The photon wave function in optical solitons

The fabric of the nonlinear quantum field behind optical solitons suggests the many-particle structure of the photon wave function in optical solitons. This wave function derives from the bound states of the original quantum field and is found as the ground-state eigenfunction of a many-body Hamiltonian with a delta-function interaction potential. Drawing on the properties of such a many-particle photon wave function, we show how classical solitons with their signature hyperbolic secant field intensity profiles emerge from quantum nonlinear fields in the limit of very large photon numbers.