Project acronym CHANGE
Project CHallenges in ANalysis and GEometry, between mean and scalar curvature
Researcher (PI) Alessandro Carlotto
Host Institution (HI) EIDGENOESSISCHE TECHNISCHE HOCHSCHULE ZUERICH
Country Switzerland
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary The interplay between Analysis and Geometry has led to a number of spectacular achievements such as the proof of the Poincaré conjecture by Perelman. The goal of this proposal is to establish a research group that will make striking progress along the following two directions, that reflect the two souls, extrinsic and intrinsic, of Riemannian Geometry, as well as their mutual interaction.
Minimal surfaces, namely surfaces of zero mean curvature, have been an object of mathematical study since the 18th century (with pioneering work by Lagrange and Euler), and yet remain at the heart of many problems to this day. I aim at shading new light on their understanding, by means of a thorough investigation of the Morse index as an observable on the space of minimal cycles, both in general 3-manifolds of positive curvature and in space forms, towards higher Urbano-type theorems and beyond min-max techniques.
Partly motivated by the study of data sets for the Einstein equations on the one hand, and by a far-reaching program by Gromov on the other, we also want to systematically study the interplay between the scalar curvature of a manifold and the mean curvature of its boundary. The project, which builds on my recent contributions and long-term experience in the field, relies on a combination of diverse elliptic and parabolic techniques, and aims at developing effective deformation methods that will have a variety of applications.
These directions, while seemingly different, are deeply intertwined both at the technical and conceptual level, and incarnate the primary goal of redefining the state of the art in the investigation of infinite-dimensional spaces of solutions to fundamental geometric problems.
Summary
The interplay between Analysis and Geometry has led to a number of spectacular achievements such as the proof of the Poincaré conjecture by Perelman. The goal of this proposal is to establish a research group that will make striking progress along the following two directions, that reflect the two souls, extrinsic and intrinsic, of Riemannian Geometry, as well as their mutual interaction.
Minimal surfaces, namely surfaces of zero mean curvature, have been an object of mathematical study since the 18th century (with pioneering work by Lagrange and Euler), and yet remain at the heart of many problems to this day. I aim at shading new light on their understanding, by means of a thorough investigation of the Morse index as an observable on the space of minimal cycles, both in general 3-manifolds of positive curvature and in space forms, towards higher Urbano-type theorems and beyond min-max techniques.
Partly motivated by the study of data sets for the Einstein equations on the one hand, and by a far-reaching program by Gromov on the other, we also want to systematically study the interplay between the scalar curvature of a manifold and the mean curvature of its boundary. The project, which builds on my recent contributions and long-term experience in the field, relies on a combination of diverse elliptic and parabolic techniques, and aims at developing effective deformation methods that will have a variety of applications.
These directions, while seemingly different, are deeply intertwined both at the technical and conceptual level, and incarnate the primary goal of redefining the state of the art in the investigation of infinite-dimensional spaces of solutions to fundamental geometric problems.
Max ERC Funding
1 342 500 €
Duration
Start date: 2021-03-01, End date: 2026-02-28
Project acronym ChromSpaces
Project Chromatic homotopy theory of spaces
Researcher (PI) Gijs (Gijsbert Scheltus Karel Sebastiaan) Heuts
Host Institution (HI) UNIVERSITEIT UTRECHT
Country Netherlands
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary Many current developments in stable homotopy theory are guided by the ‘chromatic perspective’. One decomposes a spectrum into its monochromatic pieces, each of which is a localization corresponding to one of the prime fields of higher algebra (the Morava K-theories, generalizing the prime fields Q and F_p of ordinary algebra). The goal of this proposal is to study the chromatic decomposition of spaces, as opposed to that of spectra. I will establish structural results for the category of all monochromatic spaces ‘of a given color’ and study the assembly question: how to put the pieces back together to retrieve information about the original space? The techniques are informed by my recent results relating monochromatic spaces to spectral Lie algebras, which generalize Quillen’s rational homotopy theory to all the other relevant chromatic localizations of homotopy theory. More precisely, this research has the following goals. 1. Develop the structure theory of spectral Lie algebras and apply it to monochromatic spaces. This includes understanding Koszul duality between spectral Lie algebras and commutative ring spectra, with applications to a conjecture of Francis-Gaitsgory, and decomposition results for spectral Lie algebras, with applications to torsion exponents of homotopy groups, building on classical work of Cohen-Moore-Neisendorfer. 2. Develop a theory of transchromatic spectral Lie algebras, explaining how the different monochromatic pieces of homotopy theory interact. This connects to my previous work on the Goodwillie tower of homotopy theory and Tate coalgebras.
