Conditions and experimental signatures of fragmentation in dipolar Bose-Einstein condensates

Determine the conditions that lead to fragmentation and identify the experimental signatures of fragmentation in dipolar Bose-Einstein condensates, accounting for roton-mode softening, modulational instability, beyond-mean-field effects, confinement, and quench protocols.

Background

The paper discusses fragmentation as the spontaneous breakdown of coherence into multiple uncorrelated phase substructures in dipolar Bose-Einstein condensates. Several mechanisms have been proposed, including roton-mode softening, modulational instability, and beyond-mean-field effects during nonequilibrium dynamics. Numerical studies based on extended Gross–Pitaevskii equations suggest that fragmentation may arise dynamically during droplet formation, particularly under confinement or quench protocols.

Despite these proposed mechanisms and numerical indications, the paper identifies the broader relationship between the physical conditions producing fragmentation and the experimentally observable signatures of that fragmentation as unresolved. This problem motivates the paper’s systematic examination of interaction competition, excitation spectra, superfluid fraction, and condensate fraction in quasi-one-dimensional dipolar condensates.