Angular spectrum influence and entanglement characterization of Gaussian-path encoded photonic qudits

TL;DR

This paper demonstrates the generation and characterization of entangled photonic qudits encoded in Gaussian transversal paths, analyzing how the pump beam profile influences their purity and entanglement.

Contribution

It introduces a method to generate entangled qubits and qutrits using Gaussian path encoding and provides a theoretical framework for controlling their entanglement via pump spectrum.

Findings

Generated high-purity, highly entangled states.

The pump angular spectrum influences state properties.

Experimental results confirm theoretical predictions.

Abstract

Entangled quantum states play an important role in quantum information science and also in quantum mechanics fundamental investigations. Implementation and characterization of techniques allowing for easy preparation of entangled states are important steps in such fields. Here we generated entangled quantum states encoded in photons transversal paths, obtained by pumping a non-linear crystal with multiple transversal Gaussian beams. Such approach allows us to generate entangled states of two qubits and two qutrits encoded in Gaussian transversal path of twin photons. We make a theoretical analyses of this source, considering the influence of the pump angular spectrum on the generated states, further characterizing those by their purity and entanglement degree. Our experimental results reveals that the generated states presents both high purity and entanglement, and the theoretical analysis elucidates how the pump beams profile can be used to manipulate such photonic states.