Multiphoton Interference in Quantum Fourier Transform Circuits and Applications to Quantum Metrology
Zu-En Su, Yuan Li, Peter P. Rohde, He-Liang Huang, Xi‐Lin Wang, Li Li, Nai-Le Liu, Jonathan P. Dowling, Chao‐Yang Lu, Jian-Wei Pan · Physical Review Letters · 2017
Quantum Fourier transforms (QFTs) have gained increased attention with the rise of quantum walks, boson sampling, and quantum metrology. Here, we present and demonstrate a general technique that simplifies the construction of QFT interferometers using both path and polarization modes. On that basis, we first observe the generalized Hong-Ou-Mandel effect with up to four photons. Furthermore, we directly exploit number-path entanglement generated in these QFT interferometers and demonstrate optical phase supersensitivities deterministically.