Thread by @KonstantHacker

1. Topological quantum computing is here! This thread explains how Microsoft’s Majorana 1 works and what it will mean for a fault tolerant future. I was invited to Azure Quantum Labs and got to hold this amazing new chip!

2. Nature released a paper validating how Microsoft achieved this by creating a new state of matter--a stack of indium arsenide and aluminum built one atom at a time. This is a topoconductor or topological superconductor.

3. Majorana Zero Modes (MZMs) are created on the topoconductor, storing quantum information based on whether an odd or even number of electrons are present. To measure odd or even, a digital switch couples the ends of the nanowire to a quantum dot. Microwaves reflect off the dot.

4. The qubits, called tetrons due to a 4-ended, H-like shape, are less error prone. Expect low error-correction ratios of physical to logical qubits. The Majorana 1 chip has a 4x2 array of tetrons. Each qubit is 10 microns so the chip will hold a million qubits in ~2 centimeters.

5. There is an onboard controller on the chip (green, to right) allowing for easy I/O. Microsoft expects ~1000 logical qubits on one chip (gold center) without changing form factor of the Majorana 1 module. Onboard wiring included!

6. Look how everything fits in Majorana 1 with this amazing zoom out animation by Microsoft.

7. Microsoft believes the first killer application for such a machine will be in chemistry and other simulations of the quantum universe. DARPA believes in topological, having advanced Microsoft to the next stage of the US2QC program for creating a fault-tolerant system.

8. Check out today's episode of The Post-Quantum World podcast for a deep dive on Majorana 1 with Chetan Nayak from Microsoft.

9. YouTube Link to today's episode of The Post-Quantum World. It's available on all platforms, featuring an interview with Chetan Nayak from Microsoft, discussing Majorana 1.

For those interested in how Majorana 1 tetrons could scale, check out arxiv.org/abs/2502.12252