Nonlocality induced spread of phonon spectrum in the Gross-Pitaevskii model of BEC    [PDF]

Supratik Sarkar, A. Bhattacharyay
We add a minimal correction term to the local Gross-Pitaevskii equation to represent non-locality. Within the scope of Born approximation, we show that, the $\delta$-correlated interactions of the local Gross-Pitaevskii equation captures qualitatively correct features of the nonlocal scenario even when the s-wave scattering length is as large as the average separation of the particles in the dilute gas. We show that, the effective minimal nonlocality enhances the effective mass of particles in the kinetic energy part of the spectrum causing a spread of the phonon part of the Bogoliubov spectrum.
View original: http://arxiv.org/abs/1307.8231