Project acronym CRYVISIL
Project Crystalline and vitreous silica films and their interconversion
Researcher (PI) Hans-Joachim Freund
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Call Details Advanced Grant (AdG), PE4, ERC-2014-ADG
Summary Silicon is the most abundant element in the earth’s crust. Its oxide, silica (SiO2) is the basis for most minerals of the earth’s crust, and also for a number of technological applications ranging from window glass, via electronics to catalysis. The structure of crystalline materials such as quartz or silica-based minerals is well understood due to the application of scattering techniques such as x-ray or neutron diffraction, for example, which allow accurate structure determinations. Silica, however, also forms glasses, which are amorphous or vitreous. Its structure is not well understood. In fact, diffraction techniques have only been able to deliver pair correlation functions, which reveal the density of a material around a given atom, but do not allow a detailed reconstruction of the atomic structure as in the case of crystalline materials. Until recently, a real space image of a silica glass with atomic resolution had not been recorded. Using scanning probe techniques applied to a thin silica film grown atomically flat on a metal substrate, it has been possible to reveal, for the first time, an atomically resolved image of vitreous silica. Both, a crystalline as well as a vitreous phase have been imaged. With this system, it is now possible to address the transition from a vitreous state to a crystal-line in real space by developing a scanning probe microscope that allows the study of its structure over a wide range of temperatures ranging from cryogenic temperatures to 1500 K. It is the purpose of this grant application to build such a device and apply it to the crystal-glass transition and the study of vibrational properties. This instrument may also be used to address a number of scientific problems related to other glass-formers, such as borates and the influence of silica modifications by atom doping, for example.
Summary
Silicon is the most abundant element in the earth’s crust. Its oxide, silica (SiO2) is the basis for most minerals of the earth’s crust, and also for a number of technological applications ranging from window glass, via electronics to catalysis. The structure of crystalline materials such as quartz or silica-based minerals is well understood due to the application of scattering techniques such as x-ray or neutron diffraction, for example, which allow accurate structure determinations. Silica, however, also forms glasses, which are amorphous or vitreous. Its structure is not well understood. In fact, diffraction techniques have only been able to deliver pair correlation functions, which reveal the density of a material around a given atom, but do not allow a detailed reconstruction of the atomic structure as in the case of crystalline materials. Until recently, a real space image of a silica glass with atomic resolution had not been recorded. Using scanning probe techniques applied to a thin silica film grown atomically flat on a metal substrate, it has been possible to reveal, for the first time, an atomically resolved image of vitreous silica. Both, a crystalline as well as a vitreous phase have been imaged. With this system, it is now possible to address the transition from a vitreous state to a crystal-line in real space by developing a scanning probe microscope that allows the study of its structure over a wide range of temperatures ranging from cryogenic temperatures to 1500 K. It is the purpose of this grant application to build such a device and apply it to the crystal-glass transition and the study of vibrational properties. This instrument may also be used to address a number of scientific problems related to other glass-formers, such as borates and the influence of silica modifications by atom doping, for example.
Max ERC Funding
2 484 375 €
Duration
Start date: 2016-01-01, End date: 2020-12-31
Project acronym D5S
Project Direct Statistical Simulation of the Sun and Stars
Researcher (PI) Steven Tobias
Host Institution (HI) UNIVERSITY OF LEEDS
Call Details Advanced Grant (AdG), PE9, ERC-2017-ADG
Summary This proposal (D5S) addresses a key problem of astrophysics – the origin of magnetic activity in the sun and solar-type
stars. This is a problem not only of outstanding theoretical importance but also significant practical impact – solar activity has
major terrestrial consequences. An increase in activity can lead to an increase in the number and violence of solar flares and
coronal mass ejections, with profound consequences for our terrestrial environment, causing disruption to satellites and
power. Predictions of magnetic activity are highly desired by government and industry groups alike. A deep understanding of
the mechanisms leading to solar magnetic activity is required. The variable magnetic field is generated by a dynamo in the
solar interior. Though this mechanism is known to involve the interaction of magnetohydrodynamic (MHD) turbulence with
rotation, no realistic model for dynamo action currently exists. D5S utilises two recent significant breakthroughs to construct
new models for magnetic field generation in the sun and other solar-type stars. The first of these involves an entirely new
approach termed Direct Statistical Simulation (DSS) (developed by the PI), where the statistics of the astrophysical flows are
solved directly (enabling the construction of more realistic models). This approach is coupled to a breakthrough (recently
published by the PI in Nature) in our understanding of the physics of MHD turbulence at the extreme parameters relevant to
solar interiors. D5S also uses the methodology of DSS to provide statistical subgrid models for Direct Numerical Simulation
(DNS). This will increase the utility, fidelity and predictability of such models for solar magnetic activity. Either of these new
approaches, taken in isolation, would lead to significant progress in our understanding of magnetic field generation in stars.
