An experimental demonstration running two variational quantum algorithms -- a variational quantum eigensolver for the hydrogen molecule and a variational quantum factoring of semiprimes -- on a single reconfigurable, room-temperature silicon photonic integrated circuit. Four identical on-chip spontaneous-four-wave-mixing photon-pair sources (spiral waveguides) prepare two path-entangled ququarts whose correlations serve as the resource for preparing generic four-qubit trial states, with a classical optimizer iteratively tuning the interferometer phases to minimize each problem's cost function. Reported as the first realization of variational quantum algorithms on a photonic quantum simulator with integrated quantum-light sources, requiring no cryogenics.
Baldazzi, Sanna, Borghi, Azzini and Pavesi demonstrate two variational quantum algorithms running on a single reconfigurable room-temperature silicon photonic integrated circuit: a variational quantu…