Fig. 5: Domain wall dynamics between the chequerboard and dimer states.
From: Observation of Hilbert space fragmentation and fractonic excitations in 2D
a, Depending on the interface orientation relative to the tilt (orthogonal, left; parallel, right), the dimers act as positive (green circles) or negative (red circles) defects in the chequerboard (grey area). At the interface, the upper atom in the dimers can propagate, whereas the lower atom stays at its original site. b, Mean density as a function of evolution time for the central 10 × 10 sites. We observe the emergence of a larger chequerboard area for the orthogonal orientation (top row), indicated by the black dashed line at t/τ = 40. For the parallel orientation, the chequerboard remains intact. c, Evaluating the data in the green and red triangular regions of interest (chosen such that there is an even, identical number of sites in both halves of the system; Methods) illustrated in b, we find that the overlap with the chequerboard (CHB) remains constant for the parallel orientation (red) whereas we observe an increase for the orthogonal orientation (green). d, For the orthogonal interface orientation (green), the imbalance in the chequerboard half of the system decays. For the parallel orientation (red), the imbalance stays consistent with the reference measurement of a pure chequerboard (grey). All error bars denote the standard error of the mean. ROI, region of interest.