Summary
Many current developments in stable homotopy theory are guided by the ‘chromatic perspective’. One decomposes a spectrum into its monochromatic pieces, each of which is a localization corresponding to one of the prime fields of higher algebra (the Morava K-theories, generalizing the prime fields Q and F_p of ordinary algebra). The goal of this proposal is to study the chromatic decomposition of spaces, as opposed to that of spectra. I will establish structural results for the category of all monochromatic spaces ‘of a given color’ and study the assembly question: how to put the pieces back together to retrieve information about the original space? The techniques are informed by my recent results relating monochromatic spaces to spectral Lie algebras, which generalize Quillen’s rational homotopy theory to all the other relevant chromatic localizations of homotopy theory. More precisely, this research has the following goals. 1. Develop the structure theory of spectral Lie algebras and apply it to monochromatic spaces. This includes understanding Koszul duality between spectral Lie algebras and commutative ring spectra, with applications to a conjecture of Francis-Gaitsgory, and decomposition results for spectral Lie algebras, with applications to torsion exponents of homotopy groups, building on classical work of Cohen-Moore-Neisendorfer. 2. Develop a theory of transchromatic spectral Lie algebras, explaining how the different monochromatic pieces of homotopy theory interact. This connects to my previous work on the Goodwillie tower of homotopy theory and Tate coalgebras.
Max ERC Funding
1 500 000 €
Duration
Start date: 2021-01-01, End date: 2025-12-31
Project acronym DAFNE
Project Discretization and adaptive approximation of fully nonlinear equations
Researcher (PI) Dietmar Gallistl
Host Institution (HI) FRIEDRICH-SCHILLER-UNIVERSITAT JENA
Country Germany
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary Fully nonlinear partial differential equations (PDE) arise in many applications ranging from physics to economy. They are different from PDEs in mechanics, and the PDE theory relies on the generalized solution concept of so-called viscosity solutions. Monotone finite difference methods (FDM) are provably convergent for approximating viscosity solutions, but are restricted to regular meshes and low-order approximations, thus having limitations in resolving realistic geometries or dealing with local mesh refinement. As viscosity solutions are lacking smoothness properties in general, adaptive approximations are desirable. In contrast to FDM, finite element methods (FEM) offer the possibility of high-order approximations with flexibility in adaptive and automatic mesh design. However, provably convergent FEM formulations for viscosity solutions to nonvariational problems are as yet unknown.
With a background in the numerical analysis of PDEs, especially the theory of FEM and adaptive algorithms, DAFNE aims at laying the theoretical and practical foundation for the application of FEM and automatic mesh-refinement algorithms to fully nonlinear equations. The focus is on the large class of Hamilton-Jacobi-Bellman (HJB) equations. They originated from stochastic control problems, but more generally comprise many classical and relevant equations like Pucci's equation or the Monge-Ampère equation
with applications in finance, optimal transport, physics, and geometry.
The novel approach is to estimate local regularity properties through the control variable in the HJB formulation. This (a) gives rise to new regularization strategies and (b) indicates where the mesh needs to be refined. Both achievements are key to the design of a new FEM formulation.
The project is at the frontiers of PDE analysis, numerical analysis, and scientific computing. The long-term goal is to establish the first convergence proofs for adaptive FEM simulations of fully nonlinear phenomena.
