Published on: Jul 22, 2025

Coherent and Incoherent Light Scattering by Single-Atom Wave Packets

A single-atom, single-photon scattering experiment shows you can probe which-way information and coherence in free space without "trap-specific" effects being the deciding factor.

Quantum Measurement

Quantum Measurement

Light–Matter Interaction

Light–Matter Interaction

Ultracold Atoms

Ultracold Atoms

Quantum Optics

Quantum Optics

Researchers study how single photons scatter from single-atom wave packets in free space, framing results in terms of atom–photon entanglement and which-way information. Using ultracold atoms released from an optical lattice, they implement a thought-experiment-style interference test, then compare scattering before vs. during wave-packet expansion. They find the coherence properties of the scattered light don't depend on whether a trap is present, and argue several "trap-specific" effects aren't essential to the coherent vs. incoherent scattering question—highlighting atomic Mott insulators as a platform for precision fundamental tests.

DOI: 10.1103/zwhd-1k2t

Key Takeaways

Coherence vs. incoherence in light scattering is fundamentally about information/entanglement—not whether the atom is trapped.

  • Demonstrates a clean, controllable platform for quantum measurement / which-way questions using ultracold atoms.

  • Unifies "trapped atom" and "free-space wave packet" pictures by directly measuring scattering across wave-packet expansion.

  • Positions atomic Mott insulators as a practical source of high-quality single-atom wave packets for foundational experiments.

Institutions

Massachusetts Institute of Technology (MIT)

Cambridge, Massachusetts, United States

MIT Research Laboratory of Electronics (RLE)

Cambridge, Massachusetts, United States

MIT–Harvard Center for Ultracold Atoms

Cambridge, Massachusetts, United States

Journal

American Physical Society (APS)

Impact Factor: 9

Impact Factor: 9

Impact Factor: 9

Impact Factor: 9

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