Quantum theory uses modular group representations to assign invariants to 3-manifolds.
problem Assigning invariants to 3-manifolds via modular group representations.
method Projective representations of the modular group derived from a noncommutative torus.
result Computed traces and determinants of matrices associated with modular group elements.
The paper connects Hodge theory and modular forms to prove inequalities.
problem Proving a conjectural inequality on weights of modular forms.
method Using nonabelian Hodge theory and vector valued modular forms.
result New instances of the three-term inequality for nonunitary representations.
Researchers create projective representations of Hecke groups using TQFT.
problem Constructing projective representations of Hecke groups.
method Using Witten-Reshetikhin-Turaev topological quantum field theory of higher genus surfaces.
result The representation's image group is infinite at low levels in genus 2.
Discoveries new symmetries in 3d topological and physical systems.
problem Identifying hidden symmetries in 3d topological and physical systems.
method Analysis of modular forms, Weil representations, and chiral algebras.
result Identification of new modular structures in 3d theories.
We formulate the unitary rational orbifold conformal field theories in the algebraic quantum field theory framework. Under general conditions, we show that the orbifold of a given unitary rational conformal field theories generates a unitary modular category. Many new unitary modular categories are obtained. We also sh…
Study finds modular classes help in proving Berezin volumes for supersymmetric theories.
problem Existence of Berezin volumes in supergeometric representation theory.
method Cohomological coherence criterion for modular classes of Q-manifolds.
result Established a method to prove the existence of invariant Berezin volumes.
Study fermionic theories, their anomalies, and modular transformations.
problem Understanding fermionic theories and their anomalies.
method Use spin-cobordisms, surgeries, and invertible topological quantum field theories.
result Explicit combinatorial expressions for spin-bordism invariants.
We study the asymptotic behaviour of the quantum representations of the modular group in the large level limit. We prove that each element of the modular group acts as a Fourier integral operator. This provides a link between the classical and quantum Chern-Simons theories for the torus. From this result we deduce the …
TQFT used to study symplectic group modules.
problem Calculating dimensions and characters of specific modules.
method Applied Topological Quantum Field Theory (TQFT).
result Explicit formulae for dimensions and characters.
New techniques prove quantum modularity for various functions.
problem Proving quantum modularity of false theta functions and related series.
method Developed techniques including Poisson summation formula and modular series framework.
result Unified approach to proving quantum modularity for various functions.
We construct families of TQFT's over the finite field Z/pZ starting from an integral TQFT obtained by Frohman and Nicas. These TQFT's are likely to describe the constant order contributions of the cyclotomic integer expansions of the Reshetikhin Turaev Ohtsuki theories. Their modular structure is intimately related to …
The paper develops a new approach to conditional risk measures using modular convex analysis.
problem Developing a new method for conditional risk measures.
method Random modular approach to conditional certainty equivalents and niveloids in the conditional L∞-space. result Retrieves a conditional variational formula for optimized certainty equivalents and applies it to the conditional entropic risk measure.
Researchers clarify modular group representations and vertex operator algebras for 3d invariants.
problem Understanding the full set of 3d invariants and their modular properties.
method Introducing supersymmetric defects and constructing cone vertex operator algebras.
result The full vector-valued quantum modular form for \(\widetilde{
m SL}_2(\mathbb{Z})\) captures all \(\hat Z\)-invariants of a given three-manifold.
We show that once-extended anomalous 3-dimensional topological quantum field theories valued in the 2-category of k-linear categories are in canonical bijection with modular tensor categories equipped with a square root of the global dimension in each factor.
Study projective representations from non-semisimple TQFTs on surfaces.
problem Understanding projective representations of mapping class groups from non-semisimple TQFTs.
method Construct 3D TQFTs using non-semisimple modular categories and analyze projective representations of mapping class groups.
result Projective representations from non-semisimple TQFTs are equivalent to those obtained by Lyubashenko.
