Bunching, clustering, and the buildup of few-body correlations in a quenched unitary Bose gas

Abstract

We study the growth of two-and three-body correlations in an ultracold Bose gas quenched to unitarity. This is encoded in the dynamics of the two-and three-body contacts analyzed in this work. Via a set of relations connecting many-body correlations dynamics with few-body models, signatures of the Efimov effect are mapped out as a function of evolution time at unitarity over a range of atomic densities n. For the thermal resonantly interacting Bose gas, we find that atombunching leads to an enhanced growth of few-body correlations. These atom-bunching effects also highlight the interplay between few-body correlations that occurs before genuine many-body effects enter on Fermi timescales.

Bose-Einstein condensation of Efimovian triples in the unitary Bose gas

“…1(b)), the beating phenomenon resembles the oscillation of the contact at the ground-state Efimov trimer frequency found in Ref. [40,44,45] and is analogous to the atom-dimer coherences observed in Ref. [65].…”

“…, quickly saturating as the system prethermalizes. This universal growth is approached in the zero-range limit of the triplet model, showing the expected secondary dependence on the Efimov effect at later times [45]. In Fig.…”

“…At early times, the formation of condensed triples follows sequentially the universal pair condensate growth, reflecting the hierarchical structure of the cumulant equations of motion (see [40,50]). At later times the dynamics depend strongly on the density regime, repeating log-periodically with the density typical of the Efimov effect [43][44][45]. In the trimer regime (Fig.…”

“…[33] reveal the existence of pair and triple condensates in the unitary Bose gas. Previous theoretical studies either have not included the necessary Efimovian correlations [37][38][39][40][41][42] or many-body effects [43][44][45], combined only recently in the triplet model of Ref. [46].…”

Scattering hypervolume for ultracold bosons from weak to strong interactions

“…When |a| diverges, Efimov predicted the existence of an infinite number of three-body bound states whose universal scaling properties have been observed experimentally [2][3][4][5][6][7][8]. This nonperturbative threebody effect influences the properties of strongly interacting Bose gases [9][10][11][12][13] and Bose-Einstein condensates (BECs) interacting with an impurity particle [14][15][16][17]. Connecting few-body processes with bulk properties of ultracold Bose gases is fundamental to our understanding of these quantum many-body systems.…”