Project acronym 1D-Engine
Project 1D-electrons coupled to dissipation: a novel approach for understanding and engineering superconducting materials and devices
Researcher (PI) Adrian KANTIAN
Host Institution (HI) UPPSALA UNIVERSITET
Call Details Starting Grant (StG), PE3, ERC-2017-STG
Summary Correlated electrons are at the forefront of condensed matter theory. Interacting quasi-1D electrons have seen vast progress in analytical and numerical theory, and thus in fundamental understanding and quantitative prediction. Yet, in the 1D limit fluctuations preclude important technological use, particularly of superconductors. In contrast, high-Tc superconductors in 2D/3D are not precluded by fluctuations, but lack a fundamental theory, making prediction and engineering of their properties, a major goal in physics, very difficult. This project aims to combine the advantages of both areas by making major progress in the theory of quasi-1D electrons coupled to an electron bath, in part building on recent breakthroughs (with the PIs extensive involvement) in simulating 1D and 2D electrons with parallelized density matrix renormalization group (pDMRG) numerics. Such theory will fundamentally advance the study of open electron systems, and show how to use 1D materials as elements of new superconducting (SC) devices and materials: 1) It will enable a new state of matter, 1D electrons with true SC order. Fluctuations from the electronic liquid, such as graphene, could also enable nanoscale wires to appear SC at high temperatures. 2) A new approach for the deliberate engineering of a high-Tc superconductor. In 1D, how electrons pair by repulsive interactions is understood and can be predicted. Stabilization by reservoir - formed by a parallel array of many such 1D systems - offers a superconductor for which all factors setting Tc are known and can be optimized. 3) Many existing superconductors with repulsive electron pairing, all presently not understood, can be cast as 1D electrons coupled to a bath. Developing chain-DMFT theory based on pDMRG will allow these materials SC properties to be simulated and understood for the first time. 4) The insights gained will be translated to 2D superconductors to study how they could be enhanced by contact with electronic liquids.
Summary
Correlated electrons are at the forefront of condensed matter theory. Interacting quasi-1D electrons have seen vast progress in analytical and numerical theory, and thus in fundamental understanding and quantitative prediction. Yet, in the 1D limit fluctuations preclude important technological use, particularly of superconductors. In contrast, high-Tc superconductors in 2D/3D are not precluded by fluctuations, but lack a fundamental theory, making prediction and engineering of their properties, a major goal in physics, very difficult. This project aims to combine the advantages of both areas by making major progress in the theory of quasi-1D electrons coupled to an electron bath, in part building on recent breakthroughs (with the PIs extensive involvement) in simulating 1D and 2D electrons with parallelized density matrix renormalization group (pDMRG) numerics. Such theory will fundamentally advance the study of open electron systems, and show how to use 1D materials as elements of new superconducting (SC) devices and materials: 1) It will enable a new state of matter, 1D electrons with true SC order. Fluctuations from the electronic liquid, such as graphene, could also enable nanoscale wires to appear SC at high temperatures. 2) A new approach for the deliberate engineering of a high-Tc superconductor. In 1D, how electrons pair by repulsive interactions is understood and can be predicted. Stabilization by reservoir - formed by a parallel array of many such 1D systems - offers a superconductor for which all factors setting Tc are known and can be optimized. 3) Many existing superconductors with repulsive electron pairing, all presently not understood, can be cast as 1D electrons coupled to a bath. Developing chain-DMFT theory based on pDMRG will allow these materials SC properties to be simulated and understood for the first time. 4) The insights gained will be translated to 2D superconductors to study how they could be enhanced by contact with electronic liquids.
