Quantum properties of a non-Gaussian state in the large-N approximation

Understand

We study the properties of a non-Gaussian density matrix for a O(N) scalar field in the context of the incomplete description picture.

• This is of relevance for studies of decoherence and entropy production in quantum field theory.
• In particular, we study how the inclusion of the simplest non-Gaussian correlator in the set of measured observables modifies the effective (Gaussian) description one can infer from the knowledge of the two-point functions only.
• We compute exactly the matrix elements of the non-Gaussian density matrix at leading order in a 1/N-expansion.