  Two single-particle sources coupled in series to a chiral electronic
waveguide can serve as a probabilistic source of two-particle excitations with
tunable properties. The second-order correlation function, characterizing the
state of emitted electrons in space-time, is expressed in terms of the Floquet
scattering matrix of a source. It is shown that the Fourier transform of the
correlation function, characterizing the emitted state in energy space, can be
accessed with the help of an energy resolved shot-noise measurement. The
two-electron state emitted adiabatically is discussed in detail. In particular,
the two-electron wave function is represented via two different sets of
single-particle wave functions accessible experimentally.

Mesoscale and Nanoscale Physics