Abstract:

In semiconductor quantum optics the measurement of the correlation function g(2)(0)

In the second part of the talk I will extend the results to higher-order correlation functions g(k)(0).

The highly nonlinear and non-factorizable nature of correlation functions is one of the striking features of quantum physics, which in the last decade has become much more accessible thanks to more refined theory and experiments.

If g(k)(0) falls below the value it attains for the Fock state |k>, a nonzero lower bound for the projection of the density operator below k excitations can be derived. Likewise, for excluding vacuum from this subspace, one can still obtain a lower bound for the ratio between 1 to k-1 excitation and k to infinite excitations. In this context also an effective correlation function is derived. Finally, for large k, both the absolute and relative amplitudes approach a steady behaviour. We derive expressions for these values, which may even be used in all cases, as they are also lower bounds for finite k.