Max ERC Funding
1 491 013 €
Duration
Start date: 2018-10-01, End date: 2023-09-30
Project acronym BUCOPHSYS
Project Bottom-up hybrid control and planning synthesis with application to multi-robot multi-human coordination
Researcher (PI) DIMOS Dimarogonas
Host Institution (HI) KUNGLIGA TEKNISKA HOEGSKOLAN
Call Details Starting Grant (StG), PE7, ERC-2014-STG
Summary Current control applications necessitate the treatment of systems with multiple interconnected components, rather than the traditional single component paradigm that has been studied extensively. The individual subsystems may need to fulfil different and possibly conflicting specifications in a real-time manner. At the same time, they may need to fulfill coupled constraints that are defined as relations between their states. Towards this end, the need for methods for decentralized control at the continuous level and planning at the task level becomes apparent. We aim here towards unification of these two complementary approaches. Existing solutions rely on a top down centralized approach. We instead consider here a decentralized, bottom-up solution to the problem. The approach relies on three layers of interaction. In the first layer, agents aim at coordinating in order to fulfil their coupled constraints with limited communication exchange of their state information and design of appropriate feedback controllers; in the second layer, agents coordinate in order to mutually satisfy their discrete tasks through exchange of the corresponding plans in the form of automata; in the third and most challenging layer, the communication exchange for coordination now includes both continuous state and discrete plan/abstraction information. The results will be demonstrated in a scenario involving multiple (possibly human) users and multiple robots.
The unification will yield a completely decentralized system, in which the bottom up approach to define tasks, the consideration of coupled constraints and their combination towards distributed hybrid control and planning in a coordinated fashion require for
new ways of thinking and approaches to analysis and constitute the proposal a beyond the SoA and groundbreaking approach to the fields of control and computer science.
Summary
Current control applications necessitate the treatment of systems with multiple interconnected components, rather than the traditional single component paradigm that has been studied extensively. The individual subsystems may need to fulfil different and possibly conflicting specifications in a real-time manner. At the same time, they may need to fulfill coupled constraints that are defined as relations between their states. Towards this end, the need for methods for decentralized control at the continuous level and planning at the task level becomes apparent. We aim here towards unification of these two complementary approaches. Existing solutions rely on a top down centralized approach. We instead consider here a decentralized, bottom-up solution to the problem. The approach relies on three layers of interaction. In the first layer, agents aim at coordinating in order to fulfil their coupled constraints with limited communication exchange of their state information and design of appropriate feedback controllers; in the second layer, agents coordinate in order to mutually satisfy their discrete tasks through exchange of the corresponding plans in the form of automata; in the third and most challenging layer, the communication exchange for coordination now includes both continuous state and discrete plan/abstraction information. The results will be demonstrated in a scenario involving multiple (possibly human) users and multiple robots.
The unification will yield a completely decentralized system, in which the bottom up approach to define tasks, the consideration of coupled constraints and their combination towards distributed hybrid control and planning in a coordinated fashion require for
new ways of thinking and approaches to analysis and constitute the proposal a beyond the SoA and groundbreaking approach to the fields of control and computer science.
Max ERC Funding
1 498 729 €
Duration
Start date: 2015-03-01, End date: 2020-02-29
Project acronym CurvedSusy
Project Dynamics of Supersymmetry in Curved Space
Researcher (PI) Guido Festuccia
Host Institution (HI) UPPSALA UNIVERSITET
Call Details Starting Grant (StG), PE2, ERC-2014-STG
Summary Quantum field theory provides a theoretical framework to explain quantitatively natural phenomena as diverse as the fluctuations in the cosmic microwave background, superconductivity, and elementary particle interactions in colliders. Even if we use quantum field theories in different settings, their structure and dynamics are still largely mysterious. Weakly coupled systems can be studied perturbatively, however many natural phenomena are characterized by strong self-interactions (e.g. high T superconductors, nuclear forces) and their analysis requires going beyond perturbation theory. Supersymmetric field theories are very interesting in this respect because they can be studied exactly even at strong coupling and their dynamics displays phenomena like confinement or the breaking of chiral symmetries that occur in nature and are very difficult to study analytically.
Recently it was realized that many interesting insights on the dynamics of supersymmetric field theories can be obtained by placing these theories in curved space preserving supersymmetry. These advances have opened new research avenues but also left many important questions unanswered. The aim of our research programme will be to clarify the dynamics of supersymmetric field theories in curved space and use this knowledge to establish new exact results for strongly coupled supersymmetric gauge theories. The novelty of our approach resides in the systematic use of the interplay between the physical properties of a supersymmetric theory and the geometrical properties of the space-time it lives in. The analytical results we will obtain, while derived for very symmetric theories, can be used as a guide in understanding the dynamics of many physical systems. Besides providing new tools to address the dynamics of quantum field theory at strong coupling this line of investigation could lead to new connections between Physics and Mathematics.
