Representation theory of solitons
Clay Córdova, Nicholas Holfester, Kantaro Ohmori
Abstract
A bstract Solitons in two-dimensional quantum field theory exhibit patterns of degeneracies and associated selection rules on scattering amplitudes. We develop a representation theory that captures these intriguing features of solitons. This representation theory is based on an algebra we refer to as the strip algebra , $$ {\textbf{Str}}_{\mathcal{C}}\left(\mathcal{M}\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>Str</mml:mi> <mml:mi>C</mml:mi> </mml:msub> <mml:mfenced> <mml:mi>M</mml:mi> </mml:mfenced> </mml:math> , which is defined in terms of the non-invertible symmetry, $$ \mathcal{C} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>C</mml:mi> </mml:math> , a fusion category, and its action on boundary conditions encoded by a module category, $$ \mathcal{M} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>M</mml:mi> </mml:math> . The strip algebra is a C ∗ -weak Hopf algebra, a fact which can be elegantly deduced by quantizing the three-dimensional Drinfeld center TQFT, $$ \mathcal{Z}\left(\mathcal{C}\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Z</mml:mi> <mml:mfenced> <mml:mi>C</mml:mi> </mml:mfenced> </mml:math> , on a spatial manifold with corners. These structures imply that the representation category of the strip algebra is also a unitary fusion category which we identify with a dual category $$ {\mathcal{C}}_{\mathcal{M}}^{\ast } $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>C</mml:mi> <mml:mi>M</mml:mi> <mml:mo>∗</mml:mo> </mml:msubsup> </mml:math> . We present a straightforward method for analyzing these representations in terms of quiver diagrams where nodes are vacua and arrows are solitons and provide examples demonstrating how the representation theory reproduces known degeneracies and selection rules of soliton scattering. Our analysis provides the general framework for analyzing non-invertible symmetry on manifolds with boundary and applies both to the case of boundaries at infinity, relevant to particle physics, and boundaries at finite distance, relevant in conformal field theory or condensed matter systems.