Summary
Fully nonlinear partial differential equations (PDE) arise in many applications ranging from physics to economy. They are different from PDEs in mechanics, and the PDE theory relies on the generalized solution concept of so-called viscosity solutions. Monotone finite difference methods (FDM) are provably convergent for approximating viscosity solutions, but are restricted to regular meshes and low-order approximations, thus having limitations in resolving realistic geometries or dealing with local mesh refinement. As viscosity solutions are lacking smoothness properties in general, adaptive approximations are desirable. In contrast to FDM, finite element methods (FEM) offer the possibility of high-order approximations with flexibility in adaptive and automatic mesh design. However, provably convergent FEM formulations for viscosity solutions to nonvariational problems are as yet unknown.
With a background in the numerical analysis of PDEs, especially the theory of FEM and adaptive algorithms, DAFNE aims at laying the theoretical and practical foundation for the application of FEM and automatic mesh-refinement algorithms to fully nonlinear equations. The focus is on the large class of Hamilton-Jacobi-Bellman (HJB) equations. They originated from stochastic control problems, but more generally comprise many classical and relevant equations like Pucci's equation or the Monge-Ampère equation
with applications in finance, optimal transport, physics, and geometry.
The novel approach is to estimate local regularity properties through the control variable in the HJB formulation. This (a) gives rise to new regularization strategies and (b) indicates where the mesh needs to be refined. Both achievements are key to the design of a new FEM formulation.
The project is at the frontiers of PDE analysis, numerical analysis, and scientific computing. The long-term goal is to establish the first convergence proofs for adaptive FEM simulations of fully nonlinear phenomena.
Max ERC Funding
1 453 937 €
Duration
Start date: 2021-07-01, End date: 2026-06-30
Project acronym FluFloRan
Project Mathematical analysis of fluid flows: the challenge of randomness
Researcher (PI) Martina Hofmanova
Host Institution (HI) UNIVERSITAET BIELEFELD
Country Germany
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary The main goal of the present project is to make substantial contributions to the understanding of fundamental problems in the mathematical theory of fluid flows. This theory is formulated in terms of systems of nonlinear partial differential equations (PDEs). Major attention has been paid to the iconic example, the Navier-Stokes system for incompressible fluids, and the corresponding Millennium Problem. Despite joint efforts and a substantial progress for various models in fluid dynamics, fundamental questions concerning existence and uniqueness of solutions as well as long time behavior remain unsolved.
This project is based on the conviction that a probabilistic description is indispensable in modeling of fluid flows to capture the chaotic behavior of deterministic systems after blow-up, and to describe model uncertainties due to high sensitivity to input data or parameter reduction. For a set of selected models, we investigate different aspects of the underlying deterministic and stochastic PDE dynamics. In particular, we are concerned with the question of solvability and well-posedness or alternatively ill-posedness. For some models including the incompressible stochastic Navier-Stokes system we investigate non-uniqueness in law. For the compressible counterpart we aim to prove existence of a unique ergodic invariant measure.
The guiding theme of this research program is a core question in the field, namely, how to select physically relevant solutions to PDEs in fluid dynamics. The project lies at the challenging frontiers of PDE theory and probability theory and it will tackle several long standing open problems. The results will have an impact in the deterministic PDE theory, stochastic partial differential equations and from a wider perspective also in mathematical physics.
Summary
The main goal of the present project is to make substantial contributions to the understanding of fundamental problems in the mathematical theory of fluid flows. This theory is formulated in terms of systems of nonlinear partial differential equations (PDEs). Major attention has been paid to the iconic example, the Navier-Stokes system for incompressible fluids, and the corresponding Millennium Problem. Despite joint efforts and a substantial progress for various models in fluid dynamics, fundamental questions concerning existence and uniqueness of solutions as well as long time behavior remain unsolved.
