Unity-Efficiency Parametric Down-Conversion via Amplitude Amplification

作     者：Murphy Yuezhen Niu Barry C. Sanders Franco N. C. Wong Jeffrey H. Shapiro 

作者机构：Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Physics Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Institute for Quantum Science and Technology University of Calgary Calgary Alberta T2N 1N4 Canada Program in Quantum Information Science Canadian Institute for Advanced Research Toronto Ontario M5G 1Z8 Canada Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Anhui 230026 China Shanghai Branch CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics University of Science and Technology of China Shanghai 201315 China Institute for Quantum Information and Matter California Institute of Technology Pasadena California 91125 USA 

出 版 物：《Physical Review Letters》 (物理评论快报)

年 卷 期：2017年第118卷第12期

页      面：123601-123601页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：Alberta Innovations National Science Foundation, NSF Physics Frontiers Center, (PHY-1125565) Air Force Office of Scientific Research, AFOSR, (FA9550-14-1-0052) Gordon and Betty Moore Foundation, GBMF, (GBMF-2644) Office of Naval Research, ONR, (N00014-13-1-0774) 

主　　题：Quantum algorithms Quantum state engineering Second order nonlinear optical processes 

摘      要：We propose an optical scheme, employing optical parametric down-converters interlaced with nonlinear sign gates (NSGs), that completely converts an n-photon Fock-state pump to n signal-idler photon pairs when the down-converters’ crystal lengths are chosen appropriately. The proof of this assertion relies on amplitude amplification, analogous to that employed in Grover search, applied to the full quantum dynamics of single-mode parametric down-conversion. When we require that all Grover iterations use the same crystal, and account for potential experimental limitations on crystal-length precision, our optimized conversion efficiencies reach unity for 1≤n≤5, after which they decrease monotonically for n values up to 50, which is the upper limit of our numerical dynamics evaluations. Nevertheless, our conversion efficiencies remain higher than those for a conventional (no NSGs) down-converter.