Taken together, as in this proposal, they will provide a paradigm shift in our theories for solar magnetic activity.
Summary
This proposal (D5S) addresses a key problem of astrophysics – the origin of magnetic activity in the sun and solar-type
stars. This is a problem not only of outstanding theoretical importance but also significant practical impact – solar activity has
major terrestrial consequences. An increase in activity can lead to an increase in the number and violence of solar flares and
coronal mass ejections, with profound consequences for our terrestrial environment, causing disruption to satellites and
power. Predictions of magnetic activity are highly desired by government and industry groups alike. A deep understanding of
the mechanisms leading to solar magnetic activity is required. The variable magnetic field is generated by a dynamo in the
solar interior. Though this mechanism is known to involve the interaction of magnetohydrodynamic (MHD) turbulence with
rotation, no realistic model for dynamo action currently exists. D5S utilises two recent significant breakthroughs to construct
new models for magnetic field generation in the sun and other solar-type stars. The first of these involves an entirely new
approach termed Direct Statistical Simulation (DSS) (developed by the PI), where the statistics of the astrophysical flows are
solved directly (enabling the construction of more realistic models). This approach is coupled to a breakthrough (recently
published by the PI in Nature) in our understanding of the physics of MHD turbulence at the extreme parameters relevant to
solar interiors. D5S also uses the methodology of DSS to provide statistical subgrid models for Direct Numerical Simulation
(DNS). This will increase the utility, fidelity and predictability of such models for solar magnetic activity. Either of these new
approaches, taken in isolation, would lead to significant progress in our understanding of magnetic field generation in stars.
Taken together, as in this proposal, they will provide a paradigm shift in our theories for solar magnetic activity.
Max ERC Funding
2 499 899 €
Duration
Start date: 2018-10-01, End date: 2023-09-30
Project acronym DARK
Project Dark Matters
Researcher (PI) Joseph Ivor Silk
Host Institution (HI) UNIVERSITE PIERRE ET MARIE CURIE - PARIS 6
Call Details Advanced Grant (AdG), PE9, ERC-2010-AdG_20100224
Summary This interdisciplinary proposal spans theoretical astrophysics and particle physics by addressing the need to provide astrophysical expertise to the particle astrophysics community in the area of dark matter and dark energy research. A new dialogue will be developed via collaborations involving expertise in astronomy, statistics and particle physics that centre on fundamental aspects of the nature of the contents of the universe. Theoretical predictions will be refined to pursue the quest for dark matter using novel experiments designed to detect the direct signatures of dark matter in our galactic halo via scattering and indirect via annihilations into high energy particles and photons. Dark matter and dark energy will be studied by cosmic microwave background temperature fluctuations and structure formation constraints. The former probe is contaminated by inadequately understood foregrounds that will be examined to extract clues to new physics in the very early universe, an especially timely research frontier in view of the anticipated data from the Planck satellite. The latter is rendered difficult by the highly complex interface of star and galaxy formation. This will be studied by emphasizing development of feedback prescriptions, an ingredient that plays a central role in the current paradigm for galaxy formation and complements ultradeep searches with the new generation of telescopes. The overall goal, namely to leverage via theory on the unprecedented experimental efforts that are underway to address dark sector issues in the emerging field of particle astrophysics, is achievable at relatively modest cost.
