Implementing quantum Fourier transform with integrated photonic devices

Many quantum algorithms that exhibit exponential speedup over their classical counterparts employ the quantum Fourier transform, which is used to solve interesting problems such as prime factorization [1]. Meanwhile, nonclassical interference of single photons achieved on integrated platforms holds the promise of achieving large-scale quantum computation with multiport devices [2]. An optical multiport device can be built to realize any quantum circuit as a sequence of unitary operations performed by beam splitters and phase shifters on path-encoded qudits. In this talk, I will present a recursive scheme for implementing quantum Fourier transform with a multimode interference photonic integrated circuit. \\[4pt] [1] P.W. Shor, SIAM J. Comput. 26, 1484-1509 (1997).\\[0pt] [2] A. Politi, M. J. Cryan, J. G. Rarity, S. Yu, J. L. O'Brien, Science 320, 646-649 (2008).