What kind of jobs are there for someone with a strong, research-level theoretical background in the topic? I'm especially interested in the industry rather than academic jobs.
Let me try and give you a more focused answer. The good/promising news is this: there are many interesting and rewarding jobs available in the quantum technology industry. These jobs require a new type of skills, familiarity with quantum information processing, and these skills are in short supply. So you are not competing with vast numbers of new graduates from computer science.
Now "quantum logic" by itself is a foundational skill, you will need to build on that and show that you can be productive in the application of the rules of quantum mechanics to information processing. This could take a year of study, not more I think. I am quite confident that this is a viable route because of several students in my own group who have taken this route and have landed exciting jobs either in large industries (Google, Microsoft) or in small/medium-sized companies and start-ups.
It is extremely unlikely that you'll find an industrial employer who needs a problem solved in your particular academic sub-sub-specialty. And if by some miracle they do now, they won't next year. If you want employment in industry, you must be prepared to use your abilities to learn new things and solve mathematical problems in areas that you are not yet familiar with.
Here is a list of companies working on quantum computing. As this kind of company is a subclass of general IT companies, you will find all the regular roles of commercial IT:
- Evangelists, Sales
- Teachers (i.e. in an "academy" style function within the company, giving talks or courses of a few days each)
- Developers, Implementators
- Operations, Maintenance
As of 2021, quantum computing is still quite niche, in commercial terms. With your background you could be a worthwhile employee in all these aspects - fully depending on your own character and interests.
Also, as these companies probably are often small and enthusiastic startups, every person will probably work in more than one role at the same time, which can be great or not so great, depending on what you prefer.
If I were in your shoes, I'd send my resume, together with a clear message of what kind of work you want to do, and go job hunting. Treat it like an information retrieval operation; talk with possible employers, and ask them what kind of jobs they offer currently (or check the job offerings listed on their web sites, of course).
This will give you a very quick insight into what the market offers.