We show that the topological modular functor from Witten-Chern-Simons theory is universal for quantum computation in the sense a quantum circuit computation can be efficiently approximated by an intertwining action of a braid on the functor's state space. A computational model based on Chern-Simons theory at a fifth ro…
Classical and quantum Chern-Simons with gauge group U(1)N were classified by Belov and Moore in \cite{belov_moore}. They studied both ordinary topological quantum field theories as well as spin theories. On the other hand a correspondence is well known between ordinary (2+1)-dimensional TQFTs and modular te…
The paper identifies a component of representations mapping modular group elements to isometries with unique fixed points.
problem Characterizing representations of the modular group into isometry groups.
method Analyzing the space of discrete faithful representations of the modular group into Isom(X) for X=SL3(R)/SO(3).
result The space of representations has a component homeomorphic to R^2 x [0,∞), parametrized by Pappus representations and containing Anosov representations.
Semisimplicity proven for conformal blocks representations.
problem Semisimplicity of conformal blocks representations.
method Theory of extensions in non-Abelian Hodge theory and Ocneanu rigidity.
result Semisimplicity of braid group and mapping class group representations.
We construct unitary modular categories for a general class of coset conformal field theories based on our previous study of these theories in the algebraic quantum field theory framework using subfactor theory. We also consider the calculations of the corresponding 3-manifold invariants. It is shown that under certain…
The study examines modular fusion categories with trivial Torelli group actions.
problem Characterizing modular fusion categories with trivial Torelli group actions.
method Analyzing the mapping class group representations and their kernels.
result For modular fusion categories, the Torelli group is contained in the kernel of the genus-g representation if and only if the category is pointed. New 3D TQFTs derived from non-semisimple categories.
problem Constructing topological invariants from non-semisimple categories.
method Using modified traces and Lyubashenko's invariants, with additional assumptions for factorizability.
result Produces new 2+1-TQFTs and monoidal extensions of representations.
Describes representations of modular group into SL(3,R)/SO(3).
problem Understanding representations of modular group into isometry group of symmetric space.
method Analyzes connected component of conjugacy classes of representations.
result Certain representations in the component are Anosov.
Study Eisenstein metrics on modular group representations.
problem Harmonic metrics on automorphic vector bundles.
method Eisenstein series construction for metrics.
result Residue of Eisenstein metrics is a harmonic metric.
New methods detect modular structure in neural networks, revealing surprising effects of dropout.
problem Detecting functional modules in neural networks for learning, compositionality, and generalization.
method Two families of methods: upstream and downstream, to define similarity between units.
result Dropout dramatically increased modularity, and there's little agreement between upstream and downstream methods.
The article is devoted to the qR-conformal modular functors, which being ``deformations'' of the conformal modular functor (the projective representation of the category Train(Diff+(S1)), the train of the group Diff+(S1) of all orientation preserving diffeomorphisms of a circle) in the class of all projectiv…
Geodesic patterns, shears, and Anosov representations of the modular group.
problem Understanding representations of the modular group into Isom(X).
method Analyzing geodesic patterns, shears, and foliations.
result The Barbot component is homeomorphic to R^2 x [0,∞), with interior and boundary properties.
Proves rigidity of SU(2) and SO(3) quantum representations at prime levels.
problem Quantum representations of mapping class groups at prime levels.
method Ocneanu rigidity of modular categories and harmonic representatives in Hodge theory.
result Rigidity of SU(2) and SO(3) quantum representations at all prime levels for closed surfaces of genus at least 7.
Study Alexander polynomials of modular knots, revealing finite and infinite coefficient properties.
problem Investigate Alexander polynomials of modular knots.
method Use Burau representation and geometric SL2(Z)-invariants. result Alexander polynomials of modular knots have both finite and infinite coefficient properties.
Proves representability of complex semigroup systems.
problem Representability of systems of proportionally modular numerical semigroups.
method Canonical equivariant resolution of weighted homogeneous surface singularities.
result Every system of proportionally modular numerical semigroups is representable.
Proves modular operad structure for Riemann surfaces with open and closed boundaries.
problem Understanding modular operads of Riemann surfaces with mixed boundary conditions.
method Proves modular completion, provides finitary presentation, characterizes algebras via morphisms of Frobenius algebras.
result Modular operad structure for Riemann surfaces with mixed boundaries.
In this paper we use fractal geometry to investigate boundary aspects of the first homology group for finite coverings of the modular surface. We obtain a complete description of algebraically invisible parts of this homology group. More precisely, we first show that for any modular subgroup the geodesic forward dynami…
The paper studies algebraic and topological K-theory of Hilbert modular groups.
problem Computing algebraic and topological K-theory for Hilbert modular groups.
method Using Farrell-Jones and Baum-Connes assembly maps, and constructing models for classifying spaces.
result Descriptions of Whitehead groups and topological K-theory for Hilbert modular groups.
