Teleportation-based microwave-to-optical quantum transduction: The limited role of single-mode squeezing

Quantum transduction is an important building block for quantum networking. Although various platforms have been proposed, the efficiency of state-of-the-art systems is still way below the required threshold to provide robust quantum information transduction via a direct conversion approach. Increasing the efficiency via merely increasing the power of the pulsed pump will lead to heating that substantially reduces the repetition rate thus hinders the quantum information rate. In [Phys. Rev. Appl. 16, 064044 (2021)2331-701910.1103/PhysRevApplied.16.064044], we proposed a transduction paradigm based on continuous-variable quantum teleportation that shows a much higher rate in the low cooperativity region. While more recently [Phys. Rev. Res. 4, L042013 (2022)2643-156410.1103/PhysRevResearch.4.L042013] proposed to utilize microwave squeezing to assist direct conversion. In this work, we explore the role of squeezing in the teleportation-based transduction protocol via evaluating quantum capacity lower and upper bounds. Our analyses include both microwave squeezing and optical squeezing, and provide a systematical benchmark between the continuous variable teleportation-based approach and continuous variable direct conversion approach. We show that the enhancement from single-mode squeezing on the teleportation-based approach is limited, in contrast to the direct conversion case. In the low cooperativity region required by reasonable repetition rate, the teleportation-based protocol provides larger quantum information rate and fidelity of state transfer. At the same time, it takes substantial squeezing for direct conversion to get close to the teleportation-based approach, at the risk of potentially introducing additional heating from the pump.