There has been extensive discussion about how many qubits are required for a fault-tolerant
#quantumcomputer capable of demonstrating quantum utility. However, we should not overlook the fact that, for now, available quantum computers are not fully error-corrected. How far can we go under these conditions? We present a comprehensive analysis of how deep noisy quantum circuits can be for a broad class of physically reasonable noise channels. The key takeaway—spoiler alert—is that such circuits are logarithmically deep, in a precise average-case sense.
The glass may be seen as half full or half empty: the achievable circuit depth ultimately depends on the exact average gate fidelities. Nonetheless, it is important to recognize that these circuits will effectively be noise-induced shallow circuits, and they will not exhibit barren plateaus during training. I am delighted to share this work, authored together with the wonderful team of
@QuAntonioMele,
@acl_angrisani,
@soumik375,
@SumeetKhatri6,
@dsfranca, and
@quekpottheories, now published in
@NaturePhysics.