Iceberg Quantum cuts its RSA-2048 factoring estimate to about 48,000 qubits in simulations
Short answer: Iceberg Quantum published Pinnacle 1.2 on 22 October 2026, saying direct circuit-level simulations show its Pinnacle architecture can reach logical error rates low enough to factor a 2048-bit RSA key, at a spacetime cost about an order of magnitude lower than its Pinnacle 1.0 estimate. Under its most favourable assumptions (physical error rate of 10-4 and a 1 microsecond code cycle), the company estimates about 48,000 physical qubits and an expected runtime of 0.98 days.
The result rests on a new decoder for QLDPC error-correcting codes called Crevasse, which Iceberg says takes four microseconds on average per round of error correction. Using it, the company says it processed trillions of simulated error-correction instances and directly observed a logical error rate below one error per trillion logical qubit-cycles, without extrapolation.
Iceberg says smaller codes than it previously assumed are enough, cutting space overhead by about 40% and time overhead by about 30% versus Pinnacle 1.0. It also says it compiled and verified a complete modular exponentiation circuit, the core of Shor's factoring algorithm, and counted the operations directly.
The estimates vary widely with hardware speed and quality. Iceberg's table gives 72,000 qubits and 3.7 days at a 10-3 error rate with a 1 microsecond cycle, and 714,000 qubits (29 days) to 2.1 million qubits (32 days) with a 1 millisecond cycle. For fixed-connectivity superconducting systems, its Frozen Pinnacle variant comes to about 99,000 qubits and 5.0 days, the company says.