Quantum enhancement of signal-to-noise ratio with a heralded linear amplifier

• DOI: 10.1364/optica.4.001421
• Publication Date: 2017-11-14T20:40:10Z
• Authors: Jie Zhao; Josephine Dias; Jing Yan Haw; Thomas Symul; Mark Bradshaw; Rémi Blandino; Timothy Ralph; Syed M. Assad; Ping Koy Lam
• Keywords: Linear amplifier; Quantum amplifier

Due to the pervasive nature of decoherence, protection quantum information during transmission is critical importance for any network. A linear amplifier that can enhance signals stronger than their associated noise while preserving coherence therefore great use. This seemingly unphysical property achievable a class probabilistic amplifiers does not work deterministically. Here we present amplification scheme realises this coherent states by combining heralded measurement-based noiseless and deterministic amplifier. The concatenation two introduces flexibility allows one tune between regimes high-gain or high noise-reduction, control trade-off these performances against finite heralding probability. We demonstrate an signal transfer coefficient $\mathcal{T}_s > 1$ with no statistical distortion output state. By partially relaxing demand Gaussianity, obtain further improvement achieve = 2.55 \pm 0.08$. Our only relies on optics post-selection algorithm. discuss potential using as building block in extending distance communication.