As we all know, Microsoft is primarily a software company and I regard their quantum software capabilities as quite strong.  Their recent announcement of the Quantum Development Kit and the Q# quantum programming language strengthened this impression.  Although it’s clear that they regard topological quantum technology as the long-term winning approach, there is still a lot of questions regarding risk, timing, and viability of a strategy that is banking on a qubit technology that so far has only been theoretical.

it seemed to me that a sensible strategy for them to pursue would for them to generate some early customer access and support a few of the existing non-topological quantum machines and then switch users to Microsoft’s own topological machines once they were ready.

Microsoft previously used a strategy like this in the early days of the PC.  After the initial IBM PC was introduced with the MS-DOS operating system, Microsoft entered into a partnership with IBM to create a next generation operating system called OS/2.  This allowed them to gain some more experience and obtain some revenue for a next generation operating system, but later on, Bill Gates switched development efforts to Microsoft Windows and, as they say, the rest is history.

However, recent hints shown by Microsoft now indicate that the topological qubit may not be as far off as we think.  Microsoft has started to use the word “imminent” in some recent interviews.   First, Dr. Krista Svore, Principal Research Manager of the Microsoft QuArC group, indicated that working topological prototype was imminent in a recent podcast posted on January 17th, and now Todd Holmdahl, Corporate Vice-President of Microsoft Quantum, used the term “imminently close” in an interview published on January 28th on the Financial Times web page.

Microsoft has been researching the topological quantum computer for over a decade now.  This concept is based upon a theoretical quasiparticle called a non-abelian anyon which can store a quantum state using a braiding effect.  Because the quantum state is implemented in the topology of the braid, small perturbations will not cause the quasiparticle to decohere and create logic errors.  This could provide a many orders of magnitude advantage in qubit quality over other approaches and make it much easier to scale a quantum computer to larger numbers of logical qubits.  While scientists are suggesting that a fully error corrected non-topological quantum computer may require a physical to logical ratio somewhere between 1000:1 and 10,000:1, a topologically based one may only require a ratio of 10:1 or less.  Microsoft has established significant partnerships with researchers at TU Delft, Niels Bohr Institute, University of Sydney, Purdue, University of Maryland, ETH Zurich and other institutions to develop this technology.

So if Microsoft can produce a real non-abelian anyon and demonstrate a working topological qubit, it would be a significant achievement and would like likely take a position at the top of our Qubit Quality charts.  For more information on Microsoft’s topological qubit efforts, you can view an article posted by Nature that you can find here.  Other organizations researching the topological qubit include Nokia Bell Labs and IBM.