Limitations of Noisy Quantum Devices in Computational and Entangling Power

Understand

Finding solid and practical quantum advantages via noisy quantum devices without error correction is a critical but challenging problem.

• Conversely, comprehending the fundamental limitations of the state-of-the-art is equally crucial.
• In this work, we consider the class of strictly contractive unital noise and derive its analytical representation by decomposition.
• Under such noise, we observe the polynomial-time indistinguishability of $n$-qubit devices from random coins when circuit depths exceed $\Omega(\log(n))$.