Does Provable Absence of Barren Plateaus Imply Classical Simulability?

In this 46-minute talk from the Institute for Quantum Computing, Zoë Holmes from École Polytechnique Fédérale de Lausanne addresses a critical question in quantum computing: whether the structures that help avoid barren plateaus can also enable classical simulation of quantum systems. Explore the case-by-case analysis showing that many models with provable absence of barren plateaus are also classically simulable when classical data can be collected from quantum devices during an initial phase. Learn how barren plateaus stem from a curse of dimensionality, and how current solutions often encode problems into small, classically simulable subspaces. While acknowledging quantum computers' essential role in data collection, the presentation questions the information processing capabilities of many parametrized quantum circuits with barren plateau-free landscapes. The talk concludes by examining important caveats including limitations of average case arguments, smart initialization roles, models outside the presented assumptions, potential for superpolynomial advantages, and the possibility that larger quantum devices might outperform analytic expectations.