towards that goal. - Third, even though our general approach is fundamental, we want to provide a benchmark of what is realistically possible in ultrafast spin-photonics, breaking the conventional thought that spin photonics is hard to implement at the application level. We will realize ultimate devices combining magneto-optical microscopy with the conventional magnetic recording. This new field will raise the interest of a number of competitive laboratories at the international level. Due to the overlapping disciplines the project also carries a large amount of educational impact both fundamental and applied.
Max ERC Funding
2 492 561 €
Duration
Start date: 2010-05-01, End date: 2015-04-30
Project acronym Babylearn
Project Neural mechanisms of learning in the infant brain : from Statistics to Rules and Symbols
Researcher (PI) Ghislaine, Marie-Therese, Aline DEHAENE-LAMBERTZ
Host Institution (HI) COMMISSARIAT A L ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
Call Details Advanced Grant (AdG), SH4, ERC-2015-AdG
Summary Infant is the most powerful learner: He learns in a few months to master language, complex social interactions, etc. Powerful statistical algorithms, simultaneously acting at the different levels of functional hierarchies have been proposed to explain learning. I propose here that two other elements are crucial. The first is the particular human cerebral architecture that constrains statistical computations. The second is the human’s ability to access a rich symbolic system. I have planned 6 work packages using the complementary information offered by non-invasive brain-imaging techniques (EEG, MRI and optical topography) to understand the neural bases of infant statistical computations and symbolic competence from 6 months of gestation up until the end of the first year of life.
WP1 studies from which preterm age, statistical inferences can be demonstrated using hierarchical auditory oddball paradigms.
WP2 investigates the consequences of a different pre-term environment (in-utero versus ex-utero) on the early statistical computations in the visual and auditory domains and their consequences on the ongoing brain activity along the first year of life.
WP3 explores the neural bases of how infants infer word meaning and word category, and in particular the role of the left perisylvian areas and of their particular connectivity.
WP4 questions infant symbolic competency. I propose several criteria (generalization, bidirectionality, use of algebraic rules and of logical operations) tested in successive experiments to clarify infant symbolic abilities during the first semester of life.
WP5-6 are transversal to WP1-4: WP5 uses MRI to obtain accurate functional localization and maturational markers correlated with functional results. In WP6, we develop new tools to combine and analyse multimodal brain images.
With this proposal, I hope to clarify the specificities of a neural functional architecture that are critical for human learning from the onset of cortical circuits.
Summary
Infant is the most powerful learner: He learns in a few months to master language, complex social interactions, etc. Powerful statistical algorithms, simultaneously acting at the different levels of functional hierarchies have been proposed to explain learning. I propose here that two other elements are crucial. The first is the particular human cerebral architecture that constrains statistical computations. The second is the human’s ability to access a rich symbolic system. I have planned 6 work packages using the complementary information offered by non-invasive brain-imaging techniques (EEG, MRI and optical topography) to understand the neural bases of infant statistical computations and symbolic competence from 6 months of gestation up until the end of the first year of life.
WP1 studies from which preterm age, statistical inferences can be demonstrated using hierarchical auditory oddball paradigms.
WP2 investigates the consequences of a different pre-term environment (in-utero versus ex-utero) on the early statistical computations in the visual and auditory domains and their consequences on the ongoing brain activity along the first year of life.
WP3 explores the neural bases of how infants infer word meaning and word category, and in particular the role of the left perisylvian areas and of their particular connectivity.
WP4 questions infant symbolic competency. I propose several criteria (generalization, bidirectionality, use of algebraic rules and of logical operations) tested in successive experiments to clarify infant symbolic abilities during the first semester of life.
WP5-6 are transversal to WP1-4: WP5 uses MRI to obtain accurate functional localization and maturational markers correlated with functional results. In WP6, we develop new tools to combine and analyse multimodal brain images.
With this proposal, I hope to clarify the specificities of a neural functional architecture that are critical for human learning from the onset of cortical circuits.
