Quantum computing records & answers

Base Error Rate: The probability of an error occurring during a single quantum operation (typically 10⁻³ to 10⁻² for current hardware).
Effective Error Rate: The cumulative probability that your quantum computation produces an incorrect result.
Quantum Error Correction: Techniques using multiple physical qubits to create more reliable logical qubits. The surface code threshold is approximately 1.4%.

Reference pages computed from the same primary-source dataset and open model that power the interactive calculator and the MCP server / API. Every number carries its date and source.

Answers

How many qubits are needed to break RSA-2048?
Breaking RSA-2048 needs 1,399 logical qubits and millions of physical qubits, computed from primary sources, with every assumption stated.
What is the lowest quantum gate error rate ever demonstrated?
The record two-qubit gate error rate is 0.0003 (Trapped-Ion), full per-platform record history with primary sources.
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: ~32 physical qubits per logical qubit for the best qLDPC code, 1,011–3,747 for the surface code.
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

Neutral Atom quantum computing records
Record two-qubit gate error rate 0.00136 and record physical qubit count 1,180, with full sourced history.
Superconducting quantum computing records
Record two-qubit gate error rate 0.000519 and record physical qubit count 1,121, with full sourced history.
Trapped-Ion quantum computing records
Record two-qubit gate error rate 0.0003 and record physical qubit count 98, with full sourced history.