Summary
This interdisciplinary proposal spans theoretical astrophysics and particle physics by addressing the need to provide astrophysical expertise to the particle astrophysics community in the area of dark matter and dark energy research. A new dialogue will be developed via collaborations involving expertise in astronomy, statistics and particle physics that centre on fundamental aspects of the nature of the contents of the universe. Theoretical predictions will be refined to pursue the quest for dark matter using novel experiments designed to detect the direct signatures of dark matter in our galactic halo via scattering and indirect via annihilations into high energy particles and photons. Dark matter and dark energy will be studied by cosmic microwave background temperature fluctuations and structure formation constraints. The former probe is contaminated by inadequately understood foregrounds that will be examined to extract clues to new physics in the very early universe, an especially timely research frontier in view of the anticipated data from the Planck satellite. The latter is rendered difficult by the highly complex interface of star and galaxy formation. This will be studied by emphasizing development of feedback prescriptions, an ingredient that plays a central role in the current paradigm for galaxy formation and complements ultradeep searches with the new generation of telescopes. The overall goal, namely to leverage via theory on the unprecedented experimental efforts that are underway to address dark sector issues in the emerging field of particle astrophysics, is achievable at relatively modest cost.
Max ERC Funding
2 499 990 €
Duration
Start date: 2011-06-01, End date: 2017-05-31
Project acronym DARKLIGHT
Project ILLUMINATING DARK ENERGY WITH THE NEXT GENERATION OF COSMOLOGICAL REDSHIFT SURVEYS
Researcher (PI) Luigi Guzzo
Host Institution (HI) UNIVERSITA DEGLI STUDI DI MILANO
Call Details Advanced Grant (AdG), PE9, ERC-2011-ADG_20110209
Summary Galaxy redshift surveys have been central in establishing the current successful cosmological model. Reconstructing the large-scale distribution of galaxies in space and time, they provide us with a unique probe of the basic constituents of the Universe, their evolution and the background fundamental physics. A new generation of even larger surveys is planned for the starting decade, with the aim of solving the remaining mysteries of the standard model using high-precision measurements of galaxy clustering. These entail the nature of the “dark sector” and in particular the origin of the accelerated cosmic expansion. While data accumulation already started, the needed analysis capabilities to reach the required percent levels in both accuracy and precision are not ready yet.
I propose to establish a focused research group to develop these tools and optimally analyze the new data, while being directly involved in their collection. New techniques as redshift-space distortions and well-known but still debated probes as galaxy clusters will be refined to a new level. They will be combined with more standard methods as baryonic acoustic oscillations and external data as CMB anisotropies. Performances will be validated on mock samples from large numerical simulations and then applied to state-of-the-art data with enhanced control over systematic errors to obtain the best achievable measurements.
These new capabilities will be decisive in enabling ongoing and future surveys to tackle the key open problems in cosmology: What is the nature of dark energy? Is it produced by an evolving scalar field? Or does it rather require a modification of the laws of gravity? How does it relate to dark matter? What is the role of neutrinos? The answer to these questions may well revolutionize our view of physics.
Summary
Galaxy redshift surveys have been central in establishing the current successful cosmological model. Reconstructing the large-scale distribution of galaxies in space and time, they provide us with a unique probe of the basic constituents of the Universe, their evolution and the background fundamental physics. A new generation of even larger surveys is planned for the starting decade, with the aim of solving the remaining mysteries of the standard model using high-precision measurements of galaxy clustering. These entail the nature of the “dark sector” and in particular the origin of the accelerated cosmic expansion. While data accumulation already started, the needed analysis capabilities to reach the required percent levels in both accuracy and precision are not ready yet.
