6–11 Dec 2026
Stellenbosch University
Africa/Johannesburg timezone

Quantum ring all-reduce: communication and privacy advantages for distributed learning

Not scheduled
20m
Jan Mouton Learning Centre (Stellenbosch University)

Jan Mouton Learning Centre

Stellenbosch University

Poster

Speaker

Maria Gragera Garces (University of Edinburgh)

Description

We show that a quantum communication layer enables provable advantages throughout the
distributed learning pipeline, regardless of the model's nature (classical or quantum).
Starting from ring all-reduce (the universal primitive for large-scale gradient
aggregation) we prove that pre-shared entanglement reduces per-link \emph{online} communication by a
provably optimal factor of two and enables information-theoretic private aggregation
impossible for any classical protocol. Beyond bandwidth and security, the same quantum setup gives advantages directly
relevant to training: for margin-based
alignment testing (\textsc{GapIP}$_\tau$), the quantum advantage is \emph{quadratic}
($\widetilde{O}(\tau^{-1}\log P)$ qubits vs.\ $\widetilde{O}(\tau^{-2})$ bits); and for
sign-consistency auditing against private parameter matchings
(\textsc{TieAudit}$_\varepsilon$), it is \emph{exponential} ($O(\varepsilon^{-2}\log P)$
qubits vs.\ $\Omega(\sqrt{P})$ bits).

Topic Other

Authors

Dr Lirandë Pira (NUS) Maria Gragera Garces (University of Edinburgh)

Presentation materials