Max ERC Funding
2 554 924 €
Duration
Start date: 2016-09-01, End date: 2021-08-31
Project acronym BALLISTOP
Project Revealing 1D ballistic charge and spin currents in second order topological insulators
Researcher (PI) helene BOUCHIAT
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Call Details Advanced Grant (AdG), PE3, ERC-2018-ADG
Summary One of the greatest recent achievement in Condensed matter physics is the discovery of a new class of materials, Topological Insulators (TI), whose bulk is insulating, while the edges conduct current in a quasi-ideal way. In particular, the 1D edges of 2DTI realize the Quantum Spin Hall state, where current is carried dissipationlessly by two counter-propagating ballistic edge states with a spin orientation locked to that of the propagation direction (a helical edge state). This opens many possibilities, ranging from dissipationless charge and spin transport at room temperature to new avenues for quantum computing. We propose to investigate charge and spin currents in a newly discovered class of TIs, Second Order Topological Insulators (SOTIs), i.e. 3D crystals with insulating bulk and surfaces, but perfectly conducting (topologically protected) 1D helical “hinge” states. Bismuth, despite its well-known semimetallic character, has recently been shown theoretically to belong to this class of materials, explaining our recent intriguing findings on nanowires. Our goal is to reveal, characterize and exploit the unique properties of SOTIs, in particular the high velocity, ballistic, and dissipationless hinge currents. We will probe crystalline bismuth samples with refined new experimental tools. The superconducting proximity effect will reveal the spatial distribution of conduction paths, and test the ballisticity of the hinge modes (that may coexist with non-topological surface modes). High frequency and tunnel spectroscopies of hybrid superconductor/Bi circuits will probe their topological nature, including the existence of Majorana modes. We will use high sensitivity magnetometers to detect the orbital magnetism of SOTI platelets, which should be dominated by topological edge currents. Lastly, we propose to detect the predicted equilibrium spin currents in 2DTIs and SOTIs via the generated electric field, using single electron transistors-based electrometers.
Summary
One of the greatest recent achievement in Condensed matter physics is the discovery of a new class of materials, Topological Insulators (TI), whose bulk is insulating, while the edges conduct current in a quasi-ideal way. In particular, the 1D edges of 2DTI realize the Quantum Spin Hall state, where current is carried dissipationlessly by two counter-propagating ballistic edge states with a spin orientation locked to that of the propagation direction (a helical edge state). This opens many possibilities, ranging from dissipationless charge and spin transport at room temperature to new avenues for quantum computing. We propose to investigate charge and spin currents in a newly discovered class of TIs, Second Order Topological Insulators (SOTIs), i.e. 3D crystals with insulating bulk and surfaces, but perfectly conducting (topologically protected) 1D helical “hinge” states. Bismuth, despite its well-known semimetallic character, has recently been shown theoretically to belong to this class of materials, explaining our recent intriguing findings on nanowires. Our goal is to reveal, characterize and exploit the unique properties of SOTIs, in particular the high velocity, ballistic, and dissipationless hinge currents. We will probe crystalline bismuth samples with refined new experimental tools. The superconducting proximity effect will reveal the spatial distribution of conduction paths, and test the ballisticity of the hinge modes (that may coexist with non-topological surface modes). High frequency and tunnel spectroscopies of hybrid superconductor/Bi circuits will probe their topological nature, including the existence of Majorana modes. We will use high sensitivity magnetometers to detect the orbital magnetism of SOTI platelets, which should be dominated by topological edge currents. Lastly, we propose to detect the predicted equilibrium spin currents in 2DTIs and SOTIs via the generated electric field, using single electron transistors-based electrometers.
Max ERC Funding
2 432 676 €
Duration
Start date: 2020-04-01, End date: 2025-03-31
Project acronym BOOTPHON
Project A computational approach to early language bootstrapping
Researcher (PI) Emmanuel Dupoux
Host Institution (HI) ECOLE DES HAUTES ETUDES EN SCIENCES SOCIALES
Call Details Advanced Grant (AdG), SH4, ERC-2011-ADG_20110406
Summary "During their first year of life, infants become attuned to the phonemes, words and phonological rules of their language, with little or no adult supervision. After 30 years of accumulated experimental results, we are still lacking an account for the puzzling fact that these 3 interdependent components of language are acquired not sequentially, but in parallel. Drawing tools from Machine Learning and Automatic Speech Recognition, we construct a model of this early process, test it on 2 large spontaneous speech databases (Japanese, French and Dutch) and test its predictions in infants using behavioral, EEGs and fNIRS techniques.
1. Coding. We study different ways of defining coding features for speech, from fine-grained to coarse grained, in view of the automatic discovery of a hierarchy of linguistic units. We compare this with a systematic study of the units of speech coding as they unfold in 6, 9 and 12 month old infants..
2. Lexicon. Infants recognize some words before they know the phonemes of their language; we modify existing word segmentation algorithms so they can work on raw speech. We test the unique prediction that infants start with a large lexicon that’s quite different from the adult one.
3. Rules. Phonemes are produced as overlapping, coarticulated gestures. To untangle these context effects, we use a predictive model of coarticulation in auditory space and invert it. We test when and how infants perform reverse coarticulation.
4. Integration. The above subprojects provide only an initial bootstrapping into approximate phonemes, words, and contextual rules. We show how to iteratively integrate these approximate representations to derive better ones. The outcome will be numerically assessed on an adult directed and infant directed speech database, and compared to those of to state-of-the-art supervized phoneme recognizers. The predictions will be tested in infants learning artificial languages and in a longitudinal study."
Summary
"During their first year of life, infants become attuned to the phonemes, words and phonological rules of their language, with little or no adult supervision. After 30 years of accumulated experimental results, we are still lacking an account for the puzzling fact that these 3 interdependent components of language are acquired not sequentially, but in parallel. Drawing tools from Machine Learning and Automatic Speech Recognition, we construct a model of this early process, test it on 2 large spontaneous speech databases (Japanese, French and Dutch) and test its predictions in infants using behavioral, EEGs and fNIRS techniques.
