Quantum Computing Records & Answers
Reference pages computed from the same primary-source dataset and open model that power the interactive evaluator and the MCP server / API. Every number carries its date and source.
Answers
Common feasibility questions, each answered from the live dataset rather than from a fixed number.
Breaking RSA-2048 needs 1,399 logical qubits and, depending on the error-correction protocol, 1 to 6 million physical qubits. Computed from primary sources.
What is the lowest quantum gate error rate ever demonstrated?The record two-qubit gate error rate is 0.0003 (99.97% fidelity, Trapped-Ion). Full record history per platform, with primary sources and what the number leaves out.
What is the largest quantum computer by qubit count?The largest quantum computer has 1,180 physical qubits (Neutral Atom), per-platform record history with primary sources.
How many physical qubits does one logical qubit need?Error-correction overhead computed from primary sources: ~31.5 physical qubits per logical qubit for the best qLDPC code, 1,011–3,747 for the surface code.
What is a logical qubit?A logical qubit is an error-corrected qubit encoded across many physical qubits: ~31.5 with the best published qLDPC code, more with the surface code. Cost and capacity, from primary sources.
When will quantum computers be able to break RSA-2048?A dated, falsifiable extrapolation from sourced hardware records, not a prediction. Current record qubit counts are about 3.5 orders of magnitude short.
Records by platform
The best demonstrated two-qubit gate error rate and physical qubit count for each hardware type, with the full sourced history behind each figure.
Last updated 2026-09-15. All figures derive from primary, verified papers. Subscribe to receive updates.