Nighthawk

Current obstacles

Physics limits

• Noise caps circuit sizeWith roughly 1–3 errors per thousand two-qubit gates, a circuit of a few thousand gates builds up enough errors to drown the signal. Mitigation can recover results, but its cost grows exponentially with circuit size.
• Material defects shorten qubit lifeQubits lose their state within a few hundred microseconds, largely because of microscopic defects in surface oxides and junctions. No fabrication process yet removes them entirely.
• Classical simulation keeps catching upCircuits with limited entanglement can often be simulated on classical computers with tensor-network methods, so an advantage claim holds only for problems where entanglement grows quickly.