Periodic mean-field solutions and the spectra of discrete bosonic fields: Trace formula for Bose-Hubbard models
Periodic mean-field solutions and the spectra of discrete bosonic fields: Trace formula for Bose-Hubbard models
We consider the many-body spectra of interacting bosonic quantum fields on a lattice in the semiclassical limit of large particle number $N$. We show that the many-body density of states can be expressed as a coherent sum over oscillating long-wavelength contributions given by periodic, nonperturbative solutions of the, typically nonlinear, …