0000000000390822
AUTHOR
Mamoru Endo
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.
Phase Locking between Two All-Optical Quantum Memories.
Optical approaches to quantum computation require the creation of multi-mode photonic quantum states in a controlled fashion. Here we experimentally demonstrate phase locking of two all-optical quantum memories, based on a concatenated cavity system with phase reference beams, for the time-controlled release of two-mode entangled single-photon states. The release time for each mode can be independently determined. The generated states are characterized by two-mode optical homodyne tomography. Entanglement and nonclassicality are preserved for release-time differences up to 400 ns, confirmed by logarithmic negativities and Wigner-function negativities, respectively.
Generation of two-mode quantum states of light with timing controllable memories
We created and experimentally verified two-mode entangled states of light, α|0,1⟩ + βe*+|1,0⟩, by means of two phase-sensitive optical quantum memories. The release timing of each optical mode can be independently controlled for up to 400 ns.