This project is based on the conviction that a probabilistic description is indispensable in modeling of fluid flows to capture the chaotic behavior of deterministic systems after blow-up, and to describe model uncertainties due to high sensitivity to input data or parameter reduction. For a set of selected models, we investigate different aspects of the underlying deterministic and stochastic PDE dynamics. In particular, we are concerned with the question of solvability and well-posedness or alternatively ill-posedness. For some models including the incompressible stochastic Navier-Stokes system we investigate non-uniqueness in law. For the compressible counterpart we aim to prove existence of a unique ergodic invariant measure.
The guiding theme of this research program is a core question in the field, namely, how to select physically relevant solutions to PDEs in fluid dynamics. The project lies at the challenging frontiers of PDE theory and probability theory and it will tackle several long standing open problems. The results will have an impact in the deterministic PDE theory, stochastic partial differential equations and from a wider perspective also in mathematical physics.
Max ERC Funding
1 500 000 €
Duration
Start date: 2021-03-01, End date: 2026-02-28
Project acronym GeoSub
Project Geometric analysis of sub-Riemannian spaces through interpolation inequalities
Researcher (PI) Luca Rizzi
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary Sub-Riemannian spaces are geometrical structures that model constrained systems, and constitute a vast generalization of Riemannian geometry. They arise in control theory, harmonic and complex analysis, subelliptic PDEs, geometric measure theory, calculus of variations, optimal transport, and potential analysis.
In the last 10 years, a surge of interest in the study of geometric and functional inequalities on sub-Riemannian spaces revealed unexpected behaviours and intriguing phenomena that failed to fit into the classical schemes inspired by Riemannian geometry. In this project, I aim to develop a framework of geometric and functional interpolation inequalities adapted to sub-Riemannian manifolds, and to use this theory to tackle old and new problems concerning the geometric analysis of these structures.
The project focuses on the following interconnected topics: (i) the development of a unifying theory of curvature bounds including sub-Riemannian structures, (ii) the study of measure contraction properties of Carnot groups, (iii) applications to isoperimetric-type problems, and (iv) applications to the regularity of the sub-Riemannian heat kernel at the cut locus. The project adopts a unique approach combining methods from geometric control theory, optimal transport and comparison geometry that I developed in recent years, and which already allowed me and my collaborators to obtain important results in the field.
The project aims to achieve an ambitious unification program, solve long-standing problems, and explore new research directions in sub-Riemannian geometry, with an impact in several neighbouring areas, including geometric analysis on non-smooth spaces, analysis of hypoelliptic operators, geometric measure theory, spectral geometry. My long-term purpose is to build a leading research group in sub-Riemannian geometry, to significantly advance our understanding of Geometry under non-holonomic constraints.
Summary
Sub-Riemannian spaces are geometrical structures that model constrained systems, and constitute a vast generalization of Riemannian geometry. They arise in control theory, harmonic and complex analysis, subelliptic PDEs, geometric measure theory, calculus of variations, optimal transport, and potential analysis.
In the last 10 years, a surge of interest in the study of geometric and functional inequalities on sub-Riemannian spaces revealed unexpected behaviours and intriguing phenomena that failed to fit into the classical schemes inspired by Riemannian geometry. In this project, I aim to develop a framework of geometric and functional interpolation inequalities adapted to sub-Riemannian manifolds, and to use this theory to tackle old and new problems concerning the geometric analysis of these structures.
The project focuses on the following interconnected topics: (i) the development of a unifying theory of curvature bounds including sub-Riemannian structures, (ii) the study of measure contraction properties of Carnot groups, (iii) applications to isoperimetric-type problems, and (iv) applications to the regularity of the sub-Riemannian heat kernel at the cut locus. The project adopts a unique approach combining methods from geometric control theory, optimal transport and comparison geometry that I developed in recent years, and which already allowed me and my collaborators to obtain important results in the field.
The project aims to achieve an ambitious unification program, solve long-standing problems, and explore new research directions in sub-Riemannian geometry, with an impact in several neighbouring areas, including geometric analysis on non-smooth spaces, analysis of hypoelliptic operators, geometric measure theory, spectral geometry. My long-term purpose is to build a leading research group in sub-Riemannian geometry, to significantly advance our understanding of Geometry under non-holonomic constraints.
