Considerations on the collapse of the wavefunction

TL;DR

This paper explores how the wavefunction collapse in entangled photon systems affects ghost imaging, showing that assuming a mixed state collapse aligns models, while pure state assumptions lead to discrepancies.

Contribution

It provides a detailed analysis of the form of the collapsed wavefunction in entangled photon experiments, highlighting the importance of mixed states for model agreement.

Findings

Collapse into a mixed state aligns models with experimental predictions.

Collapse into a pure state results in significant model differences.

Correlated counting rate distributions support mixed state collapse assumptions.

Abstract

We investigate the specific form that the collapsed quantum state of a signal photon can take when its entangled idler is measured in an entangled ghost imaging configuration using a type II collinear phase matched spontaneous parametric downconversion (SPDC) interaction. Calculation of the correlated counting rate distributions in the ghost image plane and diffraction plane show that agreement between collapse and non-collapse models is obtained if the signal is assumed to collapse into a specific mixed state. However, if the signal is assumed to collapse into a pure state, significant differences arise between the predictions of the two collapse models.