Controlled topological phases and bulk-edge correspondence

In this paper, we introduce a variation of the notion of topological phase reflecting metric structure of the position space. This framework contains not only periodic and non-periodic systems with symmetries in Kitaev's periodic table but also topological crystalline insulators. We also define the bulk and edge indices as invariants taking values in the twisted equivariant $\mathrm{K}$-groups of Roe algebras as generalizations of existing invariants such as the Hall conductance or the Kane--Mele $\mathbb{Z}_2$-invariant. As a consequence, we obtain a new mathematical proof of the bulk-edge correspondence by using the coarse Mayer-Vietoris exact sequence.Comment: 30 pages, Section 2 is completely rewritte

The Joint Spectral Flow and Localization of the Indices of Elliptic Operators

We introduce the notion of the joint spectral flow, which is a generalization of the spectral flow, by using Segal's model of the connective $K$-theory spectrum. We apply it for some localization results of indices motivated by Witten's deformation of Dirac operators and rephrase some analytic techniques in terms of topology.Comment: 35 page

Notes on twisted equivariant K\mathrm{K}-theory for C∗\mathrm{C}^*-algebras

In this paper, we study a generalization of twisted (groupoid) equivariant $\mathrm{K}$-theory in the sense of Freed-Moore for $\mathbb{Z}_2$-graded $\mathrm{C}^*$-algebras. It is defined by using Fredholm operators on Hilbert modules with twisted representations. We compare it with another description using odd symmetries, which is a generalization of van Daele's $\mathrm{K}$-theory for $\mathbb{Z}_2$-graded Banach algebras. In particular, we obtain a simple presentation of the twisted equivariant $\mathrm{K}$-group when the $\mathrm{C}^*$-algebra is trivially graded. It is applied for the bulk-edge correspondence of topological insulators with CT-type symmetries.Comment: 26 pages, minor correction

Compact Lie group actions with continuous Rokhlin property

In this paper, we study continuous Rokhlin property of $\mathrm{C}^*$-dynamical systems using techniques of equivariant $\mathrm{KK}$-theory and quantum group theory. In particular, we determine the $\mathrm{KK}$-equivalence class and give a classification of Kirchberg $G$-algebras when the $G$ is a compact Lie group with Hodgkin condition.Comment: 18 pages. This paper is separated from Section 7 of arXiv:1508.0681

A categorical perspective on the Atiyah-Segal completion theorem in KK\mathrm{KK}-theory

We investigate the homological ideal $\mathfrak{J}_G^H$, the kernel of the restriction functors in compact Lie group equivariant Kasparov categories. Applying the relative homological algebra developed by Meyer and Nest, we relate the Atiyah-Segal completion theorem with the comparison of $\mathfrak{J}_G^H$ with the augmentation ideal of the representation ring. In relation to it, we study on the Atiyah-Segal completion theorem for groupoid equivariant $\mathrm{KK}$-theory, McClure's restriction map theorem, permanence property of the Baum-Connes conjecture under extensions of groups and a class of $\mathfrak{J}_G$-injective objects coming from $\mathrm{C}^*$-dynamical systems, continuous Rokhlin property.Comment: 37 pages. Section 7 is separated to arXiv:1512.06333, minor corrections in Section

The relative Mishchenko--Fomenko higher index and almost flat bundles I: The relative Mishchenko--Fomenko index

In this paper, the first of two, we introduce an alternative definition of the Chang--Weinberger--Yu relative higher index, which is thought of as a relative analogue of the Mishchenko--Fomenko index pairing. A main result of this paper is that our map coincides with the existing relative higher index maps. We make use of this fact for understanding the relative higher index. First, we relate the relative higher index with the higher index of amalgamated free product groups. Second, we define the dual relative higher index map and show its rational surjectivity under certain assumptions.Comment: 30 pages. Section 5, 6, 7, 8 of the previous version are separated to other article

Almost flat relative vector bundles and the almost monodromy correspondence

In this paper we introduce the notion of almost flatness for (stably) relative bundles on a pair of topological spaces and investigate basic properties of it. First, we show that almost flatness of topological and smooth sense are equivalent. This provides a construction of an almost flat stably relative bundle by using the enlargeability of manifolds. Second, we show the almost monodromy correspondence, that is, a correspondence between almost flat (stably) relative bundles and (stably) relative quasi-representations of the fundamental group.Comment: 25 pages, separated from Section 5, 6.2 of arXiv:1807.03181, corrected minor error

Codimension 2 transfer of higher index invariants

This paper is devoted to the study of the higher index theory of codimension $2$ submanifolds originated by Gromov-Lawson and Hanke-Pape-Schick. The first main result is to construct the `codimension $2$ transfer' map from the Higson-Roe analytic surgery exact sequence of a manifold $M$ to that of its codimension $2$ submanifold $N$ under some assumptions on homotopy groups. This map sends the primary and secondary higher index invariants of $M$ to those of $N$. The second is to establish that the codimension 2 transfer map is adjoint to the co-transfer map in cyclic cohomology, defined by the cup product with a group cocycle. This relates the Connes-Moscovici higher index pairing and Lott's higher $\rho$-number of $M$ with those of $N$.Comment: 39 pages; some minor revisions, added Subsection 4.3 and a more detail in Subsection 5.

The index theorem of lattice Wilson--Dirac operators via higher index theory

We give a proof of the index theorem of lattice Wilson--Dirac operators, which states that the index of a twisted Dirac operator on the standard torus is described in terms of the corresponding lattice Wilson--Dirac operator. Our proof is based on the higher index theory of almost flat vector bundles.Comment: 20 page

The bulk-dislocation correspondence for weak topological insulators on screw-dislocated lattices

A weak topological insulator in dimension $3$ is known to have a topologically protected gapless mode along the screw dislocation. In this paper we formulate and prove this fact with the language of C*-algebra K-theory. The proof is based on the coarse index theory of the helical surface.Comment: 17 page