Experimental quantum entanglement and teleportation by tuning remote spatial indistinguishability of independent photons
Kai Sun, Yan Wang, Zhenghao Liu, Xiao-Ye Xu, Jin‐Shi Xu, Chuan‐Feng Li, Guang‐Can Guo, Alessia Castellini, Farzam Nosrati, G. Compagno, Rosario Lo Franco
Abstract
Quantitative control of spatial indistinguishability of identical subsystems as a direct quantum resource at distant sites has not yet been experimentally proven. We design a setup capable of tuning remote spatial indistinguishability of two independent photons by individually adjusting their spatial distribution in two distant regions, leading to polarization entanglement from uncorrelated photons. This is achieved by spatially localized operations and classical communication on photons that meet only at the detectors. The amount of entanglement depends uniquely on the degree of spatial indistinguishability, quantified by an entropic measure <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi class="MJX-tex-caligraphic" mathvariant="script">I</mml:mi> </mml:mrow> </mml:math> , which enables teleportation with fidelities above the classical threshold. The results open the way to viable indistinguishability-enhanced quantum information processing.