Observation of anomalous decay of a polarized three-component Fermi gas

Abstract

Fermionic systems with multiple internal states, such as quarks in quantum chromodynamics and nucleons in nuclear matter, are at the heart of some of the most complex quantum many-body problems. The stability of such many-body multi-component systems is crucial to understanding, for instance, baryon formation and the nuclear structure, but these problems are typically challenging to tackle theoretically. Versatile experimental platforms on which to study analogous problems are thus sought-after. Here, we create a uniform three-component Fermi gas with controllable polarization, and observe anomalous decay of the polarized gas, in which the loss rates of each component unexpectedly differ, contradicting generic assumptions of three-body losses in this system. We introduce a generalized three-body rate equation which captures the decay dynamics, but the underlying microscopic mechanism is unknown. Three-component Fermi gases represent a versatile platform for quantum simulation, including quantum chromodynamics-like physics, pairing and few-body effects. Here the authors demonstrate control of spin imbalances and an unexpected asymmetric decay due to different three-body losses for each component, and whose microscopic mechanism remains to be understood.