0000000000390825

AUTHOR

Petr Marek

0000-0002-5761-8966

Exploring a new regime for processing optical qubits: squeezing and unsqueezing single photons

We implement the squeezing operation as a genuine quantum gate, deterministically and reversibly acting `online' upon an input state no longer restricted to the set of Gaussian states. More specifically, by applying an efficient and robust squeezing operation for the first time to non-Gaussian states, we demonstrate a two-way conversion between a particle-like single-photon state and a wave-like superposition of coherent states. Our squeezing gate is reliable enough to preserve the negativities of the corresponding Wigner functions. This demonstration represents an important and necessary step towards hybridizing discrete and continuous quantum protocols.

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Vacuum Suppression in Gain-tuned Continuous-Variable Quantum Teleportation of a Single Photon by Conditioning on Sender

We experimentally demonstrate bolstering the strength of gain-tuned continuous variable quantum teleportation of a single photon by conditioning on the sender's measurement results to eliminate excess vacuum contamination in the output.

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Noiseless Conditional Teleportation of a Single Photon

We experimentally demonstrate the noiseless teleportation of a single photon by conditioning on quadrature Bell measurement results near the origin in phase space and thereby circumventing the photon loss that otherwise occurs even in optimal gain-tuned continuous-variable quantum teleportation. In general, thanks to this loss suppression, the noiseless conditional teleportation can preserve the negativity of the Wigner function for an arbitrary pure input state and an arbitrary pure entangled resource state. In our experiment, the positive value of the Wigner function at the origin for the unconditional output state, W(0,0) = 0.015 $\pm$ 0.001, becomes clearly negative after conditioning, …

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