Ultracold Sticky Collisions: Theoretical and Experimental Status

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Chemical Physics

Background:

• Collisional complexes are transient intermediates in molecular interactions.
• Typically, these complexes decay within picoseconds.
• However, ultracold collisions involving bialkali molecules can form long-lived complexes (milliseconds).

Purpose of the Study:

• To review recent experimental and theoretical advancements in understanding ultracold molecular collisions.
• To address the phenomenon of "sticky" collisions and their impact on molecular samples.
• To investigate the behavior and lifetime of collisional complexes in molecule-molecule and molecule-atom interactions.

Main Methods:

• Review of recent experimental findings on ultracold molecular collisions.
• Analysis of theoretical models predicting collisional complex lifetimes.
• Examination of data from molecule-molecule and molecule-atom collision studies.

Main Results:

• Ultracold bialkali molecules form exceptionally long-lived collisional complexes.
• These "sticky" collisions lead to significant two-body loss in molecular samples.
• Observed complex lifetimes can exceed predictions from current theoretical models by orders of magnitude.

Conclusions:

• The long lifetimes of ultracold molecular collisional complexes present a challenge for creating dense, stable molecular samples, particularly in the quantum-degenerate regime.
• Further research is needed to fully understand the dynamics and behavior of these complexes.
• Understanding these "sticky" collisions is crucial for mitigating their detrimental effects and advancing ultracold molecule research.