Summary
Quantum field theory provides a theoretical framework to explain quantitatively natural phenomena as diverse as the fluctuations in the cosmic microwave background, superconductivity, and elementary particle interactions in colliders. Even if we use quantum field theories in different settings, their structure and dynamics are still largely mysterious. Weakly coupled systems can be studied perturbatively, however many natural phenomena are characterized by strong self-interactions (e.g. high T superconductors, nuclear forces) and their analysis requires going beyond perturbation theory. Supersymmetric field theories are very interesting in this respect because they can be studied exactly even at strong coupling and their dynamics displays phenomena like confinement or the breaking of chiral symmetries that occur in nature and are very difficult to study analytically.
Recently it was realized that many interesting insights on the dynamics of supersymmetric field theories can be obtained by placing these theories in curved space preserving supersymmetry. These advances have opened new research avenues but also left many important questions unanswered. The aim of our research programme will be to clarify the dynamics of supersymmetric field theories in curved space and use this knowledge to establish new exact results for strongly coupled supersymmetric gauge theories. The novelty of our approach resides in the systematic use of the interplay between the physical properties of a supersymmetric theory and the geometrical properties of the space-time it lives in. The analytical results we will obtain, while derived for very symmetric theories, can be used as a guide in understanding the dynamics of many physical systems. Besides providing new tools to address the dynamics of quantum field theory at strong coupling this line of investigation could lead to new connections between Physics and Mathematics.
Max ERC Funding
1 145 879 €
Duration
Start date: 2015-09-01, End date: 2020-08-31
Project acronym D-SynMA
Project Distributed Synthesis: from Single to Multiple Agents
Researcher (PI) Nir PITERMAN
Host Institution (HI) GOETEBORGS UNIVERSITET
Call Details Consolidator Grant (CoG), PE6, ERC-2017-COG
Summary Computing is changing from living on our desktops and in dedicated devices to being everywhere. In phones, sensors, appliances, and robots – computers (from now on devices) are everywhere and affecting all aspects of our lives. The techniques to make them safe and reliable are investigated and are starting to emerge and consolidate. However, these techniques enable devices to work in isolation or co-exist. We currently do not have techniques that enable development of real autonomous collaboration between devices. Such techniques will revolutionize all usage of devices and, as consequence, our lives. Manufacturing, supply chain, transportation, infrastructures, and earth- and space exploration would all transform using techniques that enable development of collaborating devices.
When considering isolated (and co-existing) devices, reactive synthesis – automatic production of plans from high level specification – is emerging as a viable tool for the development of robots and reactive software. This is especially important in the context of safety-critical systems, where assurances are required and systems need to have guarantees on performance. The techniques that are developed today to support robust, assured, reliable, and adaptive devices rely on a major change in focus of reactive synthesis. The revolution of correct-by-construction systems from specifications is occurring and is being pushed forward.
However, to take this approach forward to work also for real collaboration between devices the theoretical frameworks that will enable distributed synthesis are required. Such foundations will enable the correct-by-construction revolution to unleash its potential and allow a multiplicative increase of utility by cooperative computation.
d-SynMA will take distributed synthesis to this new frontier by considering novel interaction and communication concepts that would create an adaptable framework of correct-by-construction application of collaborating devices.
Summary
Computing is changing from living on our desktops and in dedicated devices to being everywhere. In phones, sensors, appliances, and robots – computers (from now on devices) are everywhere and affecting all aspects of our lives. The techniques to make them safe and reliable are investigated and are starting to emerge and consolidate. However, these techniques enable devices to work in isolation or co-exist. We currently do not have techniques that enable development of real autonomous collaboration between devices. Such techniques will revolutionize all usage of devices and, as consequence, our lives. Manufacturing, supply chain, transportation, infrastructures, and earth- and space exploration would all transform using techniques that enable development of collaborating devices.
When considering isolated (and co-existing) devices, reactive synthesis – automatic production of plans from high level specification – is emerging as a viable tool for the development of robots and reactive software. This is especially important in the context of safety-critical systems, where assurances are required and systems need to have guarantees on performance. The techniques that are developed today to support robust, assured, reliable, and adaptive devices rely on a major change in focus of reactive synthesis. The revolution of correct-by-construction systems from specifications is occurring and is being pushed forward.