I propose to establish a focused research group to develop these tools and optimally analyze the new data, while being directly involved in their collection. New techniques as redshift-space distortions and well-known but still debated probes as galaxy clusters will be refined to a new level. They will be combined with more standard methods as baryonic acoustic oscillations and external data as CMB anisotropies. Performances will be validated on mock samples from large numerical simulations and then applied to state-of-the-art data with enhanced control over systematic errors to obtain the best achievable measurements.
These new capabilities will be decisive in enabling ongoing and future surveys to tackle the key open problems in cosmology: What is the nature of dark energy? Is it produced by an evolving scalar field? Or does it rather require a modification of the laws of gravity? How does it relate to dark matter? What is the role of neutrinos? The answer to these questions may well revolutionize our view of physics.
Max ERC Funding
1 723 600 €
Duration
Start date: 2012-05-01, End date: 2017-10-31
Project acronym DCENSY
Project Doping, Charge Transfer and Energy Flow in Hybrid Nanoparticle Systems
Researcher (PI) Uri Banin
Host Institution (HI) THE HEBREW UNIVERSITY OF JERUSALEM
Call Details Advanced Grant (AdG), PE4, ERC-2009-AdG
Summary We target a frontier in nanocrystal science of combining disparate materials into a single hybrid nanosystem. This offers an intriguing route to engineer nanomaterials with multiple functionalities in ways that are not accessible in bulk materials or in molecules. Such control of novel material combinations on a single nanoparticle or in a super-structure of assembled nanoparticles, presents alongside with the synthesis challenges, fundamental questions concerning the physical attributes of nanoscale systems. My goals are to create new highly controlled hybrid nanoparticle systems, focusing on combinations of semiconductors and metals, and to decipher the fundamental principles governing doping in nanoparticles and charge and energy transfer processes among components of the hybrid systems. The research addresses several key challenges: First, in synthesis, combining disparate material components into one hybrid nanoparticle system. Second, in self assembly, organizing a combination of semiconductor (SC) and metal nanoparticle building blocks into hybrid systems with controlled architecture. Third in fundamental physico-chemical questions pertaining to the unique attributes of the hybrid systems, constituting a key component of the research. A first aspect concerns doping of SC nanoparticles with metal atoms. A second aspect concerns light-induced charge transfer between the SC part and metal parts of the hybrid constructs. A third related aspect concerns energy transfer processes between the SC and metal components and the interplay between near-field enhancement and fluorescence quenching effects. Due to the new properties, significant impact on nanocrystal applications in solar energy harvesting, biological tagging, sensing, optics and electropotics is expected.
Summary
We target a frontier in nanocrystal science of combining disparate materials into a single hybrid nanosystem. This offers an intriguing route to engineer nanomaterials with multiple functionalities in ways that are not accessible in bulk materials or in molecules. Such control of novel material combinations on a single nanoparticle or in a super-structure of assembled nanoparticles, presents alongside with the synthesis challenges, fundamental questions concerning the physical attributes of nanoscale systems. My goals are to create new highly controlled hybrid nanoparticle systems, focusing on combinations of semiconductors and metals, and to decipher the fundamental principles governing doping in nanoparticles and charge and energy transfer processes among components of the hybrid systems. The research addresses several key challenges: First, in synthesis, combining disparate material components into one hybrid nanoparticle system. Second, in self assembly, organizing a combination of semiconductor (SC) and metal nanoparticle building blocks into hybrid systems with controlled architecture. Third in fundamental physico-chemical questions pertaining to the unique attributes of the hybrid systems, constituting a key component of the research. A first aspect concerns doping of SC nanoparticles with metal atoms. A second aspect concerns light-induced charge transfer between the SC part and metal parts of the hybrid constructs. A third related aspect concerns energy transfer processes between the SC and metal components and the interplay between near-field enhancement and fluorescence quenching effects. Due to the new properties, significant impact on nanocrystal applications in solar energy harvesting, biological tagging, sensing, optics and electropotics is expected.
