Nonstabilizerness, or magic, is a key quantum resource required for quantum computational advantage. Noise is typically viewed as purely detrimental because it drives quantum states toward classicality. However, the behavior of magic under realistic noisy dynamics remains poorly understood, in part due to the complexity of analyzing mixed-state magic.

 

In this talk, I will show that non-unital noise, exemplified by amplitude damping, can preserve and even inject magic into quantum states. Building on this observation, we present a proof-of-principle protocol that distills pure magic states using access to the noisy channel alone.

 

We then investigate the behavior of encoding–decoding quantum circuits under realistic noise models. Recent works suggest the presence of two distinct transitions. One transition separates a phase that is error-resilient, where the encoded logical state can be recovered, from a phase where recovery fails. The other transition was found to occur in the nonstabilizerness of the output states. We show that these two transitions do not coincide in general. In particular, while an error-resilience transition persists under realistic noise, we do not observe any transition in magic.

 

Finally, we discuss what features of a unitary ensemble allow it to sustain an error-resilient phase, shedding light on what makes a unitary "good" for protecting quantum information in the presence of noise.