Generation of frequency entanglement with an effective quantum dot-waveguide two-photon quadratic interaction

TL;DR

This paper presents a theoretical model for a quantum dot-waveguide system that acts as a frequency entangling gate, enabling the generation of entangled photon states with potential applications in quantum information processing.

Contribution

It introduces a novel theoretical approach to shape a frequency entangling gate (FrEnGATE) using a quantum dot's four-level structure and analyzes its performance with continuous variable entanglement measures.

Findings

The FrEnGATE can generate high-quality frequency entanglement.

Trade-off identified between entanglement efficiency and quality.

The system can produce entangled frequency qudit states.

Abstract

Light-matter interactions with quantum dots have been extensively studied to harness key quantum properties of photons, such as indistinguishability and entanglement. In this theoretical work, we exploit the atomic-like four-level structure of a quantum dot coupled to a waveguide to model a shaping frequency entangling gate (FrEnGATE) for single photons. Our approach is based on the identification of input frequencies and an atomic level structure for which frequency-dependent one-photon transitions are adiabatically eliminated, while frequency-dependent two-photon transitions are resonantly enhanced. The frequency entanglement performance of the gate is analyzed using a Schmidt decomposition for continuous variables, revealing a trade-off between entanglement generation efficiency and entanglement quality. We further demonstrate the use of the FrEnGATE for the generation of entangled frequency qudit states.