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Jianshun Gao

Publications and source records attributed to Jianshun Gao.

2 recordsLinked to original sources

Competing triangular and stripe supersolid orders in a dipolar quantum gas

Supersolids are exotic quantum states in which long-range phase coherence coexists, and may interplay, with emergent spatial orders. A particularly rich phase diagram featuring several competing spatial orders is predicted for dipolar supersolids with two-dimensional crystals, yet the experimental observation of this structural variety has remained limited. Here we experimentally form competing triangular and stripe density-modulated states in a quantum gas of highly magnetic atoms confined in a surfboard-shaped trap by tuning contact interaction strength and dipole orientation. We define a structural order parameter and study its statistical behavior. Thereby, we identify both the triangular and stripe phases and the transition between them, the associated critical behavior being marked by enhanced non-Gaussian fluctuations. Furthermore, we observe each spatial structure in both the phase-coherent supersolid regime and the phase-incoherent insulating one, near and far from the unmodulated-to-modulated transition, respectively. Our results establish a versatile platform in which multiple phases of the two-dimensional-supersolid phase diagram, and more generally, intertwined symmetry-breaking phenomena, can be investigated.

cond-mat.quant-gas↗

A two-dimensional magneto-optical trap of dysprosium atoms as a compact source for efficient loading of a narrow-line three-dimensional magneto-optical trap

We report on a scheme for loading dysprosium atoms into a narrow-line three-dimensional magneto-optical trap (3D MOT). Our innovative approach replaces the conventional Zeeman slower with a 2D MOT operating on the broad 421-nm line to create a high-flux beam of slow atoms. Even in the absence of a push beam, we demonstrate efficient loading of the 3D MOT, which operates on the narrower 626-nm intercombination line. Adding push beams working at either 421 nm or 626 nm, significant enhancement of the loading rate is achieved. We reach the best performance, with an enhancement factor of $3.6$, using a push beam red-detuned to the 626-nm line. With loading rates greater than $10^8$ atoms/s achieved at a moderate oven reservoir temperature of $800\,^{\circ}$C, our method offers similar or greater performance than Zeeman-slower-based systems. Our 2D-MOT-based approach constitutes a promising first step for state-of-the-art quantum gas experiments with several advantages over the Zeeman-slower-based setup and is readily adaptable to other open-shell lanthanides.

physics.atom-ph↗