Series representation of quantum-field quasiprobabilities
H. M. Moya-Cessa, P. L. Knight · Physical Review A · 1993
The Wigner and Glauber-Sudarshan P functions for quantum fields are usually defined in terms of integrals over the phase space of characteristic functions. We show that they and, in general, any s-parametrized quasiprobability distribution may be represented as a series in terms of displaced number states facilitating a straightforward evaluation.