However, to take this approach forward to work also for real collaboration between devices the theoretical frameworks that will enable distributed synthesis are required. Such foundations will enable the correct-by-construction revolution to unleash its potential and allow a multiplicative increase of utility by cooperative computation.
d-SynMA will take distributed synthesis to this new frontier by considering novel interaction and communication concepts that would create an adaptable framework of correct-by-construction application of collaborating devices.
Max ERC Funding
1 871 272 €
Duration
Start date: 2018-05-01, End date: 2023-04-30
Project acronym DarkComb
Project Dark-Soliton Engineering in Microresonator Frequency Combs
Researcher (PI) Victor TORRES COMPANY
Host Institution (HI) CHALMERS TEKNISKA HOEGSKOLA AB
Call Details Consolidator Grant (CoG), PE7, ERC-2017-COG
Summary The continuing increase in Internet data traffic is pushing the capacity of single-mode fiber to its fundamental limits. Space division multiplexing (SDM) offers the only remaining physical degree of freedom – the space dimension in the transmission channel – to substantially increase the capacity in lightwave communication systems.
The microresonator comb is an emerging technology platform that enables the generation of an optical frequency comb in a micrometer-scale cavity. Its compact size and compatibility with established semiconductor fabrication techniques promises to revolutionize the fields of frequency synthesis and metrology, and create new mass-market applications.
I envision significant scaling advantages in future fiber-optic communications by merging SDM with microresonator frequency combs. One major obstacle to overcome here is the poor conversion efficiency that can be fundamentally obtained using the most stable and broadest combs generated in microresonators today. I propose to look into the generation of dark, as opposed to bright, temporal solitons in linearly coupled microresonators. The goal is to achieve reliable microresonator combs with exceptionally high power conversion efficiency, resulting in optimal characteristics for SDM applications. The scientific and technological possibilities of this achievement promise significant impact beyond the realm of fiber-optic communications.
My broad international experience, unique background in fiber communications, photonic waveguides and ultrafast photonics, the preliminary results of my group and the available infrastructure at my university place me in an outstanding position to pioneer this new direction of research.
Summary
The continuing increase in Internet data traffic is pushing the capacity of single-mode fiber to its fundamental limits. Space division multiplexing (SDM) offers the only remaining physical degree of freedom – the space dimension in the transmission channel – to substantially increase the capacity in lightwave communication systems.
The microresonator comb is an emerging technology platform that enables the generation of an optical frequency comb in a micrometer-scale cavity. Its compact size and compatibility with established semiconductor fabrication techniques promises to revolutionize the fields of frequency synthesis and metrology, and create new mass-market applications.
I envision significant scaling advantages in future fiber-optic communications by merging SDM with microresonator frequency combs. One major obstacle to overcome here is the poor conversion efficiency that can be fundamentally obtained using the most stable and broadest combs generated in microresonators today. I propose to look into the generation of dark, as opposed to bright, temporal solitons in linearly coupled microresonators. The goal is to achieve reliable microresonator combs with exceptionally high power conversion efficiency, resulting in optimal characteristics for SDM applications. The scientific and technological possibilities of this achievement promise significant impact beyond the realm of fiber-optic communications.
My broad international experience, unique background in fiber communications, photonic waveguides and ultrafast photonics, the preliminary results of my group and the available infrastructure at my university place me in an outstanding position to pioneer this new direction of research.
Max ERC Funding
2 259 523 €
Duration
Start date: 2018-05-01, End date: 2023-04-30
Project acronym FUN POLYSTORE
Project FUNctionalized POLYmer electrolytes for energy STORagE
Researcher (PI) Daniel BRANDELL
Host Institution (HI) UPPSALA UNIVERSITET
Call Details Consolidator Grant (CoG), PE5, ERC-2017-COG
Summary Besides the need for large-scale implementation of renewable energy sources, there is an equivalent need for new energy storage solutions. This is not least true for the transport sector, where electric vehicles are expanding rapidly. The rich flora of battery chemistries – today crowned by the Li-ion battery – is likewise expected to expand in upcoming years. Novel types of batteries, “post-lithium ion”, will challenge the Li-ion chemistries by advantages in cost, sustainability, elemental abundance or energy density. This requires significant improvements of the materials, not least regarding the electrolyte. The conventional liquid battery electrolytes pose a problem already for the mature Li-ion chemistries due to safety and cost, but are particularly destructive for future battery types such as Li-metal, organic electrodes, Li-S, Li-O2, Na- or Mg-batteries, where rapid degradation and loss of material are associated with incompatibilities with the electrolytes. In this context, solid state polymer electrolytes (SPEs) could provide a considerable improvement.
