Nonstabilizerness and Error Resilience in Noisy Quantum Circuits

TL;DR

This paper studies how different types of noise affect nonstabilizerness in quantum systems, revealing that amplitude damping can create magic while depolarizing noise cannot, and that collective magic can be suppressed by realistic noise.

Contribution

It demonstrates that amplitude damping can generate or enhance magic in quantum systems, contrasting with depolarizing noise, and analyzes the collective behavior of nonstabilizerness under realistic noise conditions.

Findings

Amplitude damping can generate or enhance magic in quantum systems.

Depolarizing noise cannot generate nonstabilizerness.

Collective nonstabilizerness is suppressed by realistic incoherent noise.

Abstract

We investigate how noise impacts nonstabilizerness - a key resource for quantum advantage - in many-body qubit systems. While noise typically degrades quantum resources, we show that amplitude damping, a nonunital channel, can generate or enhance magic, whereas depolarizing noise provably cannot. In an encoding-decoding protocol, we find that, unlike in the coherent-noise case, a sharp decoding fidelity transition is not accompanied by a transition in nonstabilizerness. Although amplitude damping locally injects magic, this resource is washed out at the collective level after encoding, decoding, and postselection. Our results reveal that realistic incoherent noise can suppress many-body magic criticality even while generating it microscopically.