The Quantum Issue: You Never Really Know The Future

What happened

Two major milestones have been reached since then that make a material difference in the likelihood of a viable quantum computer actually being produced sometime in the next decade or so. Bitcoin Magazine The Quantum Issue: You Never Really Know The Future People have been debating whether a quantum computer presents a realistic threat to the Bitcoin network for over a decade.

Error Correction Improvements The first major improvement has been in error correction. To account for the inherent noise in working with things at this kind of tiny scale, to get a logical qubit that is useful in computation in practice requires the use of multiple redundant physical qubits.

Each grid’s empty spaces need to be filled with check qubits. This check qubit requirement creates an extra overhead that can get close to 1,000 physical qubits per logical qubit in total, and it gets bad at scale because check qubits can only check on the qubits immediately next to them.

So every grouping of qubits needs to have checkers in equidistant spacing. This has allowed a 10x reduction in the amount of physical qubits necessary to produce a reliable logical qubit.