The bulk modulus of three-dimensional quantum droplets

TL;DR

This paper derives the bulk modulus of three-dimensional quantum droplets using theoretical and numerical methods, linking elasticity to particle number and interactions, and provides estimates for experimental reference.

Contribution

It introduces a theoretical and numerical analysis of the bulk modulus in quantum droplets, connecting elasticity with intrinsic vibrational modes and interaction parameters.

Findings

Derived the elastic bulk modulus of quantum droplets.

Established a relation between bulk modulus and vibrational eigenfrequencies.

Provided realistic estimates of the bulk modulus for experimental use.

Abstract

Quantum droplets (QDs), formed by ultradilute quantum fluids under the action of the Lee-Huang-Yang (LHY) effect, provide a unique platform for investigating a wide range of macroscopic quantum effects. Recent studies of QDs' breathing modes and collisional dynamics have revealed their compressibility and extensibility, which suggests that their elasticity parameters can be identified. In this work we derive the elastic bulk modulus (BM) of QDs by means of theoretical analysis and numerical simulations and establish a relation between the BM and the eigenfrequency of the QD's intrinsic vibrations. The analysis reveals the dependence of the QD's elasticity on the particle number and the strength of interparticle interactions. We additionally provide a realistic estimate of the bulk modulus for the system, yielding a concrete physical value that may serve as a reference for future experimental measurements. Taken together, these results also point to possibilities for realizing elastic media governed by the LHY effect.