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Atomic and molecular collision processes are the physical interactions of atoms and molecules when they are brought into close contact with each other and with electrons, protons, neutrons or ions. This includes energy-conserving elastic scattering and inelastic scattering. Such collisions are an important probe of the structure and properties of matter.
Evaporative cooling is the prevailing method for achieving ultracold temperatures in atomic systems, but the schemes to remove hotter atoms are limited by the spatial profile of the trapping potential. To overcome this limitation, the authors demonstrate a three-body recombination-based collisional cooling scheme for selective removal of hotter atoms.
Efimov states have very weak binding energy and show intriguing characteristics. Here the authors use high-resolution coherent spectroscopy to show the existence of an Efimov state embedded in the atom-dimer continuum for narrow Feshbach resonances in 7Li atoms.
While high-energy heavy ions create cylindrical damage zones called ion tracks in many materials, diamond was an exception for a long time. The authors have succeeded in creating the ion tracks in diamond utilizing 2−9MeV C60 fullerene ion irradiation and studied the structure of the tracks.
Ultracold polyatomic molecules can be created by electroassociation in a degenerate Fermi gas of microwave-dressed polar molecules through a field-linked resonance.
The high inelastic loss rate in gases of bosonic molecules has so far hindered the stabilization needed to reach quantum degeneracy. Now, an experiment using microwave shielding demonstrates a large reduction of losses for bosonic dipolar molecules.
A new binding mechanism between trapped laser-cooled ions and atoms has been observed. This advancement offers a novel control knob over chemical reactions and inelastic processes on the single particle limit.
The collective dynamics observed between Bose-condensed atoms and molecules indicate the occurence of macroscopic quantum phenomena. Experimental investigations found that the atomic and molecular populations oscillate at a frequency that scales with the sample size, providing evidence for bosonic enhancement. These findings could make many-body quantum dynamics accessible in ultracold molecule research.
Noble gas nuclear spins can store quantum information for hours but are hard to control. Creating a large coherent coupling to an alkali vapour gives a route to manipulating the collective nuclear spin of a helium-3 gas.
Controlling chemistry at the single-collision level is one of the main goals of experiments at ultralow temperatures. A method based on quantum logic techniques has now been shown to detect inelastic collisions in a hybrid ion–atom platform.
Cooling of trapped ions with a neutral buffer gas makes the study of atom–ion hybrid systems possible in the quantum regime. The new record low achieved opens the door to numerous opportunities, including full control over the atom–ion interactions.
Knowing which atomic, molecular and optical physics computer code to use and how is a challenge. Andrew Brown surveys the available software packages and discusses how code development practices in academia could be improved.