Efficient conversion of closed-channel dominated Feshbach molecules of $^{23}$Na$^{40}$K to their absolute ground state

Abstract

We demonstrate the transfer of 23 Na 40 K molecules from a closed-channel dominated Feshbachmolecule state to the absolute ground state. The Feshbach molecules are initially created from a gas of sodium and potassium atoms via adiabatic ramping over a Feshbach resonance at 78.3 G. The molecules are then transferred to the absolute ground state using stimulated Raman adiabatic passage with an intermediate state in the spin-orbit-coupled complexOur measurements show that the pump transition dipole moment linearly increases with the closed-channel fraction. Thus, the pump-beam intensity can be two orders of magnitude lower than is necessary with open-channel dominated Feshbach molecules. We also demonstrate that the phase noise of the Raman lasers can be reduced by filter cavities, significantly improving the transfer efficiency.

Long-range interacting quantum systems

“…In the remaining part of the Section we decided to focus on Rydberg atoms for their recent applications to the spin systems with long-range and non-local interactions targeted by the present review, and therefore we are going to present the material needed for the subsequent sections only in relation to Rydberg systems. We will not extend further the discussion on the interactions and platforms on magnetic dipolar gases and polar molecules, for which we refer to the reviews (Baranov et al, 2012;Böttcher et al, 2020;Lahaye et al, 2009;Trefzger et al, 2011) for dipolar gases, (Bohn et al, 2017;Carr et al, 2009;Gadway and Yan, 2016;Moses et al, 2017) and recent developments (Bause et al, 2021;Matsuda et al, 2020; for polar molecules, even though we will anyway comment about these systems later in the text.…”

Transition from a polaronic condensate to a degenerate Fermi gas of heteronuclear molecules

“…Having established a means to efficiently create large ensembles of heteronuclear Feshbach molecules sets the stage for the creation of polar ground-state molecules. To achieve this, we coherently transfer the degenerate Fermi gas of 5 × 10 4 Feshbach molecules into the rovibronic ground state of the X 1 Σ + electronic manifold [37] with an overall efficiency of up to 60%. The momentum distribution is maintained during the transfer and is still fit well by a Fermi-Dirac distribution at a temperature of T = 0.28(3) T F .…”