# What is the area of physics/science called that deals with fundamental limits of computation?

I am interested in learning about the fundamental limits of computation and in particular would like to read textbooks on the subject if they exist. My background is in maths and computer science - I am certainly not looking for books on complexity theory.

Example questions I am looking to answer/be able to interpret:

1. What is the amount of energy required (as a fundamental limit) to divide two numbers?
2. What is the smallest volume of space which can retrievably store $$n$$ bits of data?
3. What is the fundamentally shortest running time of an algorithm with $$n$$ steps? (where steps are suitably defined by some fundamental physical definition of a computer)

I have heard of quantum-information theory, but I'm not sure that's precisely what I'm looking for.

• Computational complexity. – Lewis Miller May 30 at 17:28
• I don't see these questions well-formulated to have a single answer. For example, for question 1 you can have several devices from abacus to digital computers passing by analogic computers. – nicoguaro May 30 at 17:29
• My question explicitly states I'm not looking for books on complexity theory, I am interested in fundamental physical limits. As for varying devices, that is why the question is about fundamental limits. – campbellC May 30 at 17:53
• Something like this? – Jahan Claes May 30 at 18:42
• Computational complexity and Complexity theory are not the same. – Lewis Miller May 30 at 19:01