Advanced quantum noise correlations
Ulrich Vogl and Ryan T Glasser and Jeremy B Clark and Quentin Glorieux and Tian Li and Neil V Corzo and Paul D Lett

New Journal of Physics 16, 013011 (2014)

New Journal of Physics 16, 013011  (2014)

We use the quantum correlations of twin beams of light to investigate the fundamental addition of noise when one of the beams propagates through a fast-light medium based on phase-insensitive gain. The experiment is based on two successive four-wave mixing processes in rubidium vapor, which allow for the generation of bright two-mode-squeezed twin beams followed by a controlled advancement while maintaining the shared quantum correlations between the beams. The demonstrated effect allows the study of irreversible decoherence in a medium exhibiting anomalous dispersion, and for the first time shows the advancement of a bright nonclassical state of light. The advancement and corresponding degradation of the quantum correlations are found to be operating near the fundamental quantum limit imposed by using a phase-insensitive amplifier.