Q-Day Just Got Closer: Google's Algorithm Change Means Fewer Qubits Needed Than Expected

[StoneCold]

The Q-Day timeline just compressed significantly. Google's Craig Gidney published a paper showing that a quantum computer with fewer than one million noisy physical qubits could factor a 2048-bit RSA integer in less than a week. His previous estimate from 2019 required 20 million qubits. That's a 20x reduction in hardware requirements achieved entirely through algorithmic and architectural improvements. Not new hardware breakthroughs. Not exotic physics. Just smarter algorithms. This is the Q-Day story that matters most right now. The hardware milestone people were waiting for just got dramatically closer because the algorithm got dramatically smarter. Forrester's State of Quantum Computing 2026 report separately places Q-Day around 2030 based on current trajectory. That estimate looks increasingly plausible.

Q-Day Just Got Closer: Three Papers in Three Months Are Rewriting the Quantum Threat Timelinethequantuminsider.com

[BlackMamba]

20x reduction in qubit requirements through algorithm improvements alone is genuinely alarming. Hardware was the assumed bottleneck

[Luke_67]

The fact Google chose not to publish the actual circuits but released a zero-knowledge proof instead says something about how serious this is