IBM has not announced a specific plan to build a million-qubit quantum computer. IBM's current largest quantum computer, as of 2023, is the IBM Quantum System One, which has 65 qubits. However, it's important to note that the field of quantum computing is rapidly evolving, and new advancements and announcements may have been made since then.
Quantum computing technology is progressing, and researchers and companies are continually working on increasing the number of qubits and improving their performance. It's difficult to predict the exact number of qubits that future quantum computers will have, as it depends on various factors such as technological advancements, engineering challenges, and the scalability of current qubit technologies.
It's worth mentioning that the number of "logical qubits" in a quantum computer can be different from the number of physical qubits. Logical qubits refer to qubits that are error-corrected or protected against errors using quantum error correction codes. These error correction schemes require additional physical qubits to encode and correct quantum information. The relationship between physical qubits and logical qubits depends on the specific error correction codes and implementations used.
To stay updated on the latest developments in quantum computing, it is advisable to refer to official announcements from IBM or follow the progress of the field through scientific publications and news sources.