Max ERC Funding
1 171 465 €
Duration
Start date: 2021-09-01, End date: 2026-08-31
Project acronym ISOPERIMETRY
Project Sharp Isoperimetric Inequalities - Old and New
Researcher (PI) Emanuel MILMAN
Host Institution (HI) TECHNION - ISRAEL INSTITUTE OF TECHNOLOGY
Country Israel
Call Details Consolidator Grant (CoG), PE1, ERC-2020-COG
Summary Isoperimetric inequalities constitute some of the most beautiful and ancient results in geometry, and play a key role in numerous facets of differential geometry, analysis, calculus of variations, geometric measure theory, minimal surfaces, probability and more.
Isoperimetric minimizers have classically been determined on Euclidean, spherical, hyperbolic and Gaussian spaces. The isoperimetric problem is well-understood on surfaces, but besides some minor variations on these examples and some three-dimensional cases, remains open on numerous fundamental spaces, like projective spaces, the flat torus or hypercube, and for symmetric sets in Gaussian space. When partitioning the space into multiple regions of prescribed volume so that the common surface-area is minimized, the Euclidean double-bubble conjecture was established by Hutchings-Morgan-Ritoré-Ros, and the Gaussian multi-bubble conjecture was recently established in our work with Neeman, but the Euclidean and spherical multi-bubble conjectures remain wide open. Isoperimetric comparison theorems like the Gromov-Lévy and Bakry-Ledoux theorems are well-understood under a Ricci curvature lower bound, but under an upper-bound K ≤ 0 on the sectional curvature, the Cartan-Hadamard conjecture remains open in dimension five and higher despite recent progress. In the sub-Riemannian setting, the isoperimetric problem remains open on the simplest example of the Heisenberg group.
The above long-standing problems lie at the very forefront of the theory and present some of the biggest challenges on both conceptual and technical levels. Any progress made would be extremely important and would open the door for tackling even more general isoperimetric problems. To address these questions, we propose adding several concrete new tools, some of which have only recently become available, to the traditional ones typically used in the study of isoperimetric problems.
Summary
Isoperimetric inequalities constitute some of the most beautiful and ancient results in geometry, and play a key role in numerous facets of differential geometry, analysis, calculus of variations, geometric measure theory, minimal surfaces, probability and more.
Isoperimetric minimizers have classically been determined on Euclidean, spherical, hyperbolic and Gaussian spaces. The isoperimetric problem is well-understood on surfaces, but besides some minor variations on these examples and some three-dimensional cases, remains open on numerous fundamental spaces, like projective spaces, the flat torus or hypercube, and for symmetric sets in Gaussian space. When partitioning the space into multiple regions of prescribed volume so that the common surface-area is minimized, the Euclidean double-bubble conjecture was established by Hutchings-Morgan-Ritoré-Ros, and the Gaussian multi-bubble conjecture was recently established in our work with Neeman, but the Euclidean and spherical multi-bubble conjectures remain wide open. Isoperimetric comparison theorems like the Gromov-Lévy and Bakry-Ledoux theorems are well-understood under a Ricci curvature lower bound, but under an upper-bound K ≤ 0 on the sectional curvature, the Cartan-Hadamard conjecture remains open in dimension five and higher despite recent progress. In the sub-Riemannian setting, the isoperimetric problem remains open on the simplest example of the Heisenberg group.
The above long-standing problems lie at the very forefront of the theory and present some of the biggest challenges on both conceptual and technical levels. Any progress made would be extremely important and would open the door for tackling even more general isoperimetric problems. To address these questions, we propose adding several concrete new tools, some of which have only recently become available, to the traditional ones typically used in the study of isoperimetric problems.
