Quadrature protection of squeezed states in a one-dimensional photonic topological insulator

TL;DR

This paper investigates how topological properties of a one-dimensional photonic lattice influence the propagation and robustness of squeezed quantum states, revealing topological protection of phase coherence beneficial for quantum information.

Contribution

It demonstrates that topologically protected states preserve the phase of squeezed quadratures during propagation, unlike trivial states, offering new avenues for quantum information processing.

Findings

Topologically protected states maintain phase coherence of squeezed light.

Squeezed states in topological states are robust against disorder.

Topological protection enhances quantum information protocols.

Abstract

What is the role of topology in the propagation of quantum light in photonic lattices? We address this question by studying the propagation of squeezed states in a topological one-dimensional waveguide array, benchmarking our results with those for a topologically trivial localized state, and studying their robustness against disorder. Specifically, we study photon statistics, one-mode and two-mode squeezing, and entanglement generation when the localized state is excited with squeezed light. These quantum properties inherit the shape of the localized state but, more interestingly, and unlike in the topologically trivial case, we find that propagation of squeezed light in a topologically protected state robustly preserves the phase of the squeezed quadrature as the system evolves. We show how this latter topological advantage can be harnessed for quantum information protocols.