Searcharxiv⌕ Search

arXiv subjects

Thang Le

Publications and source records attributed to Thang Le.

12 recordsLinked to original sources
arXiv2023

Skein Algebras of Three-Manifolds at 4th Roots of Unity

This paper introduces an algebra structure on the part of the skein module of an arbitrary $3$-manifold $M$ spanned by links that represent $0$ in $H_1(M;\mathbb{Z}_2)$ when the value of the parameter used in the Kauffman bracket skein relation is equal to $\pm {\bf i}$. It is proved that if $M$ has no $2$-torsion in $H_1(M;\mathbb{Z})$ then those algebras, $K_{\pm {\bf i}}^0(M)$, are naturally isomorphic to the corresponding algebras when the value of the parameter is $\pm 1$. This implies that the algebra $K_{\pm{\bf i}}^0(M)$ is the unreduced coordinate ring of the variety of $PSL_2(\mathbb{C})$-characters of $π_1(M)$ that lift to $SL_2(\mathbb{C})$-representations.

math.GT↗
arXiv2019

Dimension and Trace of the Kauffman Bracket Skein Algebra

Let $F$ be a finite type surface and $ζ$ a complex root of unity. The Kauffman bracket skein algebra $K_ζ(F)$ is an important object in both classical and quantum topology as it has relations to the character variety, the Teichmüller space, the Jones polynomial, and the Witten-Reshetikhin-Turaev Topological Quantum Field Theories. We compute the rank and trace of $K_ζ(F)$ over its center, and we extend a theorem of Frohman and Kania-Bartoszynska which says the skein algebra has a splitting coming from two pants decompositions of $F$.

math.GT↗
arXiv2012

Homology torsion growth and Mahler measure

We prove a conjecture of K. Schmidt in algebraic dynamical system theory on the growth of the number of components of fixed point sets. We also generalize a result of Silver and Williams on the growth of homology torsions of finite abelian covering of link complements. In both cases, the growth is expressed by the Mahler measure of the first non-zero Alexander polynomial of the corresponding modules. We use the notion of pseudo-isomorphism, and also tools from commutative algebra and algebraic geometry, to reduce the conjectures to the case of torsion modules. We also describe concrete sequences which give the expected values of the limits in both cases. For this part we utilize a result of Bombieri and Zannier (conjectured before by A. Schinzel) and a result of Lawton (conjectured before by D. Boyd).

math.GT↗
arXiv2011

On the unification of quantum 3-manifold invariants

In 2006 Habiro initiated a construction of generating functions for Witten-Reshetikhin-Turaev (WRT) invariants known as unified WRT invariants. In a series of papers together with Irmgard Buehler and Christian Blanchet we extended his construction to a larger class of 3-manifolds. The unified invariants provide a strong tool to study properties of the whole collection of WRT invariants, e.g. their integrality, and hence, their categorification. In this paper we give a survey on ideas and techniques used in the construction of the unified invariants.

math.GT↗
arXiv2009

A Unified Quantum SO(3) Invariant for Rational Homology 3-Spheres

Given a rational homology 3-sphere M with the first integral homology of rank b and a link L inside M, colored by odd numbers, we construct a unified invariant I_{M,L} belonging to a modification of the Habiro ring where b is inverted. Our unified invariant dominates the whole set of the SO(3) Witten-Reshetikhin-Turaev invariants of the pair (M,L). If b=1 and L is empty, I_M coincides with Habiro's invariant of integral homology 3-spheres. For b>1, the unified invariant defined by the third author is determined by I_M. One of the applications are the new Ohtsuki series (perturbative expansions of I_M at roots of unity) dominating all quantum SO(3) invariants.

math.GT↗
arXiv2005

Almost integral TQFTs from simple Lie algebras

Almost integral TQFTs were introduced by Gilmer [Duke Math. J. 125 (2004) 389--413]. The aim of this paper is to modify the TQFT of the category of extended 3-cobordisms given by Turaev (in his book: Quantum invariants of knots and 3-manifolds) to obtain an almost integral TQFT.

math.QA↗
arXiv2005

Laplace transform and universal sl(2) invariants

We develop a Laplace transform method for constructing universal invariants of 3-manifolds. As an application, we recover Habiro's theory of integer homology 3-spheres and extend it to some classes of rational homology 3-spheres with cyclic homology. If |H_1|=2, we give explicit formulas for universal invariants dominating the sl(2) and SO(3) Witten--Reshetikhin--Turaev invariants, as well as their spin and cohomological refinements at all roots of unity. New results on the Ohtsuki series and the integrality of quantum invariants are the main applications of our construction.

math.QA↗
arXiv2002

Representations of Double Affine Lie algebras

We study representations of the double affine Lie algebra associated to a simple Lie algebra. We construct a family of indecomposable integrable representations and identify their irreducible quotients. We also give a condition for the indecomposable modules to be irreducible, this is analogous to a result in the representation theory of quantum affine algebras. Finally, in the last section of the paper, we show, by using the notion of fusion product, that our modules are generically reducible.

math.QA↗
arXiv2001

Quantum groups and ribbon G-categories

For a group G, the notion of a ribbon G-category was introduced by the second author in a previous work with a view towards constructing 3-dimensional homotopy quantum field theories (HQFT's) with target K(G,1). We discuss here how to derive ribbon G-categories from a simple complex Lie algebra g where G is the center of g. The construction is based on a study of representations of the quantum group $U_q(g)$ at a root of unity. Under certain assumptions on the root of unity, the resulting G-categories give rise to numerical invariants of pairs (a closed oriented 3-manifold M, an element of $H^1(M;G)$) and to 3-dimensional HQFT's.

math.QA↗