Max ERC Funding
2 499 000 €
Duration
Start date: 2010-06-01, End date: 2015-05-31
Project acronym DiluteParaWater
Project Long-Lived Nuclear Magnetization in Dilute Para-Water
Researcher (PI) Geoffrey Bodenhausen
Host Institution (HI) ECOLE NORMALE SUPERIEURE
Call Details Advanced Grant (AdG), PE4, ERC-2013-ADG
Summary The magnetization of hydrogen nuclei in H2O constitutes the basis of most applications of magnetic resonance imaging (MRI.) Only ortho-water, where the two proton spins are in states that are symmetric with respect to permutation, features NMR-allowed transitions. Para-water is analogous to para-hydrogen, where the two proton spins are anti-symmetric with respect to permutation. The objective of this proposal is to render para-H2O accessible to observation. Several strategies will be developed for its preparation and observation in solids, liquids and gas phase, with yields up to 33%. When diluted in acetonitrile at room temperature, we found that Tortho(H2O) = 6 s. Based on experiments on H2C groups where Tpara/Tortho > 37, we conservatively estimate that Tpara/Tortho > 10 for H2O, so that we expect Tpara = 60 s. Dilution in aprotic solvents inhibits the exchange of protons and extends the lifetimes t(H2O) of water molecules from ca. 1 ms in pure water to 10 s and beyond, so that proton exchange does not hamper the use para-water. The ratio Tpara/Tortho of H2O depends on temperature, viscosity, paramagnetic agents, etc., which affect intra- and inter-molecular dipole-dipole interactions, chemical shift anisotropy, and spin rotation. In cases where proton exchange significantly shortens the lifetime of para-H2O, we shall prepare and observe para-ethanol and aqueous solutions of para-glycine, which cannot suffer from proton exchange, and allow similar perspectives as para-water. In conventional MRI, contrast stems mostly from spatial variations of T1 and T2. By monitoring the ratio Tpara/Tortho as a function of spatial coordinates, it will be possible to obtain a novel type of contrast. In suitable phantoms and porous media, para-water will allow us to characterize slow transport phenomena such as flow, diffusion, and electrophoretic mobility. The study of transport phenomena will become possible over longer time intervals, lower velocities or greater distances.
Summary
The magnetization of hydrogen nuclei in H2O constitutes the basis of most applications of magnetic resonance imaging (MRI.) Only ortho-water, where the two proton spins are in states that are symmetric with respect to permutation, features NMR-allowed transitions. Para-water is analogous to para-hydrogen, where the two proton spins are anti-symmetric with respect to permutation. The objective of this proposal is to render para-H2O accessible to observation. Several strategies will be developed for its preparation and observation in solids, liquids and gas phase, with yields up to 33%. When diluted in acetonitrile at room temperature, we found that Tortho(H2O) = 6 s. Based on experiments on H2C groups where Tpara/Tortho > 37, we conservatively estimate that Tpara/Tortho > 10 for H2O, so that we expect Tpara = 60 s. Dilution in aprotic solvents inhibits the exchange of protons and extends the lifetimes t(H2O) of water molecules from ca. 1 ms in pure water to 10 s and beyond, so that proton exchange does not hamper the use para-water. The ratio Tpara/Tortho of H2O depends on temperature, viscosity, paramagnetic agents, etc., which affect intra- and inter-molecular dipole-dipole interactions, chemical shift anisotropy, and spin rotation. In cases where proton exchange significantly shortens the lifetime of para-H2O, we shall prepare and observe para-ethanol and aqueous solutions of para-glycine, which cannot suffer from proton exchange, and allow similar perspectives as para-water. In conventional MRI, contrast stems mostly from spatial variations of T1 and T2. By monitoring the ratio Tpara/Tortho as a function of spatial coordinates, it will be possible to obtain a novel type of contrast. In suitable phantoms and porous media, para-water will allow us to characterize slow transport phenomena such as flow, diffusion, and electrophoretic mobility. The study of transport phenomena will become possible over longer time intervals, lower velocities or greater distances.
