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Differential Models for Anderson Dual to Twisted $\mathrm{Spin}^c$-Bordism and Twisted Anomaly Map

Fei Han, Yuanchu Li

TL;DR

The paper develops differential refinements of twisted $ ext{Spin}^c$-bordism and its Anderson dual, constructing two parallel, equivalent models: a differential extension built from twisted de Rham complexes and currents, and a gerbe-theoretic framework using bundle gerbe modules to encode twists and Dirac-operator data. It then defines a differential twisted anomaly map from $igl( ext{K}^{0}(X, au^{-1})igr)$ to the twisted Anderson dual, realized via the twisted Chern character and reduced eta-invariants in the presence of a differential twist $ au$. The work extends Yamashita–Yonekura’s de Rham models to the twisted setting and proves the equivalence of the differential extensions, including a differential multiplication and pushforward, along with an explicit geometric realization via gerbes. The resulting twisted anomaly map provides a geometric bridge between differential twisted $K$-theory and invertible field theories, aligning with the Stolz–Teichner program and enabling index-theoretic computations for twisted 1|1-dimensional supersymmetric theories.

Abstract

We construct differential models for twisted $\mathrm{Spin}^c$-bordism and for its Anderson dual, and employ the latter to define a twisted anomaly map whose source is the differential twisted $K$-theory. Our differential model for the twisted Anderson dual follows the formalism developed in [YY23]. To connect these constructions with the geometric framework of the Atiyah-Singer index theory, we further present a gerbe-theoretic formulation of our models in terms of bundle gerbes and gerbe modules [Mur96] [BCMMS02]. Within this geometric setting, we define the twisted anomaly map \[ \widehatΦ_{\widehat{\mathcal{G}}}\colon \widehat{K}^{0}(X,\widehat{\mathcal{G}}^{-1}) \longrightarrow \bigl(\widehat{IΩ^{\mathrm{Spin}^c}_{\mathrm{dR}}}\bigr)^{n}(X,\widehat{\mathcal{G}}), \] whose construction naturally involves the reduced eta-invariant of Dirac operators acting on Clifford modules determined by the twisted data. Conceptually, this map is expected to encode the anomalies of twisted $1|1$-dimensional supersymmetric field theories, in accordance with the perspectives developed in [ST11] and [FH21].

Differential Models for Anderson Dual to Twisted $\mathrm{Spin}^c$-Bordism and Twisted Anomaly Map

TL;DR

The paper develops differential refinements of twisted -bordism and its Anderson dual, constructing two parallel, equivalent models: a differential extension built from twisted de Rham complexes and currents, and a gerbe-theoretic framework using bundle gerbe modules to encode twists and Dirac-operator data. It then defines a differential twisted anomaly map from to the twisted Anderson dual, realized via the twisted Chern character and reduced eta-invariants in the presence of a differential twist . The work extends Yamashita–Yonekura’s de Rham models to the twisted setting and proves the equivalence of the differential extensions, including a differential multiplication and pushforward, along with an explicit geometric realization via gerbes. The resulting twisted anomaly map provides a geometric bridge between differential twisted -theory and invertible field theories, aligning with the Stolz–Teichner program and enabling index-theoretic computations for twisted 1|1-dimensional supersymmetric theories.

Abstract

We construct differential models for twisted -bordism and for its Anderson dual, and employ the latter to define a twisted anomaly map whose source is the differential twisted -theory. Our differential model for the twisted Anderson dual follows the formalism developed in [YY23]. To connect these constructions with the geometric framework of the Atiyah-Singer index theory, we further present a gerbe-theoretic formulation of our models in terms of bundle gerbes and gerbe modules [Mur96] [BCMMS02]. Within this geometric setting, we define the twisted anomaly map whose construction naturally involves the reduced eta-invariant of Dirac operators acting on Clifford modules determined by the twisted data. Conceptually, this map is expected to encode the anomalies of twisted -dimensional supersymmetric field theories, in accordance with the perspectives developed in [ST11] and [FH21].

Paper Structure

This paper contains 30 sections, 18 theorems, 285 equations.

Key Result

Proposition 2.1

For the twisted theories represented by the bundle of spectra $P_{\tau}(k)\to X$, there are natural spectral sequences where $L_q(X,P_{\tau}(k))$ is the local system with fiber $\pi_q(k)$ and monodromy induced by the principal $K(\mathbb{Z},2)$-bundle $P\to X$ and the $K(\mathbb{Z},2)$-action on $\pi_q(k)$.

Theorems & Definitions (59)

  • Conjecture 1.1: freed2021reflection
  • Conjecture 1.2: Segal-Stolz-Teichner ST11
  • Definition 1.1: Wang07
  • Definition 1.2: Definition \ref{['def: difftwiSpincStru']}
  • Definition 1.3: Definition \ref{['def: diffSpincBG']}
  • Proposition 2.1
  • Definition 2.2
  • Definition 2.3
  • Definition 3.1: Wang07
  • Definition 3.2
  • ...and 49 more