Quantum transduction via generalized continuous-variable teleportation
Phys. Rev. A 113, 012623 – Published 29 January, 2026
DOI: https://doi.org/10.1103/qwm4-8vxd
Abstract
Quantum transduction converts quantum states between different frequencies. Similarly, quantum teleportation transfers quantum states between different systems. While often appreciated for quantum communication between distant locations, teleportation can also operate between different frequencies. In terms of bosonic modes, quantum teleportation relies on two-mode squeezing, squeezed on the balanced Einstein-Podolsky-Rosen (EPR) quadratures, for entanglement and a balanced beam splitter plus homodyne detection for Bell measurement. Since cross-frequency-band entanglement is challenging to generate, we propose to enable transduction with teleportation while only relying on a conventional transduction device and narrow-band entanglement. Our insight is that a transduction device performs a cross-frequency-band beam splitter, almost what is needed in a Bell measurement, except that it is often not balanced. We resolve the issue by proposing a generalized teleportation protocol with arbitrarily unbalanced EPR quadratures and matched unbalanced beam splitters. The protocol can enhance quantum transduction, using only off-the-shelf components: intraband beam splitters, offline squeezing, homodyne detection, and displacements. The proposed protocol achieves perfect transduction when applied to a transduction device with an arbitrarily low efficiency, at infinite squeezing, and in the absence of extraction loss. A minimum squeezing in the range of [1.195,4.343] dB is needed to achieve quantum capacity enhancement.
