2026/04/08 by David S. Simon, Christopher R. Schwarze, Anthony D. Manni +2 · 1 voice
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1007/s11128-026-05157-6
A particular type of linear optical multiport, the Grover four-port, has previously been shown to couple the spatial symmetry of a photon to its direction of travel. It is shown here that use of a nonstandard choice of qubit, based on symmetry, allows Grover four ports to act as compact, low-resource deterministic linear optical controlledNOTgates, with no post-selection or ancilla measurements required. This approach allows programmable devices, made from Grover multiports in combination with other standard optical components, that can implement multiple different one-, two-, and three-qubit gates, including the Fredkin and Toffoli gates.