Microsoft’s Majorana 1 quantum chip John Brecher/Microsoft In February, Microsoft unveiled a new quantum computer called Majorana 1 and it quickly became one of the most controversial devices in quantum computing. Majorana 1 caused controversy because it relies on a particular kind of quantum bit, or qubit, called a topological qubit. Theoretically, these are a lot more immune to errors than alternatives, making them an attractive proposition for building a largely error-proof quantum computer. For years, Microsoft has attempted to do just that, using elusive quasiparticles called Majorana zero modes (MZMs) as its basis for topological qubits – but its track record is mixed. In 2021, a paper by a group of Microsoft researchers was retracted from the scientific journal Nature after independent experts identified a flaw in the analysis that had aimed to establish the basic building block of topological qubits. Then, in 2023, an experiment concerning a predecessor to Majorana 1 was heavily criticised by several experts. As such, Microsoft’s 2025 Nature paper announcing Majorana 1 was always going to be heavily scrutinised. In …