Preferred basis without decoherence

TL;DR

This paper argues that the preferred basis problem in quantum measurement is not a real issue, as the apparatus's interaction Hamiltonian uniquely determines the measurement basis without relying on decoherence.

Contribution

It demonstrates that the apparatus itself, via its interaction Hamiltonian, selects a unique measurement basis independent of decoherence effects.

Findings

The apparatus's interaction Hamiltonian determines the measurement basis.

The preferred basis is uniquely selected by the apparatus, not decoherence.

The problem of preferred basis is not a fundamental issue in measurement theory.

Abstract

The aim of this paper is to argue that the "preferred basis problem" is not a real problem in measurement. We will show that, given an apparatus, among the infinite corrrelations that can be established in the final state by means of a change of basis, one and only one makes physical sense. It is the apparatus, through its interaction Hamiltonian, what selects a single basis and determines the observable to be measured, even without decoherence.