This book studies the foundations of quantum theory through its
relationship to classical physics. This idea goes back to the Copenhagen
Interpretation (in the original version due to Bohr and Heisenberg),
which the author relates to the mathematical formalism of operator
algebras originally created by von Neumann. The book therefore includes
comprehensive appendices on functional analysis and C*-algebras, as
well as a briefer one on logic, category theory, and topos theory.
Matters of foundational as well as mathematical interest that are
covered in detail include symmetry (and its "spontaneous" breaking), the
measurement problem, the Kochen-Specker, Free Will, and Bell Theorems,
the Kadison-Singer conjecture, quantization, indistinguishable
particles, the quantum theory of large systems, and quantum logic, the
latter in connection with the topos approach to quantum theory.
This book is Open Access under a CC BY licence.