Max ERC Funding
1 745 000 €
Duration
Start date: 2022-10-01, End date: 2027-09-30
Project acronym MMiMMa
Project MMP and Mirrors via Maximal Modification Algebras
Researcher (PI) Michael WEMYSS
Host Institution (HI) UNIVERSITY OF GLASGOW
Country United Kingdom
Call Details Consolidator Grant (CoG), PE1, ERC-2020-COG
Summary Geometrically, this proposal is concerned primarily with Calabi--Yau threefolds, their (local) classification, their homological properties, various associated structures such as stability conditions and Frobenius manifolds, and the resulting predictions across mirror symmetry. Our approach to these problems is through noncommutative algebra, and necessarily so. We will use techniques from contraction algebras and noncommutative resolutions to classify, using both theoretical and constructive methods, and in the process verify an amended version of a string theory prediction. We will use this to push forward curve-counting and derived category consequences and obstructions, and will work towards building a full database of 3-fold flops. On a parallel track, we will treat fundamental problems in noncommutative resolutions and their variants, and approach some of the founding conjectures in the area. We will tackle problems such as existence of MMAs through to more specific problems such as faithful actions and K(pi,1) through stability manifolds and tilting theory on preprojective algebras. We will furthermore merge all this into an emerging theory of Frobenius manifolds, SKMS, and schobers, and through this expand on recent work constructing mirrors to various flopping contractions.
Summary
Geometrically, this proposal is concerned primarily with Calabi--Yau threefolds, their (local) classification, their homological properties, various associated structures such as stability conditions and Frobenius manifolds, and the resulting predictions across mirror symmetry. Our approach to these problems is through noncommutative algebra, and necessarily so. We will use techniques from contraction algebras and noncommutative resolutions to classify, using both theoretical and constructive methods, and in the process verify an amended version of a string theory prediction. We will use this to push forward curve-counting and derived category consequences and obstructions, and will work towards building a full database of 3-fold flops. On a parallel track, we will treat fundamental problems in noncommutative resolutions and their variants, and approach some of the founding conjectures in the area. We will tackle problems such as existence of MMAs through to more specific problems such as faithful actions and K(pi,1) through stability manifolds and tilting theory on preprojective algebras. We will furthermore merge all this into an emerging theory of Frobenius manifolds, SKMS, and schobers, and through this expand on recent work constructing mirrors to various flopping contractions.
Max ERC Funding
1 889 131 €
Duration
Start date: 2021-06-01, End date: 2026-05-31
Project acronym MRKT
Project Foundations of Motivic Real K-Theory
Researcher (PI) Yonatan Harpaz
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary Quadratic forms are ubiquitous throughout mathematics, playing a fundamental role in areas from arithmetic through algebra and geometry. In surgery theory, quadratic forms feature prominently in the classification of smooth manifolds in a given homotopy type, while in arithmetic geometry they can be used to encode Galois and motivic cohomology classes via Milnor's conjecture. The theory of quadratic forms is naturally very sensitive to the prime 2. While in surgery theory this effect is critical, in algebraic geometry it was often set aside by assuming 2 to be invertible in all ground rings. A recent joint work of the PI and collaborators on the foundations of Hermitian K-theory uses state-of-the-art tools from higher category theory to develop a new framework for the subject, bringing a bordism theoretical approach to the algebraic study of quadratic forms, all while accommodating for the subtleties posed by the prime 2.
Building on this recent success, the project MRKT aims to remove the theoretical barrier of the prime 2 from the study of Hermitian K-theory in the domain of algebraic geometry, and set up the foundations of motivic Hermitian K-theory and real algebraic K-theory over the integers.
Summary
Quadratic forms are ubiquitous throughout mathematics, playing a fundamental role in areas from arithmetic through algebra and geometry. In surgery theory, quadratic forms feature prominently in the classification of smooth manifolds in a given homotopy type, while in arithmetic geometry they can be used to encode Galois and motivic cohomology classes via Milnor's conjecture. The theory of quadratic forms is naturally very sensitive to the prime 2. While in surgery theory this effect is critical, in algebraic geometry it was often set aside by assuming 2 to be invertible in all ground rings. A recent joint work of the PI and collaborators on the foundations of Hermitian K-theory uses state-of-the-art tools from higher category theory to develop a new framework for the subject, bringing a bordism theoretical approach to the algebraic study of quadratic forms, all while accommodating for the subtleties posed by the prime 2.
