Long-lived and transient supersolid behaviors in dipolar quantum gases

Abstract

By combining theory and experiments, we demonstrate that dipolar quantum gases of both ${}^{166}$Er and ${}^{164}$Dy support a state with supersolid properties, where a spontaneous density modulation and a global phase coherence coexist. This paradoxical state occurs in a well defined parameter range, separating the phases of a regular Bose-Einstein condensate and of an insulating droplet array, and is rooted in the roton mode softening, on the one side, and in the stabilization driven by quantum fluctuations, on the other side. Here, we identify the parameter regime for each of the three phases. In the experiment, we rely on a detailed analysis of the interference patterns resulting from the free expansion of the gas, quantifying both its density modulation and its global phase coherence. Reaching the phases via a slow interaction tuning, starting from a stable condensate, we observe that ${}^{166}$Er and ${}^{164}$Dy exhibit a striking difference in the lifetime of the supersolid properties, due to the different atom loss rates in the two systems. Indeed, while in ${}^{166}$Er the supersolid behavior only survives a few tens of milliseconds, we observe coherent density modulations for more than $150$ms in ${}^{164}$Dy. Building on this long lifetime, we demonstrate an alternative path to reach the supersolid regime, relying solely on evaporative cooling starting from a thermal gas.

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Cited by in corpus (13)

• Supersolidity around a critical point in dipolar Bose Einstein condensates
• Rotating a supersolid dipolar gas
• Quantized vortices in dipolar supersolid Bose-Einstein condensed gases
• Feshbach Resonances in an Erbium-Dysprosium Dipolar Mixture
• Structured hetero-symmetric quantum droplets
• Berezinskii-Kosterlitz-Thouless Transition in Two-Dimensional Dipolar Stripes
• Probing the supersolid order via high-energy scattering: analytical relations among response, density modulation, and superfluid fraction
• Quantum correlations in dipolar droplets: Time-dependent Hartree-Fock-Bogoliubov theory
• Linear Response of a Periodically Driven Thermal Dipolar Gas
• Dipolar bosons in one dimension: the case of longitudinal dipole alignment
• Static-response theory and the roton-maxon spectrum of a flattened dipolar Bose-Einstein condensate
• Mixed-spin system with supersolid phases: Magnetocaloric effect and thermal properties
• Coherent spin mixing via spin-orbit coupling in Bose gases