The field of solid polymer electrolytes (SPEs) is dominated by polyethers, particularly poly(ethylene oxide) (PEO). This application regards moving out of the established PEO-paradigm and exploring alternative polymer hosts for SPEs, primarily polycarbonates and polyesters. These ‘alternative’ polymers are comparatively easy to work with synthetically, and their possible functionalization is straightforward. The work aims at exploring functionalized alternative polymer host for mechanically robust block-copolymer systems, for alternative cation chemistries (Na, Mg, etc.), for extremely high and low electrochemical potentials, and for unstable and easily dissolved electrode materials (sulfur, organic). Moreover, since the ion transport processes in the host materials are fundamentally different from polyethers, there is a need for investigating the conduction mechanisms using simulations.
Summary
Besides the need for large-scale implementation of renewable energy sources, there is an equivalent need for new energy storage solutions. This is not least true for the transport sector, where electric vehicles are expanding rapidly. The rich flora of battery chemistries – today crowned by the Li-ion battery – is likewise expected to expand in upcoming years. Novel types of batteries, “post-lithium ion”, will challenge the Li-ion chemistries by advantages in cost, sustainability, elemental abundance or energy density. This requires significant improvements of the materials, not least regarding the electrolyte. The conventional liquid battery electrolytes pose a problem already for the mature Li-ion chemistries due to safety and cost, but are particularly destructive for future battery types such as Li-metal, organic electrodes, Li-S, Li-O2, Na- or Mg-batteries, where rapid degradation and loss of material are associated with incompatibilities with the electrolytes. In this context, solid state polymer electrolytes (SPEs) could provide a considerable improvement.
The field of solid polymer electrolytes (SPEs) is dominated by polyethers, particularly poly(ethylene oxide) (PEO). This application regards moving out of the established PEO-paradigm and exploring alternative polymer hosts for SPEs, primarily polycarbonates and polyesters. These ‘alternative’ polymers are comparatively easy to work with synthetically, and their possible functionalization is straightforward. The work aims at exploring functionalized alternative polymer host for mechanically robust block-copolymer systems, for alternative cation chemistries (Na, Mg, etc.), for extremely high and low electrochemical potentials, and for unstable and easily dissolved electrode materials (sulfur, organic). Moreover, since the ion transport processes in the host materials are fundamentally different from polyethers, there is a need for investigating the conduction mechanisms using simulations.
Max ERC Funding
1 950 732 €
Duration
Start date: 2018-09-01, End date: 2023-08-31
Project acronym HIDDeN
Project HIDDeN - Exploring the Hidden Dusty Nuclei of Galaxies
Researcher (PI) Eva Susanne AALTO
Host Institution (HI) CHALMERS TEKNISKA HOEGSKOLA AB
Call Details Advanced Grant (AdG), PE9, ERC-2017-ADG
Summary Luminous infrared galaxies (LIRGs) emit most of their bolometric luminosity in the far-infrared. They are mainly powered by extreme bursts of star formation and/or Active Galactic Nuclei (AGNs; accreting supermassive black holes (SMBHs)) in their centres. LIRGs are the closest examples of rapid evolution in galaxies and a detailed study of LIRGs is critical for our understanding of the cosmic evolution of galaxies and SMBHs. Centres of some LIRGs are deeply obscured and unreachable at optical, IR and even X-ray wavelengths. These hidden nuclei therefore represent a largely unexplored phase of the growth of central regions with their SMBHs. Large growth spurts are suspected to occur when the SMBHs are deeply embedded. Obscured AGNs thus can provide new constraints on the AGN duty cycle, give the full range of environments and astrophysical processes that drive the growth of SMBHs, and help to complete the picture of connections between the host galaxy and SMBH. Many dust embedded AGNs are still to be discovered as studies suggest that a significant fraction of SMBHs may be obscured in the local and more distant Universe.