Building on this recent success, the project MRKT aims to remove the theoretical barrier of the prime 2 from the study of Hermitian K-theory in the domain of algebraic geometry, and set up the foundations of motivic Hermitian K-theory and real algebraic K-theory over the integers.
Max ERC Funding
1 331 091 €
Duration
Start date: 2021-01-01, End date: 2025-12-31
Project acronym NAMirror
Project Non-archimedean Mirror Symmetry
Researcher (PI) Tony Yue YU
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary Mirror symmetry is one of the most mysterious dualities in mathematics. Roughly, it predicts that given any Calabi-Yau variety, there exists a mirror Calabi-Yau variety such that a rich list of geometric relations hold between the two, involving Hodge numbers, Gromov-Witten invariants, variation of Hodge structures, Floer homology (Fukaya category), coherent sheaves, stability conditions and so on. Despite continual progress in the subject, a fundamental question remains unclear: to what extent do mirrors exist, and how to construct the mirror variety?
Here we propose a new approach to answer this question, based on latest developments from non-archimedean geometry, in particular the theory of Berkovich spaces, as well as derived non-archimedean geometry. Our goal is to conceive and pursue a full-fledged theory of non-archimedean mirror symmetry, which will lead to new results unattainable from existing methods.
We propose to work out a general mirror construction, starting directly from a non-archimedean Strominger-Yau-Zaslow torus fibration, conjectured by Kontsevich-Soibelman, by counting non-archimedean analytic disks with boundaries on SYZ torus fibers. First we need to establish the existence of such counts in full generality, based on non-archimedean Gromov-Witten theory and tail conditions. Then we have to prove various properties of the mirror algebra, including associativity, radius of convergence and singularity estimates. Finally we propose to use wall-crossing formulas to glue local mirror algebras together to obtain the global mirror variety. A long-term goal is to show that the mirror construction is an involution, the best exhibition of mirror duality.
We also aim for applications outside mirror symmetry, in particular towards the moduli of KSBA stable pairs in birational geometry. Our project is intimately related to the ongoing Gross-Siebert program based on logarithmic geometry. We also expect fruitful future interactions with their program.
Summary
Mirror symmetry is one of the most mysterious dualities in mathematics. Roughly, it predicts that given any Calabi-Yau variety, there exists a mirror Calabi-Yau variety such that a rich list of geometric relations hold between the two, involving Hodge numbers, Gromov-Witten invariants, variation of Hodge structures, Floer homology (Fukaya category), coherent sheaves, stability conditions and so on. Despite continual progress in the subject, a fundamental question remains unclear: to what extent do mirrors exist, and how to construct the mirror variety?
Here we propose a new approach to answer this question, based on latest developments from non-archimedean geometry, in particular the theory of Berkovich spaces, as well as derived non-archimedean geometry. Our goal is to conceive and pursue a full-fledged theory of non-archimedean mirror symmetry, which will lead to new results unattainable from existing methods.
We propose to work out a general mirror construction, starting directly from a non-archimedean Strominger-Yau-Zaslow torus fibration, conjectured by Kontsevich-Soibelman, by counting non-archimedean analytic disks with boundaries on SYZ torus fibers. First we need to establish the existence of such counts in full generality, based on non-archimedean Gromov-Witten theory and tail conditions. Then we have to prove various properties of the mirror algebra, including associativity, radius of convergence and singularity estimates. Finally we propose to use wall-crossing formulas to glue local mirror algebras together to obtain the global mirror variety. A long-term goal is to show that the mirror construction is an involution, the best exhibition of mirror duality.
We also aim for applications outside mirror symmetry, in particular towards the moduli of KSBA stable pairs in birational geometry. Our project is intimately related to the ongoing Gross-Siebert program based on logarithmic geometry. We also expect fruitful future interactions with their program.
