Quantinuum interview questions

The first 2 rounds progressed quickly until the third round whereby I was tasked to prepare a detailed strategy presentation. This comprised possible solutions to address Quantinuum's real business challenges including my 12-month work plan. I felt uncomfortable as it felt like providing free consulting work. However, I proceeded with the interview and the hiring manager seemed impressed. He promised for me to speak with other team members and their CHRO asap. The internal recruiter quickly followed up asking for my slide deck without mentioning any interview scheduling. My gut told me this is a big red flag so I declined since I already did an in-depth interview presentation. Then Quantinuum ghosted me.

The interview process took six months. I was recruited through LinkedIn by one of Quantinuum's in-house recruiters sometime during the second half of September. I had an initial video interview in early October, followed by 3 months of radio silence. Mid-January 2026, I heard from Quantinuum again, to set up an on-site interview at their location in Broomfield, CO. Their interviews are set up with groups, and last a whole day. I was interviewing with several groups throughout the day. Part of the interviewing process is giving a presentation based on something I had worked on, and was relevant to the position I was interviewing for. The position I was interviewing for is quite specialized: Principal / Lead Compiler Engineer. During my first interview in October 2025, I was told that Quantinuum was interested in improving the quality of their existing compiler. They claimed they were aware that the quality of their software was sub-par, and wanted to improve significantly on it. With great surprise, I learned that none of the interviewers for the second round had a background in Compilers. I was not asked a single compiler specific question during the full day on-site interview. One of the presentations I gave - I had several ready - was very specific to compilers. I was not asked a single compiler-related question during, or after I had finished presenting. It became very obvious to me during this on-site full-day interview that they did not know what they wanted, or what they were looking for. In spite of the fact that none of the interviewers had a compiler background, or a demonstrable track record in compiler development, several very strongly held opinions were offered about compiler construction and compiler development, with no track record to back them up. Makes me wonder what these opinions were based on. The afternoon session was management / behavioral. I was asked HR-type questions about what to do if there is a disagreement within the team, how do we reach consensus, etc. One of the interviewers was very shocked to hear me say that I am mature enough to be able to admit "I don't know, I have to look it up" when I'm faced with a question I don't know the answer to. I think I lost points on this one. I suspect the expected answer was "I'll fake it till I'll make it". That seems to be the Standard Operating Procedure these days. Two of my presentations contained code examples, along with explanations of what the code did, and how they related to compiler development. Some of the code is complex, and subtle. I did not get the impression that anyone understood any of the subtleties inherent in the code examples. One of the interviewers openly admitted "I cannot parse that code". I was not asked a single question about the code examples. I had to step through every single line of code explaining what it did. Overall, a very disappointing and frankly frightening experience. If this is the level of competence prevalent in Quantum Computing Development, it's no wonder that the largest integer that has been factorized to date, using Shor's Algorithm, is still 21 - as in 3 times 7. That's after 40+ years of Quantum Computing Research and Development and billions of dollars invested.