Generation of Quantum Entanglement based on Electromagnetically Induced Transparency Media

TL;DR

This paper proposes a more efficient scheme for generating quantum entanglement using electromagnetically induced transparency (EIT), enhancing continuous-variable entanglement and squeezing for quantum communication applications.

Contribution

A novel scheme introducing two-photon detuning in EIT to improve entanglement generation, demonstrating robustness and flexibility over traditional methods.

Findings

Enhanced entanglement with two-photon detuning

Maximum entanglement achievable at various Rabi frequencies

Scheme is robust over a range of optical depths

Abstract

Quantum entanglement is an essential ingredient for the absolute security of quantum communication. Generation of continuous-variable entanglement or two-mode squeezing between light fields based on the effect of electromagnetically induced transparency (EIT) has been systematically investigated in this work. Here, we propose a new scheme to enhance the degree of entanglement between probe and coupling fields of coherent-state light by introducing a two-photon detuning in the EIT system. This proposed scheme is more efficient than the conventional one, utilizing the dephasing rate of ground-state coherence, i.e., the decoherence rate to produce entanglement or two-mode squeezing which adds far more excess fluctuation or noise to the system. In addition, maximum degree of entanglement at a given optical depth can be achieved with a wide range of the coupling Rabi frequency and the two-photon detuning, showing our scheme is robust and flexible. It is also interesting to note that while EIT is the effect in the perturbation limit, i.e. the probe field being much weaker than the coupling field and treated as a perturbation, there exists an optimum ratio of the probe to coupling intensities to achieve the maximum entanglement. Our proposed scheme can advance the continuous-variable-based quantum technology and may lead to applications in quantum communication utilizing squeezed light.