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The next step is a superposition of two places farther apart than the bead's own size, confirmed by interference.","posed_since":"","precise":"For an optically or magnetically levitated dielectric particle of mass about $10^{-15} \\text{ to } 10^{-14}\\,\\mathrm{g}$ (radius $r \\sim 5 \\times 10^{-6} \\text{ to } 10^{-5}\\,\\mathrm{cm}$) prepared near its motional ground state, create a coherent spatial superposition or wave packet with coherence length exceeding $r$, and verify coherence by interference fringes or Wigner-function negativity, since position variance alone does not distinguish coherent from incoherent spreading.","problem_ref":"6c66ab1a106356b497801ed4117f947f1c83bf31fbbfb22c54b8cbab57fb20ba","references":"","settled_by":"Release-and-recapture or inverted-potential interferometry showing center-of-mass interference fringes from a separation larger than r.","status_note":"In 2024 a ground-state-cooled nanoparticle's coherence length was increased more than threefold (arXiv:2408.01264) and a pre-cooled nanoparticle's motional state was expanded beyond its size (arXiv:2408.09596); no interference fringes at separations above the particle size were found in the literature checked.","title":"Spatial superposition of a levitated nanoparticle larger than its 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