Special matrices over finite fields and their applications to quantum error-correcting codes
Meng Cao
TL;DR
This work extends matrix-product codes by analyzing NSC-defining matrices $A$ with $AA^{\dag}$ $(D,\tau)$-monomial to enhance quantum code design. It derives a closed-form formula for the Hermitian hull dimension and furnishes necessary/sufficient conditions for MP codes to be Hermitian dual-containing (HDC), almost-Hermitian dual-containing (AHDC), Hermitian self-orthogonal (HSO), almost Hermitian self-orthogonal (AHSO), and Hermitian LCD. It further characterizes the τ≠$\mathbbm{1}_{k}$ case, providing explicit criteria and alternative AHDC/AHSO formulations, and presents both trivial and nontrivial construction methods for HDC/AHDC MP codes, including distance-lower-bound considerations. The results enable systematic design of MP-based quantum codes with desired dual properties and distance guarantees, and they quantify how constituent-code relations influence achievable code properties. Overall, the paper offers practical criteria and constructions to build robust quantum error-correcting codes via structured MP codes.
Abstract
The matrix-product (MP) code $\mathcal{C}_{A,k}:=[\mathcal{C}_{1},\mathcal{C}_{2},\ldots,\mathcal{C}_{k}]\cdot A$ with a non-singular by column (NSC) matrix $A$ plays an important role in constructing good quantum error-correcting codes. In this paper, we study the MP code when the defining matrix $A$ satisfies the condition that $AA^†$ is $(D,τ)$-monomial. We give an explicit formula for calculating the dimension of the Hermitian hull of a MP code. We provide the necessary and sufficient conditions that a MP code is Hermitian dual-containing (HDC), almost Hermitian dual-containing (AHDC), Hermitian self-orthogonal (HSO), almost Hermitian self-orthogonal (AHSO), and Hermitian LCD, respectively. We theoretically determine the number of all possible ways involving the relationships among the constituent codes to yield a MP code with these properties, respectively. We give alternative necessary and sufficient conditions for a MP code to be AHDC and AHSO, respectively, and show several cases where a MP code is not AHDC or AHSO. We provide the construction methods of HDC and AHDC MP codes, including those with optimal minimum distance lower bounds.
