Modeling sympathetic cooling of molecules by ultracold atoms

Abstract

We model sympathetic cooling of ground-state CaF molecules by ultracold Li and Rb atoms. The molecules are moving in a microwave trap, while the atoms are trapped magnetically. We calculate the differential elastic cross sections for CaF-Li and CaF-Rb collisions, using model Lennard-Jones potentials adjusted to give typical values for the s-wave scattering length. Together with trajectory calculations, these differential cross sections are used to simulate the cooling of the molecules, the heating of the atoms, and the loss of atoms from the trap. We show that a hard-sphere collision model based on an energy-dependent momentum transport cross section accurately predicts the molecule cooling rate but underestimates the rates of atom heating and loss. Our simulations suggest that Rb is a more effective coolant than Li for ground-state molecules, and that the cooling dynamics are less sensitive to the exact value of the s-wave scattering length when Rb is used. Using realistic experimental parameters, we find that molecules can be sympathetically cooled to 100$\mu$K in about 10s. By applying evaporative cooling to the atoms, the cooling rate can be increased and the final temperature of the molecules can be reduced to 1$\mu$K within 30s.

16 pages, 14 figures. Minor corrections picked up at proof stage

References in corpus (14)

• A High Phase-Space-Density Gas of Polar Molecules
• Ultracold dense samples of dipolar RbCs molecules in the rovibrational and hyperfine ground state
• Magneto-optical trapping of a diatomic molecule
• Creation of ultracold ${}^{87}$RbCs molecules in the rovibrational ground state
• Magneto-electrostatic trapping of ground state OH molecules
• Efficient all-optical production of large ${}^6$Li quantum gases using D${}_1$ gray-molasses cooling
• Improved magneto-optical trapping of a diatomic molecule
• Interactions and dynamics in Li + Li_2 ultracold collisions
• Large Effects of Electric Fields on Atom-Molecule Collisions at Millikelvin Temperatures
• Production of rovibronic ground state RbCs molecules via two-photon cascade decay
• Sympathetic cooling of polyatomic molecules with S-state atoms in a magnetic trap
• Cold atomic and molecular collisions: approaching the universal loss regime
• A high quality, efficiently coupled microwave cavity for trapping cold molecules
• Collision cross sections for the thermalization of cold gases

Cited by in corpus (34)

• Molecules cooled below the Doppler limit
• Radio Frequency Magneto-Optical Trapping of CaF with High Density
• Laser Cooling of Optically Trapped Molecules
• Sub-millikelvin dipolar molecules in a radio-frequency magneto-optical trap
• Magnetically-Trapped Molecules Efficiently Loaded from a Molecular MOT
• Magnetic trapping and coherent control of laser-cooled molecules
• Collisional Cooling of Ultracold Molecules
• Laser cooling of molecules
• Laser slowing of CaF molecules to near the capture velocity of a molecular MOT
• Strongly interacting ultracold polar molecules
• Laser cooled molecules
• An intense, cold, velocity-controlled molecular beam by frequency-chirped laser slowing
• Characteristics of a magneto-optical trap of molecules
• Spectroscopic characterization of aluminum monofluoride with relevance to laser cooling and trapping
• Collisions Between Ultracold Molecules and Atoms in a Magnetic Trap
• Trapping of molecular Oxygen together with Lithium atoms
• Quantum control of molecules for fundamental physics
• Accurate Determination of the Dynamical Polarizability of Dysprosium
• Atom-molecule collisions, spin relaxation, and sympathetic cooling in an ultracold spin-polarized Rb(${}^2\mathrm{S}$)-SrF${(}^2{\Sigma }^{+})$ mixture
• Principles and design of a Zeeman-Sisyphus decelerator for molecular beams
• Universal probability distributions of scattering observables in ultracold molecular collisions
• Molecular Collisions: from Near-cold to Ultra-cold
• Optimized cell geometry for buffer-gas-cooled molecular-beam sources
• One dimensional magneto-optical compression of a cold CaF molecular beam
• Ab Initio Study of Chemical Reactions of Cold SrF and CaF Molecules with Alkali-Metal and Alkaline-Earth-Metal Atoms
• Magnetic tuning of ultracold barrierless chemical reactions
• Thermalization in the Quantum Ising Model - Approximations, Limits, and Beyond
• Microwave trap for atoms and molecules
• Sympathetic cooling and slowing of molecules with Rydberg atoms
• Collisions in a dual-species magneto-optical trap of molecules and atoms
• The chemistry of AlF and CaF production in buffer gas sources
• Magnetic Feshbach resonances in ultracold atom-molecule collisions
• Restricted basis set coupled-channel calculations on atom-molecule collisions in magnetic fields
• The Li + CaF $\to$ Ca + LiF chemical reaction under cold conditions