Entangled photon pairs yield 10 percent more phase information in fibre
A peer-reviewed accepted manuscript reports a fibre-based experiment in which entangled photon pairs supplied 10 percent more Fisher information than a matched classical strategy. The calculation includes optical losses and detector inefficiency. The team converted polarization entanglement into energy–time entanglement and measured the output without selecting favourable events afterward. The journal has released an unedited early version.
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Photon pairs supply more information about phase
A peer-reviewed laboratory study by Romain Dalidet and colleagues found a 10 percent Fisher-information advantage using entangled photon pairs in an optical-fibre interferometer. Fisher information measures how much the observations reveal about phase. The comparison used a matched classical strategy and included unequal optical losses and detector inefficiency. EPJ Quantum Technology released the single study as an accepted, unedited manuscript, subject to further editing.[1]
The apparatus converts entanglement in photon polarization into energy–time entanglement, using a Mach–Zehnder-type arrangement at telecommunications wavelengths. A thermally stabilized enclosure and polarization controllers maintain the optical conditions. At the outputs, wavelength filters separate correlated photons before superconducting detectors register coincident arrivals. This reconstructs the detection probabilities without selecting a favourable subset of events afterward.[1]
The scan takes 20 seconds; lower losses remain important
Each phase point was measured for one second, giving a complete 20-point pattern in 20 seconds. Approximately 56,000 coincident events were detected each second. The reported 10 percent gain concerns Fisher information relative to the matched classical strategy; the apparatus remains below the separate absolute standard quantum limit. Lower overall losses are identified as important for further progress, while temperature, strain and rotation sensing are proposed applications.[1]
