Classical and quantum filaments in the ground state of trapped dipolar Bose gases

Abstract

We study by quantum Monte Carlo simulations the ground state of a harmonically confined dipolar Bose gas with aligned dipole moments, and with the inclusion of a repulsive two-body potential of varying range. Two different limits can be clearly identified, namely a classical one in which the attractive part of the dipolar interaction dominates and the system forms an ordered array of parallel filaments, and a quantum-mechanical one, wherein filaments are destabilized by zero-point motion, and eventually the ground state becomes a uniform cloud. The physical character of the system smoothly evolves from classical to quantum mechanical as the range of the repulsive twobody potential increases. An intermediate regime is observed, in which ordered filaments are still present, albeit forming different structures from the ones predicted classically; quantum-mechanical exchanges of indistinguishable particles across different filaments allow phase coherence to be established, underlying a global superfluid response.

Two-dimensional solitons and quantum droplets supported by competing self- and cross-interactions in spin-orbit-coupled condensates

“…In the case of the repulsive SPM, the LHY theory, which introduces effects of quantum fluctuations around the mean-field state, gives rise to post-mean-field corrections which are crucially important for the stabilization of self-trapped QDs by means of the effective higher-order self-repulsion [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. In particular, it removes the collapse induced by the attractive XPM at = N N thr , see equation (8).…”

“…The self-repulsive LHY terms may compensate the contact attraction between the components, which, otherwise, would destabilize the solitons due to the possibility of the collapse [32][33][34]. Furthermore, the LHY terms were predicted [35][36][37][38][39][40][41][42] and experimentally demonstrated (in the ultracold gas of dysprosium atoms) [44][45][46][47][48][49] to stabilize 2D and 3D self-trapped QDs supported by the long-range dipole-dipole interactions. In particular [35], developed a general formalism for adding small corrections to the mean-field equations.…”

Droplet Crystal Ground States of a Dipolar Bose Gas

“…Our results demonstrate that dipolar gases are an exciting dilute atomic system for studying supersolidity (cf. [18][19][20]). We also note recent work predicting a striped phase of a dipolar condensate in a cigar shaped trap potential [15].…”

Cluster stability driven by quantum fluctuations

“…To conclude, extending the present study, future work may address how similar complex structures can control quantum-mechanical exchanges, considering other two or multi-lengthscale soft-core potentials, possibly applicable in an experimental contest as, for instance, ultra-cold dipolar atoms [43][44][45][46][47][48][49] or supporting the understanding of other engaging systems such as quantum quasicrystals [50,51].…”