Observer invariance of the collapse postulate of quantum mechanics

TL;DR

This paper investigates how the wave function collapse in quantum mechanics appears to different observers in relative motion, showing that while measurement efficiency varies, the orthogonality of outcomes remains invariant across reference frames.

Contribution

It demonstrates that the collapse postulate is observer invariant in terms of outcome orthogonality despite differences in measurement efficiency.

Findings

Observers agree on outcome orthogonality regardless of motion

Measurement efficiency differs between observers due to correlations

Collapse postulate maintains invariance in outcome structure

Abstract

We analyse the wave function collapse as seem by two distinct observers (with identical detectors) in relative motion. Imposing that the measurement process demands information transfer from the system to the detectors, we note that although different observers will acquire different amount of information from their measurements due to correlations between spin and momentum variables, all of them will agree about the orthogonality of the outcomes, as defined by their own reference frame. So, in this sense, such a quantum mechanical postulate is observer invariant, however the effective efficiency of the measurement process differs for each observer.