Experimental demonstration of non-local magic in a superconducting quantum processor

Halima Giovanna Ahmad; Gianluca Esposito; Viviana Stasino; Jovan Odavic; Carlo Cosenza; Alessandro Sarno; Pasquale Mastrovito; Michele Viscardi; Stefano Cusumano; Francesco Tafuri; Davide Massarotti; Alioscia Hamma

arXiv · 2511.15576

Experimental demonstration of non-local magic in a superconducting quantum processor

Halima Giovanna Ahmad·Gianluca Esposito·Viviana Stasino·Jovan Odavic·Carlo Cosenza·Alessandro Sarno·Pasquale Mastrovito·Michele Viscardi·Stefano Cusumano·Francesco Tafuri·Davide Massarotti·Alioscia Hamma

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Abstract

Non-local magic is the non-stabilizerness that no local unitary operation can erase. It captures the joint action of entanglement and magic underlying quantum advantage, and it has never been measured on quantum hardware. Here we report its first experimental demonstration, on a superconducting quantum processing unit, through two independent routes: an optimal local-erasure protocol and a direct, state-agnostic measurement of subsystem purity. The two agree with each other and with theory. Exploiting direct access to the device, we construct a noise model with no free parameters that identifies readout error and a depolarizing controlled-Z channel as the dominant mechanisms, and we show that local and non-local magic can be addressed separately, erasing local magic in situ while preserving the non-local part. Non-local magic provides a hardware benchmark beyond standard gate-fidelity protocols and points toward more reliable pre-fault tolerant devices.The same tools underlie a purity-estimation protocol with exponential speedup and the decoding of Hawking radiation in a black-hole toy model.

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Halima Giovanna Ahmad, Gianluca Esposito, Viviana Stasino, Jovan Odavic, Carlo Cosenza, Alessandro Sarno, Pasquale Mastrovito, Michele Viscardi, Stefano Cusumano, Francesco Tafuri, Davide Massarotti, Alioscia Hamma. 2025-11-19. Experimental demonstration of non-local magic in a superconducting quantum processor. https://arxiv.org/abs/2511.15576

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