Beyond Lee-Huang-Yang description of self-bound Bose mixtures

Abstract

We investigate the properties of self-bound ultradilute Bose-Bose mixtures, beyond the Lee-Huang-Yang description. Our approach is based on the determination of the beyond mean-field corrections to the phonon modes of the mixture in a self-consistent way and calculation of the associated equation of state. The newly obtained ground state energies show excellent agreement with recent quantum Monte Carlo calculations, providing a simple and accurate description of the self-bound mixtures with contact type interaction. We further show numerical results for the equilibrium properties of the finite size droplet, by adjusting the Gross-Pitaevskii equation. Our analysis is extended to the one-dimensional mixtures where an excellent agreement with quantum Monte Carlo predictions is found for the equilibrium densities. Finally, we discuss the effects of temperature on the stability of the liquid phase.

Many-body and temperature effects in two-dimensional quantum droplets in Bose–Bose mixtures

“…( 10 ) predicts an imaginary sound velocity which may lead to a complex energy functional. Similar behavior has been reported in 22 , 27 for 3D droplets. In the Petrov’s work 1 , 13 , such a dynamically unstable phonon mode has been completely ignored under the assumption that its contribution is negligibly small.…”

“…Although this model which is based on the Petrov’s theory 13 gives reasonable results, it suffers from different handicaps. First, the generalized GPE disagrees with some experimental measurements 2 and quantum Monte Carlo (QMC) method 21 , 22 . In addition, it fails to properly predict the critical atom number 20 , 23 and to describe effects of quantum correlations 23 .…”

“…In addition, it fails to properly predict the critical atom number 20 , 23 and to describe effects of quantum correlations 23 . In this regard, many theoretical works beyond the generalized GPE have been introduced to study the properties of self-bound droplets 19 – 22 , 24 – 28 . Among them, the pairing theory 19 which has been used in order to improve the Petrov’s theory 13 for quantum droplets of 2D Bose mixtures.…”

Beyond-mean-field crossover from one dimension to three dimensions in quantum droplets of binary mixtures

“…The realization of quasi-1D droplets in the beyondmean-field crossover from 1D to 3D would allow precise studies of the beyond-mean-field effects in Bose gases. Effects beyond the standard Lee-Huang-Yang energy used in this paper will appear [27], either because of higherorder terms in the density expansion [28], because of finite-range interacting potentials [29,30], or because of temperature effects [31].…”

Self-Evaporation Dynamics of Quantum Droplets in a 41K-87Rb Mixture

“…These findings have triggered an intense research activity on droplets properties (see, e.g., the recent reviews in Refs. [16,17]) and on the so-called Lee-Huang-Yang fluid [18][19][20], and have motivated further studies in low-dimensional systems [21,22] and also beyond Petrov's theory [23][24][25][26][27].…”