Max ERC Funding
2 500 000 €
Duration
Start date: 2014-01-01, End date: 2018-12-31
Project acronym DISCSIM
Project Hydrodynamical simulations of protoplanetary discs in the era of ALMA imaging
Researcher (PI) Catherine Clarke
Host Institution (HI) THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
Call Details Advanced Grant (AdG), PE9, ERC-2013-ADG
Summary "This is a proposal for an ambitious programme of state of the art hydrodynamical simulations, designed to answer some key questions about the role of disc self-gravity in planet formation. The programme is also designed so as to maximize the synergy with the new observational constraints from high resolution imaging data from the Atacama Large Millimetre Array that will become available over the timescale of the grant. The five year programme should provide definitive answers about whether planet formation is able to get going during the early, self-gravitating phase of disc evolution and how, if so, it would affect the further evolution of the disc. The topic of gravitational disc fragmentation as a route to planet formation is currently in a state of crisis, with recent simulations undermining what had become a consensus view on the subject. A dedicated and carefully constructed approach, as detailed here, is required to solve this problem."
Summary
"This is a proposal for an ambitious programme of state of the art hydrodynamical simulations, designed to answer some key questions about the role of disc self-gravity in planet formation. The programme is also designed so as to maximize the synergy with the new observational constraints from high resolution imaging data from the Atacama Large Millimetre Array that will become available over the timescale of the grant. The five year programme should provide definitive answers about whether planet formation is able to get going during the early, self-gravitating phase of disc evolution and how, if so, it would affect the further evolution of the disc. The topic of gravitational disc fragmentation as a route to planet formation is currently in a state of crisis, with recent simulations undermining what had become a consensus view on the subject. A dedicated and carefully constructed approach, as detailed here, is required to solve this problem."
Max ERC Funding
1 892 844 €
Duration
Start date: 2014-02-01, End date: 2019-01-31
Project acronym DISKtoHALO
Project From the accretion disk to the cluster halo: the multi-scale physics of black hole feedback
Researcher (PI) Christopher REYNOLDS
Host Institution (HI) THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
Call Details Advanced Grant (AdG), PE9, ERC-2018-ADG
Summary It is firmly established that supermassive black holes (SMBHs) have a profound influence on the evolution of galaxies and galaxy groups/clusters. Yet, almost 20 years after this realization, fundamental questions remain. What determines the efficiency with which an active galactic nucleus (AGN) couples to its surroundings? Why does AGN feedback appear to be ineffective in low-mass galaxies? In maintenance-mode feedback, how does the AGN regulate to closely balance cooling? How does the nature of AGN feedback change as we consider higher redshifts and push back to the epoch of the first galaxies? AGN feedback is a truly multi-scale phenomenon. Observations show that AGN have an energetic impact on galactic-, group-, and cluster-halo scales. Yet the efficiency with which an accreting SMBH releases energy, and the partitioning of that energy into radiation, winds, and relativistic jets, is dictated by complex processes in the accretion disk on AU scales, 10^10 times smaller than the halo. Furthermore, especially in massive systems where feedback proceeds via the heating of a hot circumgalactic or intracluster medium (CGM/ICM), the relevant microphysics of the hot baryons is unclear, requiring an understanding of plasma instabilities on 10^-9pc scales. We propose a set of projects that explore the multiscale physics of AGN feedback. Magnetohydrodynamic models of accretion disks will be constructed to study the AGN radiation/winds/jets and calibrate observable proxies of SMBH mass and accretion rate. We will use the machinery of plasma physics to characterize the CGM/ICM microphysics relevant to the thermalization of AGN-injected energy. Finally, we will produce new galaxy-, group- and cluster-scale models incorporating the new microphysical prescriptions and AGN models. Our new theoretical understanding of AGN feedback as a function of halo mass, environment, and cosmic time is essential for interpreting the torrent of data from current and future observatories
Summary
