The researchers performed thorough calculations to identify the slight attraction expected to form between atoms in this flood of electromagnetic.
After turning off the magnetic field, the atoms free-fell for around 44 milliseconds before arriving in the laser light field. They could be imaged using light sheet fluorescence microscopy.
The cloud spontaneously extended during the fall, allowing the researchers to collect data at various densities.
Maiwöger and colleagues discovered that at high densities, up to 18% of the atoms were missing from their observational photographs. They postulate that these absences resulted from collisions aided by light, which forced the rubidium atoms from their cloud.
The discovery illustrated a portion of what was going on. Light was scattering off other atoms, and the light coming in was having an impact on the atoms. The atoms acquired polarity when the light made contact with them.
Greater light intensity either attracted or repelled the atoms depending on the type of light employed. As a result, they were either drawn to an area of lower light or more light, and in both cases, they eventually gathered together.
“An essential difference between usual radiation forces and the [light triggered] interaction is that the latter is an effective particle-particle interaction, mediated by scattered light,” Maiwöger and colleagues write in their paper.
“It does not trap atoms at a fixed position (for example, the focus of a laser beam) but draws them toward regions of maximum particle density.”
Although the force pulling the atoms together is far smaller than the molecular forces we are more familiar with, it can still accumulate in vast sizes. Resonance lines and emission patterns, which astronomers use to help us understand celestial objects, may change as a result.
Additionally, it might clarify how molecules arise in space.
“In the vastness of space, small forces can play a significant role,” says Haslinger.
“Here, we were able to show for the first time that electromagnetic radiation can generate a force between atoms, which may help to shed new light on astrophysical scenarios that have not yet been explained.”