Time-resolved boson sampling with photons of different colors

Interference of multiple photons via a linear-optical network has profound applications for quantum foundation, quantum metrology and quantum computation. Particularly, a boson sampling experiment with a moderate number of photons becomes intractable even for the most powerful classical computers, and will lead to "quantum supremacy". Scaling up from small-scale experiments requires highly indistinguishable single photons, which may be prohibited for many physical systems. Here we experimentally demonstrate a time-resolved version of boson sampling by using photons not overlapping in their frequency spectra from three atomic-ensemble quantum memories. Time-resolved measurement enables us to observe nonclassical multiphoton correlation landscapes. An average fidelity over several interferometer configurations is measured to be 0.936(13), which is mainly limited by high-order events. Symmetries in the landscapes are identified to reflect symmetries of the optical network. Our work thus provides a route towards quantum supremacy with distinguishable photons.Comment: 5 pages, 3 figures, 1 tabl

Bis[μ-4-amino-3,5-bis­(hydroxy­meth­yl)-1,2,4-triazole]bis{bis­[4-amino-3,5-bis­(hydroxy­meth­yl)-1,2,4-triazole]nickel(II)} tetra­nitrate methanol disolvate

The title complex, [Ni2(C4H8N4O2)6](NO3)4·2CH4O, contains a centrosymmetric binuclear nickel(II) complex bridged by a pair of 4-amino-3,5-bis­(hydroxy­meth­yl)-1,2,4-triazole ligands. The separation between the NiII atoms is 3.962 (1) Å. The Ni atoms are in a slightly distorted octa­hedral coordination. Inter­molecular N—H⋯O, N—H⋯N and O—H⋯O hydrogen bonds connect the ligands, solvent mol­ecules and nitrate ions