Extended Data Fig. 5: Evidence of the Goldstone mode in experimental and numerical data.
From: Measurement of the superfluid fraction of a supersolid by Josephson effect
a, Left panels, fluctuation of the clusters positions (black and green points) and centre of mass (pink points) of the supersolid for about 100 experimental shots. Right panel, histograms of the right-cluster (green) and of the centre-of-mass (pink) positions. b, Simulation of the Josephson dynamics coupled to the Goldstone oscillation. The position of the density minimum x0 (top row) shows a clear oscillation at the Goldstone frequency ωG ≪ ωJ. This lower frequency also appears in Z and Δφ (bottom row) on top of the standard Josephson dynamics.
