@techreport{ab0c6ccc9c1f4feebb744593606725cc,

title = "Quantum interference enables constant-time quantum information processing",

abstract = " Science, medicine and engineering demand efficient information processing. It is a long-standing goal to use quantum mechanics to significantly improve such computations. The processing routinely involves examining data as a function of complementary variables, e.g., time and frequency. This is done by the Fourier transform approximations which accurately compute inputs of $2^n$ samples in $O(n 2^n)$ steps. In the quantum domain, an analogous process exists, namely a Fourier transform of quantum amplitudes, which requires exponentially fewer $O(n \log n)$ quantum gates. Here, we report a quantum fractional Kravchuk-Fourier transform, a related process suited to finite string processing. Unlike previous demonstrations, our architecture involves only one gate, resulting in constant-time processing of quantum information. The gate exploits a generalized Hong--Ou--Mandel effect, the basis for quantum-photonic information applications. We perform a proof-of-concept experiment by creation of large photon number states, interfering them on a beam splitter and using photon-counting detection. Existing quantum technologies may scale it up towards diverse applications. ",

keywords = "quant-ph",

author = "M. Stobi{\'n}ska and A. Buraczewski and M. Moore and Clements, {W. R.} and Renema, {J. J.} and Nam, {S. W.} and T. Gerrits and A. Lita and Kolthammer, {W. S.} and A. Eckstein and Walmsley, {I. A.}",

note = "44 pages, 7 figures",

year = "2018",

month = jul,

day = "11",

language = "English",

series = "Arxiv.org",

publisher = "arXiv.org",

type = "WorkingPaper",

institution = "arXiv.org",

}