In the HIDDeN project we use mm and submm observational methods to reach behind the curtain of dust in the most embedded centres of LIRGs, allowing us to undertake ground-breaking studies of heretofore hidden rapid evolutionary phases of nearby galaxy nuclei. HIDDeN takes advantage of emerging opportunities to address the nature of near-field, and redshift z=1-2, obscured AGNs/starbursts and their associated molecular inflows and outflows in the context of their evolution and the starburst-AGN connection. In particular we use the ALMA and NOEMA telescopes, supported by JVLA, LOFAR, HST and future JWST observations, to address four interconnected goals: A. Probing the Dusty Interiors of Compact Obscured Nuclei (CONs), B. The cold winds of change - Molecular Outflows from LIRGs and AGNs, C. The Co-Evolution of Starbursts and AGNs and D. Are there hidden CONs at z=1-2
Summary
Luminous infrared galaxies (LIRGs) emit most of their bolometric luminosity in the far-infrared. They are mainly powered by extreme bursts of star formation and/or Active Galactic Nuclei (AGNs; accreting supermassive black holes (SMBHs)) in their centres. LIRGs are the closest examples of rapid evolution in galaxies and a detailed study of LIRGs is critical for our understanding of the cosmic evolution of galaxies and SMBHs. Centres of some LIRGs are deeply obscured and unreachable at optical, IR and even X-ray wavelengths. These hidden nuclei therefore represent a largely unexplored phase of the growth of central regions with their SMBHs. Large growth spurts are suspected to occur when the SMBHs are deeply embedded. Obscured AGNs thus can provide new constraints on the AGN duty cycle, give the full range of environments and astrophysical processes that drive the growth of SMBHs, and help to complete the picture of connections between the host galaxy and SMBH. Many dust embedded AGNs are still to be discovered as studies suggest that a significant fraction of SMBHs may be obscured in the local and more distant Universe.
In the HIDDeN project we use mm and submm observational methods to reach behind the curtain of dust in the most embedded centres of LIRGs, allowing us to undertake ground-breaking studies of heretofore hidden rapid evolutionary phases of nearby galaxy nuclei. HIDDeN takes advantage of emerging opportunities to address the nature of near-field, and redshift z=1-2, obscured AGNs/starbursts and their associated molecular inflows and outflows in the context of their evolution and the starburst-AGN connection. In particular we use the ALMA and NOEMA telescopes, supported by JVLA, LOFAR, HST and future JWST observations, to address four interconnected goals: A. Probing the Dusty Interiors of Compact Obscured Nuclei (CONs), B. The cold winds of change - Molecular Outflows from LIRGs and AGNs, C. The Co-Evolution of Starbursts and AGNs and D. Are there hidden CONs at z=1-2
Max ERC Funding
2 496 319 €
Duration
Start date: 2018-10-01, End date: 2023-09-30
Project acronym highECS
Project Reining in the upper bound on Earth’s Climate Sensitivities
Researcher (PI) Thorsten MAURITSEN
Host Institution (HI) STOCKHOLMS UNIVERSITET
Call Details Consolidator Grant (CoG), PE10, ERC-2017-COG
Summary One of the greatest recent advances in climate science is that it is now beyond reasonable doubt that human activity is warming the Earth. The next natural question is by how much the Earth will warm for a given emission – a quantity that will be essential to regulating global warming. Yet, the likely range of 1.5-4.5 K for equilibrium climate sensitivity (ECS) for a doubling of the atmospheric CO2 concentration has not been reduced for decades. In particular the risk of ECS being high is concerning, but also represents a scientifically intriguing challenge.
In this project I will conduct unconventional and innovative research designed to limit the upper bound of ECS: I will confront leading hypotheses of extreme cloud feedbacks – the primary potential source of a high ECS – with observations from the full instrumental- and satellite records, and proxies from warm- and cold past climates. I will investigate how ocean- and atmospheric circulations impact cloud feedbacks, and seek the limits for how much past greenhouse warming could have been masked by aerosol cooling.
The highECS project builds on my developments of climate modeling, diagnostics and statistical methods, the strengths of the host institution and developments in national and international projects. The effort is timely in that the World Climate Research Programme (WCRP) has identified uncertainty in ECS as one of the grand challenges of climate science, while the capacity to observe ongoing climate change, key cloud processes, extracting new proxy evidence of past change and computing power is greater than ever before.
If successful in my objective of reining in the upper bound on climate sensitivity this will be a major breakthrough upon a nearly 40-year scientific deadlock and reduce the risk of catastrophic climate change – if not, it will indicate that extreme policy measures may be needed to curb future global warming. Either way, the economic value of knowing is tremendous.
