The ultrametric Hilbert-space description of quantum measurements with a finite exactness

We provide a mathematical description of quantum measurements with a finite exactness. The exactness of a quantum measurement is used as a new metric on the space of quantum states. This metric differs very much from the standard Euclidean metric. This is the so-called ultrametric. We show that a finite exactness of a quantum measurement cannot he described by real numbers. Therefore, we must change the basic number field. There exist nonequivalent ultrametric Hilbert space representations already in the finite-dimensional case (compare with ideas of L. de Broglie). Different preparation procedures could generate nonequivalent representations. The Heisenberg uncertainty principle is a consequence of properties of a preparation procedure. The uncertainty principle “time-energy” is a consequence of the Schrödinger dynamics.