Środowiskowe Seminarium z Informacji i Technologii Kwantowych

In this talk, I will start by discussing the boson sampling problem and how it led to one of the first claims of an experimental demonstration of a quantum computational speedup. A boson sampler is a non-universal quantum computer that is able to interfere multiple photons over many optical modes and detect where the photons are at the output. A major source of imperfections in such devices comes from the fact that the photons are not exactly identical and have small differences in their internal degrees of freedom. I will discuss techniques that can be used to distinguish an ideal boson sampler and one involving partially distinguishable photons and require only an efficient classical postprocessing of the experimental data. Moreover, I will discuss the complex relation between the phenomenon of boson bunching and particle distinguishability, showing different situations where lower Hong-Ou-Mandel visibilities between the input photons can lead to higher bunching, contrary to common expectation.