We show that exchange symmetry in collisions of identical particles enables symmetry-protected coherent control of the total scattering cross section. For identical fermions, antisymmetrization enforces a common control phase among contributing channels within a given parity sector, yielding maximal control visibility. For identical bosons, phase locking persists but with reduced visibility due to additional exchange (satellite) contributions. Collisions of distinguishable particles lack this symmetry-imposed phase locking, leading to lower controllability and visibility. We elucidate these principles through coupled-channel quantum-scattering calculations for lithium–lithium collisions, comparing the ${}^6\mathrm{Li}-{}^6\mathrm{Li}$ (identical fermions), ${}^7\mathrm{Li}-{}^7\mathrm{Li}$ (identical bosons), and ${}^6\mathrm{Li}-{}^7\mathrm{Li}$ (distinguishable) systems. Furthermore, in the identical-particle cases, symmetry-enforced phase locking enables full control over the parity of the final state even beyond the ultracold regime. This mechanism is broadly applicable to identical-particle collisions, including homonuclear molecules for which established approaches—dc electric fields or microwave shielding—are ineffective or unavailable.

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• Chemical reactions
• Coherent control
• Cold and ultracold molecules
• Cold atoms & matter waves
• Scattering of atoms, molecules, clusters & ions
• Ultracold collisions