Quantum interference suppresses a resonance in ultracold lithium
Physicists observed signatures of an unusual molecular state in ultracold lithium collisions: quantum interference suppressed a resonance normally associated with scattering and loss. The peer-reviewed experiment distinguishes this effect from simply reducing atom losses. Agreement with calculations supports a long-standing theoretical mechanism, with a small residual coupling remaining in the real system.
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A molecular state persists among scattering states
Atoms usually form localized bound states below the energy needed for separation. Above that threshold, scattering can connect them to their surroundings and allow losses. A peer-reviewed lithium experiment observed signatures of an exception: interference between interaction pathways suppressed a collision resonance. The team identifies the molecular state with a mechanism in which destructive interference weakens its connection to the surrounding continuum of scattering states.[1]
Loss and elastic scattering separate the effects
The distinction emerged from comparing atom losses with elastic interactions, where collisions preserve the relevant total kinetic energy. In one region, both resonant signatures were suppressed. Elsewhere, losses fell while elastic interactions remained strong. Those outcomes matter because fewer missing atoms alone would not identify the interference-stabilized state. Complementary observations of the molecular state agreed with detailed calculations and a simpler theoretical description.[1]
Residual coupling bounds the interpretation
A small residual width remained in the real system because additional coupling channels were still present. The experiment therefore supports interference-based control of interactions and loss without measuring an infinite lifetime. The state was inferred from the disappearance of scattering signatures and agreement across measurements and theory. The demonstrated result belongs to an ultracold atomic system; practical quantum devices require their own evidence.[1]
