Skip to content
Preprint

Quantum cellular automata and invertible phases of matter

Aug 2026 · 3 citations
Physics Mathematics

Abstract

We introduce and study (fermionic and bosonic) invertible quasi-local algebras over uniformly locally finite metric spaces $X$ with infinite-dimensional local von Neumann algebras. We show that the group of Brauer equivalence classes of such algebras is isomorphic to both the group of phases of invertible states and the group of stable equivalence classes of quantum cellular automata over $X\times \mathbb{Z}$. Using K-theory of the symmetric monoidal category of invertible quasi-local algebras and bounded spread isomorphisms, we propose a definition of an $\Omega$-spectrum of invertible phases as conjectured by Kitaev. We then show that the $c=\frac{1}{2}$ chiral Majorana fermion net and the $(E_{8})_{1}$ conformal net provide Brauer non-trivial invertible quasi-local algebras, thus providing explicit constructions of non-trivial invertible states and quantum cellular automata on $\mathbb{Z}^{2}$. In addition, we show that the time-slice nets of rational diagonal conformal field theories admit lattice degrees of freedom, which implies the discretization of any holomorphic conformal net is invertible.

View source

Similar papers

Preprint Sep 2026

Equivalence of states and bimodule quantum channels

We study the action of quantum channels on states on a von Neumann algebra $\mathcal{M}$ with conserved quantities encoded by a subalgebra $\mathcal{N}$. We define a phase as an equivalence class of normal states on $\mathcal{M}$ under the action of quantum channels preserving $\mathcal{N}$. First, we establish a relat...

Lin-Zhe Huang, Chun-Lan Jiang, Zheng-Wei Liu et al. · 1 citation
Preprint Sep 2026

Vector Bundles of Coinvariants for Admissible Affine Vertex Operator Algebras

Simple affine vertex operator algebras $L_k(\mathfrak{g})$ at non-integral admissible levels $k$ are generally neither $C_2$-cofinite nor rational. Despite the absence of these standard finiteness conditions, we prove that the sheaf of coinvariants (and, dually, of conformal blocks) of ordinary modules in the category...

V. Alekseev, Jian-Qi Liu · 0 citations
Preprint Sep 2026

Discrete $C^*$-Frobenius Algebras and Infinite-Index Extensions in Algebraic Quantum Field Theories

We introduce discrete $C^*$-Frobenius algebras as categorical data for constructing infinite-index extensions of M\"{o}bius covariant nets. The underlying representation is a countable direct sum of simple dualized modules, while the direct sum itself is not necessarily dualizable. Accordingly, rather than requiring a...

Zi-Yun Xu · 0 citations
Preprint Oct 2026

On the Isomorphism of Semicircular Algebras

Building on OpenAI's proof of isomorphism of free group factors, we give a self-contained proof of a corresponding result for $C^{*}$-algebras generated by free semicircular systems: the isomorphism class of a $C^{*}$-algebra generated by a semicircular $n$-tuple does not depend on $n\in\{2,3,\dots,+\infty\}$. Similarl...

Dima Shlyakhtenko · 1 citation
Preprint Sep 2026

Dynamical $\mathrm C^*$-algebras and coarse geometry

Both the uniform Roe algebras and the quasi-local algebras encode the large scale geometry of metric spaces. Whether these algebras coincide is a question which goes back to Roe and has only been recently solved by Ozawa. We propose a dynamical point of view on this problem. Given a set $X$, every map $h\colon X\to\mat...

Bruno de Mendonça Braga · 0 citations
Preprint Oct 2026

Braid group invariance of quantum tori and applications

We establish that the skew-symmetric bicharacter on the group of $\ell$-weights of a quantum affine algebra is invariant under Chari's braid group action. Furthermore, we define an extension of this bicharacter to the group generated by prefundamental $\ell$-weights and show that this invariance continues to hold under...

F. Paganelli · 0 citations

We use cookies to run the site and, with your consent, for analytics and to show ads. See our Cookie Policy.