Tomographic entanglement indicators in frequency combs and Talbot carpets

TL;DR

This paper demonstrates the effectiveness of tomographic entanglement indicators in continuous-variable systems, specifically in entangled Talbot carpets and biphoton frequency combs, offering simpler and direct entanglement assessment methods.

Contribution

The study applies tomographic entanglement indicators to CV systems, showing their advantages in analyzing entanglement in Talbot carpets and frequency combs, improving upon previous methods.

Findings

Tomographic indicators successfully assess entanglement in Talbot carpets.

Tomograms reveal clear entanglement signatures in biphoton frequency combs.

The approach simplifies entanglement detection compared to existing methods.

Abstract

Recent theoretical investigations on tomographic entanglement indicators have showcased the advantages of the tomographic approach in the context of continuous-variable (CV), spin and hybrid quantum systems. Direct estimation of entanglement using experimental data from the IBM quantum computing platform and NMR experiments have also been carried out in earlier work. A similar investigation in the context of CV systems is necessary to fully assess the utility of our tomographic approach. In this paper, we highlight the advantages of our approach in the context of experiments reported in the literature on two CV systems, namely, entangled Talbot carpets and biphoton frequency combs. We use the tomographic entanglement indicator to assess the extent of entanglement between a pair of Talbot carpets and demonstrate that this provides a simpler and more direct procedure compared to the one suggested in the experiment. We also establish that the tomograms corresponding to the two biphoton frequency combs carry clear entanglement signatures that distinguish between the two states.