Universal Bound States with Bose-Fermi Duality in Microwave-Shielded Ultracold Molecules

Area of Science:

• Quantum physics
• Ultracold atomic and molecular physics
• Quantum chemistry

Background:

• Ultracold molecules are crucial for studying quantum phenomena due to their strong interactions.
• Microwave shielding is a technique used to control interactions in ultracold molecules.
• Understanding few-body and many-body physics in molecular systems is a key challenge.

Purpose of the Study:

• To investigate the formation and properties of universal bound states in microwave-shielded ultracold molecules.
• To explore the role of dipolar interactions and microwave coupling in few-molecule systems.
• To examine the emergence of Bose-Fermi duality and self-bound droplet formation in molecular ensembles.

Main Methods:

• Theoretical modeling of few-molecule scattering in three dimensions under a highly elliptic microwave field.
• Development of effective one-dimensional (1D) models to describe molecular interactions.
• Calculation of bound states and Born-Oppenheimer potentials for tetratomic and hexatomic systems.

Main Results:

• Universal bound states were found to depend solely on dipolar interaction and microwave coupling strengths.
• Effective 1D models accurately reproduced tetratomic bound states and Born-Oppenheimer potentials.
• Hexatomic systems exhibited significantly deeper bound states, and Bose-Fermi duality was observed due to effective 1D scattering with a repulsive core.
• Large molecule ensembles are predicted to form elongated self-bound droplets with crystalline patterns.

Conclusions:

• Microwave shielding enables control over ultracold molecule interactions, leading to universal bound states.
• The study demonstrates the applicability of 1D models for complex 3D few-molecule systems.
• Bose-Fermi duality and self-bound droplet formation are significant emergent phenomena in ultracold molecular ensembles.