  We consider a typical realization of a qubit as a single particle in two-path
interferometric circuits built from phase shifters, beam splitters and
detectors. This framework is often taken as a standard example illustrating
various paradoxes and quantum effects, including non-locality. In this paper we
show that it is possible to simulate the behaviour of such circuits in a
classical manner using stochastic gates and two kinds of particles, real ones
and ghosts, which interact only locally. The model has built-in limited
information gain and state disturbance in measurements which are blind to
ghosts. We demonstrate that predictions of the model are operationally
indistinguishable from the quantum case of a qubit, and allegedly 'non-local'
effects arise only on the epistemic level of description by the agent whose
knowledge is incomplete due to the restricted means of investigating the
system.