It is firmly established that supermassive black holes (SMBHs) have a profound influence on the evolution of galaxies and galaxy groups/clusters. Yet, almost 20 years after this realization, fundamental questions remain. What determines the efficiency with which an active galactic nucleus (AGN) couples to its surroundings? Why does AGN feedback appear to be ineffective in low-mass galaxies? In maintenance-mode feedback, how does the AGN regulate to closely balance cooling? How does the nature of AGN feedback change as we consider higher redshifts and push back to the epoch of the first galaxies? AGN feedback is a truly multi-scale phenomenon. Observations show that AGN have an energetic impact on galactic-, group-, and cluster-halo scales. Yet the efficiency with which an accreting SMBH releases energy, and the partitioning of that energy into radiation, winds, and relativistic jets, is dictated by complex processes in the accretion disk on AU scales, 10^10 times smaller than the halo. Furthermore, especially in massive systems where feedback proceeds via the heating of a hot circumgalactic or intracluster medium (CGM/ICM), the relevant microphysics of the hot baryons is unclear, requiring an understanding of plasma instabilities on 10^-9pc scales. We propose a set of projects that explore the multiscale physics of AGN feedback. Magnetohydrodynamic models of accretion disks will be constructed to study the AGN radiation/winds/jets and calibrate observable proxies of SMBH mass and accretion rate. We will use the machinery of plasma physics to characterize the CGM/ICM microphysics relevant to the thermalization of AGN-injected energy. Finally, we will produce new galaxy-, group- and cluster-scale models incorporating the new microphysical prescriptions and AGN models. Our new theoretical understanding of AGN feedback as a function of halo mass, environment, and cosmic time is essential for interpreting the torrent of data from current and future observatories
Max ERC Funding
2 489 918 €
Duration
Start date: 2019-10-01, End date: 2024-09-30
Project acronym DM
Project Dirac Materials
Researcher (PI) Alexander Balatsky
Host Institution (HI) KUNGLIGA TEKNISKA HOEGSKOLAN
Call Details Advanced Grant (AdG), PE3, ERC-2012-ADG_20120216
Summary "The elegant Dirac equation, describing the linear dispersion (energy/momentum) relation of electrons at relativistic speeds, has profound consequences such as the prediction of antiparticles, reflection less tunneling (Klein paradox) and others. Recent discovery of graphene and topological insulators (TI) highlights the scientific importance and technological promise of materials with “relativistic Dirac dispersion"" of electrons for functional materials and device applications with novel functionalities. One might use term ‘Dirac materials’ to encompass a subset of (materials) systems in which the low energy phase space for fermion excitations is reduced compared to conventional band structure predictions (i.e. point or lines of nodes vs. full Fermi Surface).
Dirac materials are characterized by universal low energy properties due to presence of the nodal excitations. It is this reduction of phase space due to additional symmetries that can be turned on and off that opens a new door to functionality of Dirac materials.
We propose to use the sensitivity of nodes in the electron spectrum of Dirac materials to induce controlled modifications of the Dirac points/lines via band structure engineering in artificial structures and via inelastic scattering processes with controlled doping. Proposed research will expand our theoretical understanding and guide design of materials and engineered geometries that allow tunable energy profiles of Dirac carriers."
Summary
"The elegant Dirac equation, describing the linear dispersion (energy/momentum) relation of electrons at relativistic speeds, has profound consequences such as the prediction of antiparticles, reflection less tunneling (Klein paradox) and others. Recent discovery of graphene and topological insulators (TI) highlights the scientific importance and technological promise of materials with “relativistic Dirac dispersion"" of electrons for functional materials and device applications with novel functionalities. One might use term ‘Dirac materials’ to encompass a subset of (materials) systems in which the low energy phase space for fermion excitations is reduced compared to conventional band structure predictions (i.e. point or lines of nodes vs. full Fermi Surface).
Dirac materials are characterized by universal low energy properties due to presence of the nodal excitations. It is this reduction of phase space due to additional symmetries that can be turned on and off that opens a new door to functionality of Dirac materials.
