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Feshbach Resonance: Tuning Atomic Interactions

Interactive 3D simulator of a magnetic Feshbach resonance: sweep the field near an ultracold atomic scattering resonance and watch the scattering length diverge, atoms pair into shallow molecules, and the gas cross over from a repulsive to a bound-pair regime.

Quantum Physics3DAdvanced60 FPS📱 Mobile-adapted⇄ 2D version

A magnetic Feshbach resonance is the tool that turns an ultracold atomic gas into a fully tunable quantum system: sweeping an external magnetic field near the resonance pole drives the s-wave scattering length through zero and out to ±∞, switching the atoms between weak background interactions, a strongly interacting unitary regime, and a gas of shallow diatomic molecules. This simulator renders a box of atoms in 3D and computes the real Feshbach formula a(B) = a_bg(1 − Δ/(B−B0)) live from your field, width and background-length sliders, driving the atoms' capture radius and binding behaviour directly from that scattering length — cross the resonance and watch free atoms pair into gold, tethered molecules exactly where the physics says a shallow bound state should appear.

⚙ Under the hood

Sweep a magnetic field across an ultracold-atom Feshbach resonance and watch the s-wave scattering length diverge in real time, driving atoms from a weakly interacting gas into shallow bound molecules.

feshbach resonanceultracold atomsscattering lengthquantum gasmolecule formationmagnetic tuning

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install