Excitations and stability of weakly interacting Bose gases with multibody interactions

Abstract

We consider weakly interacting bosonic gases with local and non-local multi-body interactions. By using the Bogoliubov approximation, we first investigate contact interactions, studying the case in which the interparticle potential can be written as a sum of N -body δ-interactions, and then considering general contact potentials. Results for the quasi-particle spectrum and the stability are presented. We then examine non-local interactions, focusing on two different cases of 3-body nonlocal interactions. Our results are used for systems with 2-and 3-body δ-interactions and applied for realistic values of the trap parameters. Finally, the effect of conservative 3-body terms in dipolar systems and soft-core potentials (that can be simulated with Rydberg dressed atoms) is also studied.

Long-range interacting quantum systems

“…Eq. ( 123) can be extended to the case of multibody interactions (Laghi et al, 2017). The spectrum is linear for small momenta and the slope defines the sound velocity of the system; for sufficiently large α (the specific value depends on the shape of the interaction) one recovers the usual roton-maxon spectrum that is common to other physical systems with non-local interactions as ultracold dipolar systems or superfluid 4 He.…”

Vortices in self-bound dipolar droplets

“…The recent observation of ultradilute self-bound droplets both in dipolar condensates [16][17][18][19][20][21][22], as well as in two-component Bose mixtures [23], together with a combined theoretical effort, established the importance of the fundamental role of quantum fluctuations in ultracold atomic systems [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. Yet, no work has investigated the presence and stability of vortex states in self-bound droplets in ultradilute liquids.…”