1. Coding. We study different ways of defining coding features for speech, from fine-grained to coarse grained, in view of the automatic discovery of a hierarchy of linguistic units. We compare this with a systematic study of the units of speech coding as they unfold in 6, 9 and 12 month old infants..
2. Lexicon. Infants recognize some words before they know the phonemes of their language; we modify existing word segmentation algorithms so they can work on raw speech. We test the unique prediction that infants start with a large lexicon that’s quite different from the adult one.
3. Rules. Phonemes are produced as overlapping, coarticulated gestures. To untangle these context effects, we use a predictive model of coarticulation in auditory space and invert it. We test when and how infants perform reverse coarticulation.
4. Integration. The above subprojects provide only an initial bootstrapping into approximate phonemes, words, and contextual rules. We show how to iteratively integrate these approximate representations to derive better ones. The outcome will be numerically assessed on an adult directed and infant directed speech database, and compared to those of to state-of-the-art supervized phoneme recognizers. The predictions will be tested in infants learning artificial languages and in a longitudinal study."
Max ERC Funding
2 194 557 €
Duration
Start date: 2012-11-01, End date: 2017-10-31
Project acronym BRAVIUS
Project Brain-viscera interactions underlie subjectivity
Researcher (PI) Catherine Tallon-Baudry
Host Institution (HI) ECOLE NORMALE SUPERIEURE
Call Details Advanced Grant (AdG), SH4, ERC-2014-ADG
Summary Subjectivity defines the subject who is perceiving, feeling, thinking, acting, and is essential to understand the conscious mind from the inside. However, subjectivity, or non-reflective first-person perspective, is not identified as a core concept in cognitive neuroscience and its neural basis remain largely unknown. BRAVIUS offers a unified framework to appraise both the concept and the neural mechanisms generating subjectivity. The hypothesis relies on two vital organs that generate their own rhythmic electrical activity, the stomach and the heart, and therefore constantly send information up to the neocortex, even in the absence of bodily change. Cortical responses to those visceral organs would define the organism as an entity at the neural level, and create a subject-centered referential from which first-person perspective can develop. In other words, the cardiac and gastric pacemakers could feed the brain with self-specifying inputs. BRAVIUS builds on previous theories and studies on visceral states but focuses on ascending information, from viscera to brain, and does not require visceral states to change nor to be consciously perceived. Experimentally, BRAVIUS measures the understudied neural response evoked by heartbeats and introduces a new measure, the electrogastrogram, to quantify the slow gastric pacemaker. BRAVIUS will test with magneto-encephalography (MEG) the role of neural responses to ascending visceral signals in generating subjectivity by cutting across domains of cognitive sciences and exploring diverse paradigms where subjectivity is engaged: perceptual consciousness, self-consciousness, emotions and decision making. BRAVIUS will further explore how cardiac and gastric ascending signals shape the temporal (MEG) and spatial (fMRI) organization of spontaneous brain activity. The project outcome is a detailed mechanistic neural account of the most private part of the human mind, and a unified concept of subjectivity across cognitive domains.
Summary
Subjectivity defines the subject who is perceiving, feeling, thinking, acting, and is essential to understand the conscious mind from the inside. However, subjectivity, or non-reflective first-person perspective, is not identified as a core concept in cognitive neuroscience and its neural basis remain largely unknown. BRAVIUS offers a unified framework to appraise both the concept and the neural mechanisms generating subjectivity. The hypothesis relies on two vital organs that generate their own rhythmic electrical activity, the stomach and the heart, and therefore constantly send information up to the neocortex, even in the absence of bodily change. Cortical responses to those visceral organs would define the organism as an entity at the neural level, and create a subject-centered referential from which first-person perspective can develop. In other words, the cardiac and gastric pacemakers could feed the brain with self-specifying inputs. BRAVIUS builds on previous theories and studies on visceral states but focuses on ascending information, from viscera to brain, and does not require visceral states to change nor to be consciously perceived. Experimentally, BRAVIUS measures the understudied neural response evoked by heartbeats and introduces a new measure, the electrogastrogram, to quantify the slow gastric pacemaker. BRAVIUS will test with magneto-encephalography (MEG) the role of neural responses to ascending visceral signals in generating subjectivity by cutting across domains of cognitive sciences and exploring diverse paradigms where subjectivity is engaged: perceptual consciousness, self-consciousness, emotions and decision making. BRAVIUS will further explore how cardiac and gastric ascending signals shape the temporal (MEG) and spatial (fMRI) organization of spontaneous brain activity. The project outcome is a detailed mechanistic neural account of the most private part of the human mind, and a unified concept of subjectivity across cognitive domains.
Max ERC Funding
2 080 000 €
Duration
Start date: 2015-12-01, End date: 2020-11-30