Towards a low entropy gas of fermionic polar molecules

Jacob P. Covey

José Paulo D'Incao, Chris H. Greene

Steven A. Moses, Jacob P. Covey, Matthew Miecnikowski +4 more

Ultracold polar molecules, with their long-range electric dipolar interactions, offer a unique platform for studying correlated quantum many-body phenomena. However, realizing a highly degenerate quantum gas of molecules with a low entropy per particle is challenging. We report the synthesis of a low-entropy quantum gas of potassium-rubidium molecules (KRb) in a three-dimensional optical lattice. We simultaneously load into the optical lattice a Mott insulator of bosonic Rb atoms and a single-band insulator of fermionic K atoms. Then, using magnetoassociation and optical state transfer, we efficiently produce ground-state molecules in the lattice at those sites that contain one Rb and one K atom. The achieved filling fraction of 25% should enable future studies of transport and entanglement propagation in a many-body system with long-range dipolar interactions.

Arghavan Safavi-Naini, Michael L. Wall, Ana María Rey

The preparation of a quantum degenerate gas of heteronuclear molecules has been an outstanding challenge. We use path-integral quantum Monte Carlo simulations to understand the role of interactions and finite temperature effects in the protocol currently employed to adiabatically prepare a low-entropy gas of polar molecules in a lattice starting from an ultracold Bose-Fermi mixture. We find that interspecies interactions affect the final temperature of the mixture after the adiabatic loading procedure and detrimentally limit the molecular peak filling. Our conclusions are in agreement with recent experimental measurements [Moses et al., Science 350, 659 (2015)] and therefore are of immediate relevance for the myriad experiments that aim to form molecules from dual-species atomic gases.

Ching-Kit Chan, Congjun Wu, Wei-Cheng Lee +1 more

Sebastian Will, Jee Woo Park, Cheng-Hsun Wu +3 more