Summary
One of the greatest recent advances in climate science is that it is now beyond reasonable doubt that human activity is warming the Earth. The next natural question is by how much the Earth will warm for a given emission – a quantity that will be essential to regulating global warming. Yet, the likely range of 1.5-4.5 K for equilibrium climate sensitivity (ECS) for a doubling of the atmospheric CO2 concentration has not been reduced for decades. In particular the risk of ECS being high is concerning, but also represents a scientifically intriguing challenge.
In this project I will conduct unconventional and innovative research designed to limit the upper bound of ECS: I will confront leading hypotheses of extreme cloud feedbacks – the primary potential source of a high ECS – with observations from the full instrumental- and satellite records, and proxies from warm- and cold past climates. I will investigate how ocean- and atmospheric circulations impact cloud feedbacks, and seek the limits for how much past greenhouse warming could have been masked by aerosol cooling.
The highECS project builds on my developments of climate modeling, diagnostics and statistical methods, the strengths of the host institution and developments in national and international projects. The effort is timely in that the World Climate Research Programme (WCRP) has identified uncertainty in ECS as one of the grand challenges of climate science, while the capacity to observe ongoing climate change, key cloud processes, extracting new proxy evidence of past change and computing power is greater than ever before.
If successful in my objective of reining in the upper bound on climate sensitivity this will be a major breakthrough upon a nearly 40-year scientific deadlock and reduce the risk of catastrophic climate change – if not, it will indicate that extreme policy measures may be needed to curb future global warming. Either way, the economic value of knowing is tremendous.
Max ERC Funding
1 998 654 €
Duration
Start date: 2018-09-01, End date: 2023-08-31
Project acronym MODULISPACES
Project Topology of moduli spaces of Riemann surfaces
Researcher (PI) Dan PETERSEN
Host Institution (HI) STOCKHOLMS UNIVERSITET
Call Details Starting Grant (StG), PE1, ERC-2017-STG
Summary The proposal describes two main projects. Both of them concern cohomology of moduli spaces of Riemann surfaces, but the aims are rather different.
The first is a natural continuation of my work on tautological rings, which I intend to work on with Qizheng Yin and Mehdi Tavakol. In this project, we will introduce a new perspective on tautological rings, which is that the tautological cohomology of moduli spaces of pointed Riemann surfaces can be described in terms of tautological cohomology of the moduli space M_g, but with twisted coefficients. In the cases we have been able to compute so far, the tautological cohomology with twisted coefficients is always much simpler to understand, even though it “contains the same information”. In particular we hope to be able to find a systematic way of analyzing the consequences of the recent conjecture that Pixton’s relations are all relations between tautological classes; until now, most concrete consequences of Pixton’s conjecture have been found via extensive computer calculations, which are feasible only when the genus and number of markings is small.
The second project has a somewhat different flavor, involving operads and periods of moduli spaces, and builds upon recent work of myself with Johan Alm, who I will continue to collaborate with. This work is strongly informed by Brown’s breakthrough results relating mixed motives over Spec(Z) and multiple zeta values to the periods of moduli spaces of genus zero Riemann surfaces. In brief, Brown introduced a partial compactification of the moduli space M_{0,n} of n-pointed genus zero Riemann surfaces; we have shown that the spaces M_{0,n} and these partial compactifications are connected by a form of dihedral Koszul duality. It seems likely that this Koszul duality should have further ramifications in the study of multiple zeta values and periods of these spaces; optimistically, this could lead to new irrationality results for multiple zeta values.
Summary
The proposal describes two main projects. Both of them concern cohomology of moduli spaces of Riemann surfaces, but the aims are rather different.
The first is a natural continuation of my work on tautological rings, which I intend to work on with Qizheng Yin and Mehdi Tavakol. In this project, we will introduce a new perspective on tautological rings, which is that the tautological cohomology of moduli spaces of pointed Riemann surfaces can be described in terms of tautological cohomology of the moduli space M_g, but with twisted coefficients. In the cases we have been able to compute so far, the tautological cohomology with twisted coefficients is always much simpler to understand, even though it “contains the same information”. In particular we hope to be able to find a systematic way of analyzing the consequences of the recent conjecture that Pixton’s relations are all relations between tautological classes; until now, most concrete consequences of Pixton’s conjecture have been found via extensive computer calculations, which are feasible only when the genus and number of markings is small.
