Ultracold gases of dipolar Dy have emerged as platforms where studying novel phases of matter, such as liquid droplets, poses many questions since standard theoretical methods fail to account for some of their observed properties. Here we investigate the self-bound states of dipolar Dy condensates by using general Gaussian-state ansatzes which go beyond conventional coherent-state ansatzes by including multimode squeezing. Our theory provides a transition between self-bound liquid and gas phases that agrees well with experimental observations and additionally reveals an experimentally unexplored transition in the self-bound gas region from a coherent-dominated to a squeezed-dominated phase. Our theory also allows one to extract the real part of the three-body interaction strength of the Dy atoms from the particle number distribution of the condensates. This allows us to show that the self-bound states are stabilized by the short-range three-body repulsion. Our study sheds a different light onto the properties of self-bound droplets of Bose-Einstein condensates.

• Received 15 April 2020
• Accepted 26 August 2020

DOI:https://doi.org/10.1103/PhysRevResearch.2.043074

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society