Generating Robust Entanglement via Quantum Feedback

TL;DR

This paper introduces a coherent feedback control scheme to enhance the robustness of entangled states generated by optical parametric oscillators, effectively reducing uncertainties and producing more reliable Gaussian entangled states.

Contribution

The paper presents a novel feedback control method that suppresses uncertainties in entanglement generation, improving the robustness of Gaussian entangled states.

Findings

Effective suppression of uncertainty in entanglement generation.

Enhanced robustness of two-mode squeezed states.

Improved stability of Gaussian four-mode cluster states.

Abstract

Generating entangled states is one of the most important tasks in quantum information technology. However, in reality any entanglement generator must contain some characteristic uncertainty, and as a result the produced entangled state becomes an undesirable mixed state. This paper develops a coherent feedback control scheme that suppresses the characteristic uncertainty of a typical entanglement generator (non-degenerate optical parametric oscillator) for producing robust Gaussian entangled states. In particular, we examine a two-mode squeezed state and Gaussian four-mode cluster states to demonstrate the effectiveness of the proposed control method.