The second project has a somewhat different flavor, involving operads and periods of moduli spaces, and builds upon recent work of myself with Johan Alm, who I will continue to collaborate with. This work is strongly informed by Brown’s breakthrough results relating mixed motives over Spec(Z) and multiple zeta values to the periods of moduli spaces of genus zero Riemann surfaces. In brief, Brown introduced a partial compactification of the moduli space M_{0,n} of n-pointed genus zero Riemann surfaces; we have shown that the spaces M_{0,n} and these partial compactifications are connected by a form of dihedral Koszul duality. It seems likely that this Koszul duality should have further ramifications in the study of multiple zeta values and periods of these spaces; optimistically, this could lead to new irrationality results for multiple zeta values.
Max ERC Funding
1 091 249 €
Duration
Start date: 2018-01-01, End date: 2022-12-31
Project acronym MorePheno
Project Collider Phenomenology and Event Generators
Researcher (PI) Håkan Torbjörn Sjöstrand
Host Institution (HI) LUNDS UNIVERSITET
Call Details Advanced Grant (AdG), PE2, ERC-2014-ADG
Summary Collider physics is about exploring the smallest constituents of matter, and unravelling the basic laws of the Universe. Unfortunately there can be a huge gap between a one-line formula of a fundamental theory and the experimental reality it implies. Phenomenology is intended to fill that gap, e.g. to explore the consequences of a theory such that it can be directly compared with data.
Nowhere is the gap more striking than for QCD, the theory of strong interactions, which dominates in most high-energy collisions, like at the LHC (Large Hadron Collider) at CERN. And yet, when such collisions produce hundreds of outgoing particles, calculational complexity is insurmountable. Instead ingenious but approximate QCD-inspired models have to be invented.
Such models are especially powerful if they can be cast in the form of computer code, and combined to provide a complete description of the collision process. An event generator is such a code, where random numbers are used to emulate the quantum mechanical uncertainty that leads to no two collision events being quite identical.
The Principal Investigator is the main author of PYTHIA, the most widely used event generator of the last 30 years and vital for physics studies at the LHC. It is in a state of continuous extension: new concepts are invented, new models developed, new code written, to provide an increasingly accurate understanding of collider physics. But precise LHC data has put a demand on far more precise descriptions, and have also shown that some models need to be rethought from the ground up.
This project, at its core, is about conducting more frontline research with direct implications for event generators, embedded in a broader phenomenology context. In addition to the PI, the members of the theoretical high energy physics group in Lund and of the PYTHIA collaboration will participate in this project, as well as graduate students and postdocs.
Summary
Collider physics is about exploring the smallest constituents of matter, and unravelling the basic laws of the Universe. Unfortunately there can be a huge gap between a one-line formula of a fundamental theory and the experimental reality it implies. Phenomenology is intended to fill that gap, e.g. to explore the consequences of a theory such that it can be directly compared with data.
Nowhere is the gap more striking than for QCD, the theory of strong interactions, which dominates in most high-energy collisions, like at the LHC (Large Hadron Collider) at CERN. And yet, when such collisions produce hundreds of outgoing particles, calculational complexity is insurmountable. Instead ingenious but approximate QCD-inspired models have to be invented.
Such models are especially powerful if they can be cast in the form of computer code, and combined to provide a complete description of the collision process. An event generator is such a code, where random numbers are used to emulate the quantum mechanical uncertainty that leads to no two collision events being quite identical.
The Principal Investigator is the main author of PYTHIA, the most widely used event generator of the last 30 years and vital for physics studies at the LHC. It is in a state of continuous extension: new concepts are invented, new models developed, new code written, to provide an increasingly accurate understanding of collider physics. But precise LHC data has put a demand on far more precise descriptions, and have also shown that some models need to be rethought from the ground up.
This project, at its core, is about conducting more frontline research with direct implications for event generators, embedded in a broader phenomenology context. In addition to the PI, the members of the theoretical high energy physics group in Lund and of the PYTHIA collaboration will participate in this project, as well as graduate students and postdocs.
Max ERC Funding
1 990 895 €
Duration
Start date: 2015-11-01, End date: 2020-10-31
