An analytic formula determining quantum pointer basis and its application to a flying bullet

TL;DR

This paper introduces an analytic formula for determining the quantum pointer basis of macroscopic objects interacting with their environment, exemplified by a flying bullet, emphasizing robustness of the object state.

Contribution

It presents a novel, easily calculable analytic method for identifying the quantum pointer basis without relying on master equations or robustness against entanglement.

Findings

The formula successfully identifies pointer states of a flying bullet.

Pointer states have well-defined momentum and localized position.

Method simplifies analysis of macroscopic quantum systems.

Abstract

We propose a general scheme determining the quantum pointer basis of a macroscopic object interacting with environment. Unlike the decoherence program, our pointer basis does not require robustness against entanglement, but require robustness on the object state itself. The proposed pointer basis does not rely on master equations, and so is easily calculable since it has a time-local analytic formula. We show that, as a convincing example, the proposed formula gives an satisfactory pointer basis of a macroscopic flying body such as a bullet whose pointer states should have well-defined momentum as well as highly-localized position.