Microsoft's latest quantum chip is 1,000 times more reliable than its predecessor — but why is it so controversial? - Keumars Afifi-Sabet, Live Science

Microsoft has revealed a new quantum computing chip with quantum bits (qubits) it says are capable of maintaining their quantum state for 1,000 times longer than its predecessor — paving the way for more reliable quantum computers by 2029. But not all scientists believe the company's claims. The experimental quantum processing unit (QPU), dubbed Majorana 2, features a four-qubit array that offers a reported mean qubit lifetime of 20 seconds and, in some instances, up to a minute. This is a massive improvement in quantum coherence times — the time that qubits are entangled so that calculations can run in parallel — typically seen in QPUs. Normally, this lifetime is measured in milliseconds (thousandths of a second). The new chip could put scientists on the path to building a quantum computer that's commercially viable by 2029 — halving the timespan researchers initially expected — Microsoft representatives said in a statement. 

https://www.livescience.com/technology/quantum/microsofts-new-quantum-chip-is-1-000-times-more-reliable-than-its-predecessor-but-why-is-this-new-chip-so-controversial