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Title: Matter-wave interference with particles above one million atomic mass units
Plain: The heaviest particles shown to interfere in a way classical physics cannot mimic weigh about 170,000 atomic mass units. Reaching a million or more, the mass of a small virus, requires slower beams and longer coherence.
Precise: Demonstrate near-field (Talbot-Lau) or far-field interference of neutral particles of mass $m \ge 1e6\,\mathrm{u}$ ($1.7e-18\,\mathrm{g}$) whose visibility versus grating power follows the quantum prediction and excludes the classical moire-shadow prediction at stated confidence, and report $\mu$. The 2025 analysis indicates metal clusters need velocities near $2.5e3\,\mathrm{cm}/\mathrm{s}$ in a $1e2\,\mathrm{cm}$ scale interferometer.
Settled by: A Talbot-Lau or vertical interferometer run with MDa clusters, nanoparticles or biomolecules in which quantum and classical predictions differ and the data follow the quantum one.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: In 2025 sodium clusters of 0.4 to 1 MDa gave high-visibility fringes, but at their velocities quantum and classical predictions coincide (arXiv:2507.21211).
Posed since: (empty)