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TQFT, CFT
COMPLETED

Categorical Refraction at Axion–Duality Junctions

Rihaan Shah
Updated 8/8/2026

In four-dimensional theoretical physics, domain walls can alter the fundamental properties of fields crossing them. When an axion domain wall intersects with an electromagnetic duality wall, a mathematical contradiction arises because their respective physical transformations do not commute. The project provides a theoretical framework for resolving this structural mismatch at their two-dimensional intersection. It introduces a phenomenon called categorical refraction, where quantum lines traveling through the junction split into multiple outgoing dyonic sectors. This splitting requires new localized quantum states to resolve the charge mismatch and preserve the underlying symmetry.

The research formalizes the codimension-two intersection formed by an axion domain wall and an electromagnetic duality wall in four-dimensional abelian gauge theory. A central finding identifies the charge-lattice incompatibility using the monodromy operator. The exact measure of failure for the Witten effect and the electromagnetic duality to commute is calculated as:

Mk,g=TkgT−kg−1\mathcal{M}_{k,g} = T_{k}gT_{-k}g^{-1}Mk,g​=Tk​gT−k​g−1

The study proves that a topologically trivial intersection in the uncondensed spin U(1)U(1)U(1) theory exists only when k=0k=0k=0 or c=0c=0c=0. If these conditions fail, the junction must carry nontrivial two-dimensional degrees of freedom, such as a topological sector or conformal defect theory. The generalized transformation law for extended operators crossing the junction, termed categorical refraction, is formulated as:

Rk,g(Lγ)=⨁γ′Vγγ′⊗Lγ′\mathfrak{R}_{k,g}(L_{\gamma}) = \bigoplus_{\gamma'} V_{\gamma}^{\gamma'} \otimes L_{\gamma'}Rk,g​(Lγ​)=γ′⨁​Vγγ′​⊗Lγ′​

The multiplicity space Vγγ′V_{\gamma}^{\gamma'}Vγγ′​ records the required junction states that make each outgoing dyonic sector possible. The work further derives anomaly inflow constraints, constructs candidate compact-boson and finite TQFT junction models, and formulates defect bootstrap equations with categorical recoupling data.

Lead Researchers

R

Rihaan Shah

Research Fellow

Manuscripts & Data

categorical_refraction_paper.pdf
pdf

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