Seminario di Fisica statistica

by Turkeshi Xhek (University of Cologne)

Tuesday 17 Feb 2026, 14:00 → 16:00 Europe/Rome

Aula Conversi (Dip. di Fisica - edificio G. Marconi)

Quantum computing aims to harness uniquely quantum effects to achieve capabilities beyond the reach of classical machines. Realizing this vision at scale requires protecting fragile quantum information from noise. However, only a restricted set of operations can be implemented with fault tolerance, and many of them remain efficiently simulable on classical computers. This limitation can be overcome through quantum magic: a property of certain quantum states that enables operations outside the fault-tolerant, classically accessible set. Without magic, even a perfectly error-corrected quantum computer would offer no computational advantage. A central challenge is therefore not only to quantify magic, but to understand its collective behavior in large many-body systems, where complexity emerges dynamically. In this talk, I will argue that quantum magic admits a natural description in the language of statistical physics. Using replica methods, I will study how magic is generated and propagates in fault-tolerant Clifford circuits, and determine how much magic is required to drive a system into a genuinely chaotic, Haar-like phase. This perspective provides concrete tools to benchmark and validate quantum devices, while revealing intrinsic limits on what can be efficiently predicted or verified by physical observers constrained to classical resources.