Preferred states of the apparatus

TL;DR

This paper investigates a simple one-dimensional model of a spin-1/2 system interacting with a position-momentum apparatus, revealing that certain initial apparatus states naturally favor measurement-like correlations without environmental decoherence.

Contribution

It demonstrates that specific initial states of the apparatus, such as localized Gaussian wavepackets, are preferred for establishing measurement-like correlations in a pure system-apparatus entangled state.

Findings

Localized Gaussian wavepackets are preferred apparatus states.

Measurement-like correlations can form without decoherence.

Pure entangled states exhibit preferred apparatus configurations.

Abstract

A simple one dimensional model for the system-apparatus interaction is analyzed. The system is a spin-1/2 particle, and its position and momentum degrees constitutes the apparatus. An analysis involving only unitary Schrodinger dynamics illustrates the nature of the correlations established in the system-apparatus entangled state. It is shown that even in the absence of any environment-induced decoherence, or any other measurement model, certain initial states of the apparatus - like localized Gaussian wavepackets - are preferred over others, in terms of the establishment of measurementlike one-to-one correlations in the pure system-apparatus entangled state.