Simultaneously Minimizing Storage and Bandwidth Under Exact Repair With Quantum Entanglement
2026-05-12 • Information Theory
Information TheoryNetworking and Internet Architecture
AI summaryⓘ
The authors study a way to store data across multiple nodes in a system that uses quantum entanglement to help repair failed nodes. They focus on exact repair, meaning the replaced node stores exactly the same data as before. Their work shows that the best known balance between storage size and repair bandwidth, previously found for approximate repairs, still holds when exact repair is required. They achieve this by combining classical coding techniques with quantum error-correcting code methods.
distributed storageexact repairentanglement assistanceregenerating codesCalderbank-Shor-Steane codesstabilizer formalismproduct-matrix codesquantum communicationrepair bandwidth
Authors
Lei Hu, Mohamed Nomeir, Alptug Aytekin, Sennur Ulukus
Abstract
We study exact-regenerating codes for entanglement-assisted distributed storage systems. Consider an $(n,k,d,α,β_{\mathsf{q}},B)$ distributed system that stores a file of $B$ classical symbols across $n$ nodes with each node storing $α$ symbols. A data collector can recover the file by accessing any $k$ nodes. When a node fails, any $d$ surviving nodes share an entangled state, and each of them transmits a quantum system of $β_{\mathsf{q}}$ qudits to a newcomer. The newcomer then performs a measurement on the received quantum systems to generate its storage. Recent work [1] showed that, under functional repair where the regenerated content may differ from that of the failed node, there exists a unique optimal regenerating point that \emph{simultaneously minimizes both storage $α$ and repair bandwidth $d β_{\mathsf{q}}$} when $d \geq 2k-2$. In this paper, we show that, under \emph{exact repair}, where the newcomer reproduces exactly the same content as the failed node, this optimal point remains achievable. Our construction builds on the classical product-matrix framework and the Calderbank-Shor-Steane (CSS)-based stabilizer formalism.