Study of modular representations in homology of congruence subgroups.
problem Understanding modular representations in homology of congruence subgroups.
method Analysis of sequences of modular representations of symplectic and special linear groups over finite fields.
result Established periodic representation stability in the sense of Church--Farb.
Our aim is to introduce and advocate non-Σ (non-symmetric) modular operads. While ordinary modular operads were inspired by the structure of the moduli space of stable complex curves, non-Σ modular operads model surfaces with open strings outputs. An immediate application of our theory is a short proof that the mod…
We describe a construction of the modular class associated to a representation up to homotopy of a Lie groupoid. In the case of the adjoint representation up to homotopy, this class is the obstruction to the existence of a volume form, in the sense of Weinstein's "The volume of a differentiable stack".
RNNs solve modular addition tasks using low rank and sparse Fourier structures.
problem Solving modular addition tasks with recurrent neural networks.
method Identified low rank structures and sparse Fourier representations in RNN weights.
result RNNs robust to removing individual frequencies but degrade with more ablation.
Study modular surfaces in Lorentz-Minkowski 3-space, classifying and analyzing their curvature and applications.
problem Understanding the curvature properties of modular surfaces in Lorentz-Minkowski space.
method Analyzing the sign of Gaussian and mean curvature, classifying surfaces, and applying to conformal field theories.
result Complete classification of zero Gaussian curvature modular surfaces and non-existence of non-planar maximal modular surfaces.
ETQFTs created from non-semisimple modular categories.
problem Constructing ETQFTs from non-semisimple modular categories.
method Explicitly identify linear categories and functors in the image of ETQFTs constructed from modular categories.
result The circle category of ETQFTs is equivalent to the full subcategory of projective objects of the underlying modular category, which need not be semisimple.
Connects 4-manifold topology to topological modular forms.
problem Understanding the topology of 4-manifolds.
method Topologically twisted compactification of 6d (1,0) theories on 4-manifolds.
result New invariant of 4-manifolds using equivariant weakly holomorphic modular forms.
E-string theory reveals modular properties of 4-manifold invariants.
problem Understanding the topology of 4-dimensional manifolds.
method Computing partition function on M4imesT2 and verifying its modular properties. result The partition function of the E-string theory is modular and can be lifted to a topological modular form.
Fuchsian groups with a modular embedding have the richest arithmetic properties among non-arithmetic Fuchsian groups. But they are very rare, all known examples being related either to triangle groups or to Teichmueller curves. In Part I of this paper we study the arithmetic properties of the modular embedding and deve…
Introduces modular q-holonomic modules to solve q-difference equations.
problem Solving q-difference equations in quantum invariants and Chern-Simons theory. method Defines modular q-holonomic modules with improved analyticity properties. result Modular q-holonomic modules explain structural properties of quantum invariants and Chern-Simons theory. Classifies elements of cluster modular groups into three types.
problem Classifying elements of cluster modular groups.
method Characterizes elements in terms of fixed points on tropical compactifications.
result Analogous to Nielsen-Thurston classification theory.
Study modular class of Lie ∞-algebroids and their adjoint actions.
problem Understanding the modular class and adjoint actions of Lie ∞-algebroids.
method Equivalence of descriptions, homotopy invariance, explicit actions and dualities.
result Homotopy invariance of modular classes and explicit adjoint actions.
Proposes a topological framework to study modular invariants and related concepts.
problem Exploring modular invariants and related concepts in topological quantum field theory.
method Topological paradigm in alterfold topological quantum field theory.
result Establishes a novel integral identity for modular invariance across multiple Morita contexts.
The paper corrects the use of the transverse density bundle in Lie groupoids.
problem Incorrect use of the transverse density bundle in Lie groupoids.
method Revisiting and clarifying the concepts of transverse density bundle and modular classes.
result The transverse density bundle should be used instead of the common representation QA. In this paper, we introduce the notion of modular class of a Lie algebroid A equipped with a Nambu structure satisfying some suitable hypothesis. We also introduce cohomology and homology theories for such Lie algebroids and prove that these theories are connected by a duality isomorphism when the modular class is nu…