3 papers
quant-ph2026
Two Operational Principles Single Out Quantum Theory
Kenji Nakahira
Quantum theory combines density matrices, Born probabilities, tensor-product composites, positive-operator-valued measures (POVMs), and quantum channels. In a finite-dimensional ca…
math.RA2024
Characterization of vector spaces by isomorphisms
Kenji Nakahira
A vector space is commonly defined as a set that satisfies several conditions related to addition and scalar multiplication. However, for beginners, it may be hard to immediately g…
quant-ph2023
A characterization of von Neumann entropy using functors
K. Nakahira
Baez, Fritz, and Leinster derived a method for characterizing Shannon entropy in classical systems. In this method, they considered a functor from a certain category to the monoid…