Thermally Assisted Supersolidity in a Dipolar Bose-Einstein Condensate

TL;DR

This paper explores how finite temperature influences the stability and phase boundaries of supersolidity in dipolar Bose-Einstein condensates, revealing temperature as a key control parameter for experimental realization.

Contribution

It provides a comprehensive finite-temperature phase diagram of dipolar BECs, incorporating quantum and thermal fluctuations, and demonstrates temperature-driven pathways for supersolid formation and stability.

Findings

Finite temperature shifts supersolid phase boundaries to larger scattering lengths.

Thermal fluctuations lower the density threshold for supersolidity.

Moderate thermal fluctuations stabilize otherwise unstable single-droplet states.

Abstract

Supersolidity in a dipolar Bose-Einstein condensate (BEC), which is the coexistence of crystalline density modulation and global phase coherence, emerges from the interplay of contact interactions, long-range dipole-dipole forces, and quantum fluctuations. Although realized experimentally, stabilizing this phase at zero temperature often requires high peak densities. Here we chart the finite-temperature phase behavior of a harmonically trapped dipolar BEC using an extended mean-field framework that incorporates both quantum (Lee-Huang-Yang) and thermal fluctuation effects. We find that finite temperature can act constructively: it shifts the supersolid phase boundary toward larger scattering lengths, lowers the density threshold for the onset of supersolidity, and broadens the stability window of modulated phases. Real-time simulations reveal temperature-driven pathways (crystallization upon heating and melting upon cooling) demonstrating the dynamical accessibility and path dependence of supersolid order. Moreover, moderate thermal fluctuations stabilize single-droplet states that are unstable at zero temperature, expanding the experimentally accessible parameter space. These results identify temperature as a key control parameter for engineering and stabilizing supersolid phases, offering realistic routes for their observation and control in dipolar quantum gases.