Insights into the Spread of Quantum ‘Magic’ in Large Systems

ML4Q associated member, Xhek Turkeshi, explores how “magic” —  which is essential for performing complex quantum computations — spreads and develops in systems of quantum bits (qudits). Magic helps quantify how much effort is needed to simulate quantum systems classically and is a key resource for quantum error correction. The researchers focus on how this magic spreads in random, complex quantum circuits (like brick-wall circuits) and introduce new ways to measure it that work for larger systems than ever before, up to 1024 qudits (previous studies only managed a dozen). They find that magic resources reach a balanced state over time, but at a different rate than entanglement entropy. Since these random circuits are simple models of chaotic systems, they suggest that their results could apply to a wide range of systems that behave chaotically.

Publication: Turkeshi, X., Tirrito, E. & Sierant, P. Magic spreading in random quantum circuits. Nat Commun 16, 2575 (2025).
DOI: https://doi.org/10.1038/s41467-025-57704-x