Resonantly Interacting Fermi-Fermi Mixture of ^{161}Dy and ^{40}K

Area of Science:

• Atomic physics
• Quantum simulation
• Condensed matter physics

Background:

• Ultracold atomic gases provide a versatile platform for simulating complex quantum phenomena.
• Creating mixtures of different atomic species with controlled interactions is crucial for exploring novel quantum states.

Purpose of the Study:

• To realize a Fermi-Fermi mixture of ultracold atoms combining mass imbalance, tunability, and collisional stability.
• To investigate the properties of such a mixture, particularly focusing on resonant interactions and their implications.

Main Methods:

• Utilizing an optically trapped sample of Dysprosium-161 (^161Dy) and Potassium-40 (^40K) atoms.
• Identifying a broad Feshbach resonance near 217 Gauss to tune interspecies interactions.
• Analyzing hydrodynamic expansion profiles and lifetime measurements.

Main Results:

• Successful realization of a mass-imbalanced Fermi-Fermi mixture.
• Observation of a broad Feshbach resonance enabling tunable interactions.
• Suppression of inelastic few-body processes by orders of magnitude due to the fermionic nature of the system.
• Bimodal behavior in hydrodynamic expansion attributed to mass imbalance.

Conclusions:

• The developed Fermi-Fermi mixture offers a stable and tunable platform for studying strongly correlated quantum systems.
• The suppression of inelastic collisions highlights the potential for long-coherence-time experiments.
• This system opens new avenues for exploring novel quantum states in mass-imbalanced fermionic systems.