Boson sampling with ultracold atoms in a programmable optical lattice

Abstract

Sampling from a quantum distribution can be exponentially hard for classical computers and yet could be performed efficiently by a noisy intermediate-scale quantum device. A prime example of a distribution that is hard to sample is given by the output states of a linear interferometer traversed by 𝑁 identical boson particles. Here, we propose a scheme to implement such a boson-sampling machine with ultracold atoms in a polarization-synthesized optical lattice. We experimentally demonstrate the basic building block of such a machine by revealing the Hong-Ou-Mandel interference of two bosonic atoms in a four-mode interferometer. To estimate the sampling rate for large 𝑁, we develop a theoretical model based on a master equation that accounts for particle losses, but does not include technical errors. Our results show that atomic samplers have the potential to achieve a quantum advantage over today's best supercomputers with 𝑁≳40.