We propose to use the sensitivity of nodes in the electron spectrum of Dirac materials to induce controlled modifications of the Dirac points/lines via band structure engineering in artificial structures and via inelastic scattering processes with controlled doping. Proposed research will expand our theoretical understanding and guide design of materials and engineered geometries that allow tunable energy profiles of Dirac carriers."
Max ERC Funding
1 700 000 €
Duration
Start date: 2013-04-01, End date: 2018-03-31
Project acronym DMIDAS
Project Astrophysical constraints on the identity of the dark matter
Researcher (PI) Carlos Silvestre FRENK
Host Institution (HI) UNIVERSITY OF DURHAM
Call Details Advanced Grant (AdG), PE9, ERC-2017-ADG
Summary The identity of the dark matter is a fundamental problem in Physics whose solution will have major implications for cosmology, astronomy and particle physics. There is compelling evidence that the dark matter consists of elementary particles created shortly after the Big Bang, but searches for them in the laboratory and from astrophysical sources have proved inconclusive. The currently favoured candidate is cold dark matter or CDM. This forms the basis of the standard model of cosmology, LCDM, whose predictions, dating back to the 1980s, turned out to agree remarkably well with observations covering a staggering range of epochs and scales, from the temperature structure of the cosmic microwave background radiation to the large-scale pattern of galaxy clustering. Yet, this agreement is not exclusive to CDM: models based on other types of particles -- warm, self-interacting or asymmetric, for example -- agree equally well with these data but differ on scales smaller than individual bright galaxies. These are the scales targeted in this application in which we propose a comprehensive investigation of small-scale structure, with the aim of testing dark matter candidates, by focusing on three key astrophysical diagnostics: strong gravitational lensing, dwarf galaxies and stellar halos. We propose a joint theoretical and observational programme exploiting three major developments: SWIFT, a new code developed at Durham that will enable cosmological hydrodynamics simulations an order of magnitude larger than is possible today; SuperBIT, an innovative balloon-borne wide-field imaging telescope that will collect gravitational lensing data for hundreds of galaxy clusters; and DESI, a spectro-photometric survey that will acquire 10 times more spectra of stars in the Milky Way than previous surveys. The particle models that we will consider have predictive power and are disprovable. Our programme has the potential to rule out many dark matter particle candidates, including CDM.
Summary
The identity of the dark matter is a fundamental problem in Physics whose solution will have major implications for cosmology, astronomy and particle physics. There is compelling evidence that the dark matter consists of elementary particles created shortly after the Big Bang, but searches for them in the laboratory and from astrophysical sources have proved inconclusive. The currently favoured candidate is cold dark matter or CDM. This forms the basis of the standard model of cosmology, LCDM, whose predictions, dating back to the 1980s, turned out to agree remarkably well with observations covering a staggering range of epochs and scales, from the temperature structure of the cosmic microwave background radiation to the large-scale pattern of galaxy clustering. Yet, this agreement is not exclusive to CDM: models based on other types of particles -- warm, self-interacting or asymmetric, for example -- agree equally well with these data but differ on scales smaller than individual bright galaxies. These are the scales targeted in this application in which we propose a comprehensive investigation of small-scale structure, with the aim of testing dark matter candidates, by focusing on three key astrophysical diagnostics: strong gravitational lensing, dwarf galaxies and stellar halos. We propose a joint theoretical and observational programme exploiting three major developments: SWIFT, a new code developed at Durham that will enable cosmological hydrodynamics simulations an order of magnitude larger than is possible today; SuperBIT, an innovative balloon-borne wide-field imaging telescope that will collect gravitational lensing data for hundreds of galaxy clusters; and DESI, a spectro-photometric survey that will acquire 10 times more spectra of stars in the Milky Way than previous surveys. The particle models that we will consider have predictive power and are disprovable. Our programme has the potential to rule out many dark matter particle candidates, including CDM.
Max ERC Funding
2 493 439 €
Duration
Start date: 2018-10-01, End date: 2023-09-30