Max ERC Funding
1 481 550 €
Duration
Start date: 2021-09-01, End date: 2026-08-31
Project acronym NCST
Project Non-compact Chern-Simons Theory, Positive Representations, and Cluster Varieties
Researcher (PI) Alexander Shapiro
Host Institution (HI) THE UNIVERSITY OF EDINBURGH
Country United Kingdom
Call Details Starting Grant (StG), PE1, ERC-2020-STG
Summary Over the past 30 years, deep connections between Chern–Simons theory, supersymmetric (SUSY) gauge theory, and representation theory of quantum groups, have caused an avalanche of research in mathematics and physics. In this proposal I use quantum cluster varieties to develop positive representation theory of quantum groups and a non-compact analogue of Chern–Simons theory. I also obtain new invariants of links and 3-manifolds, and establish new connections between SUSY gauge theories and quantum character varieties. This proposal builds on my prior work, where I prove fundamental cases of the Fock–Goncharov modular functor conjecture in higher Teichmüller theory, and Gaiotto’s conjecture on the existence of cluster structure on K-theoretic Coulomb branches of 3d N = 4 SUSY gauge theories. The proposal is split into the following four projects:
1. Prove the modular functor conjecture and extend it to a non-compact analogue of Chern–Simons theory. Obtain new powerful invariants of links and 3-manifolds.
2. Develop positive representation theory: construct continuous braided monoidal category from positive representations, prove non-compact Peter–Weyl theorem, obtain explicit formulas for finite-dimensional 6j-symbols, prove that the category of positive representations of quantum groups in type A is equivalent to a fusion category in Toda conformal field theory.
3. Describe cluster structure on K-theoretic Coulomb branches of 3d N = 4 SUSY gauge theories, conjectured by Gaiotto. Obtain cluster structure on spherical double affine Hecke algebra, and Slodowy intersections. Provide an algorithm, identifying certain theories of class S with quiver gauge theories.
4. Relate cluster quantization of character varieties with the topological quantum field theory constructed by Ben-Zvi, Brochier, and Jordan. Use it to obtain a canonical quantization of the A-polynomial.
Summary
Over the past 30 years, deep connections between Chern–Simons theory, supersymmetric (SUSY) gauge theory, and representation theory of quantum groups, have caused an avalanche of research in mathematics and physics. In this proposal I use quantum cluster varieties to develop positive representation theory of quantum groups and a non-compact analogue of Chern–Simons theory. I also obtain new invariants of links and 3-manifolds, and establish new connections between SUSY gauge theories and quantum character varieties. This proposal builds on my prior work, where I prove fundamental cases of the Fock–Goncharov modular functor conjecture in higher Teichmüller theory, and Gaiotto’s conjecture on the existence of cluster structure on K-theoretic Coulomb branches of 3d N = 4 SUSY gauge theories. The proposal is split into the following four projects:
1. Prove the modular functor conjecture and extend it to a non-compact analogue of Chern–Simons theory. Obtain new powerful invariants of links and 3-manifolds.
2. Develop positive representation theory: construct continuous braided monoidal category from positive representations, prove non-compact Peter–Weyl theorem, obtain explicit formulas for finite-dimensional 6j-symbols, prove that the category of positive representations of quantum groups in type A is equivalent to a fusion category in Toda conformal field theory.
3. Describe cluster structure on K-theoretic Coulomb branches of 3d N = 4 SUSY gauge theories, conjectured by Gaiotto. Obtain cluster structure on spherical double affine Hecke algebra, and Slodowy intersections. Provide an algorithm, identifying certain theories of class S with quiver gauge theories.
4. Relate cluster quantization of character varieties with the topological quantum field theory constructed by Ben-Zvi, Brochier, and Jordan. Use it to obtain a canonical quantization of the A-polynomial.
Max ERC Funding
1 497 425 €
Duration
Start date: 2021-07-01, End date: 2026-06-30
