Sign up ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

I have been thinking about Spekkens Toy model in terms of interfaces. The Spekkens paper concerns a physics based on only being able to receive answers to half the number of questions necessary to specify the state of a system. This is something like having a limited interface to some kind of system. I take an apparatus as an internal category in a monoidal category and the apparatus is seen as some limited interface to an underlying quantum causal structure. Would it be possible to reformulate Spekkens' idea in terms of internal categories?

share|cite|improve this question

1 Answer 1

up vote 4 down vote accepted

The short answer is yes: these ideas can be formulated as internal algebras in a monoidal category. Take a look at for starters. Bill Edwards' PhD thesis has quite a bit more, and other papers by him and Bob Coecke may also be of interest.

share|cite|improve this answer
Welcome to the site, Ross! –  Joe Fitzsimons Dec 11 '11 at 17:56
Thanks Joe. I've been lurking since (before!) it started :-) –  Ross Duncan Dec 11 '11 at 19:03

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.