Physicists have constructed the world’s first atomic vortex beam, a whirlwind of intriguing molecules and atoms with features still unknown.
Scientists could generate a swirling vortex by passing a straight beam of helium atoms through a grating with microscopic openings.
The extra oomph provided by the rotation of the beam, known as orbital angular momentum, provides it with a new direction to move in, allowing it to behave in ways that experts have yet to foresee. Because the electrons and nuclei inside the spiralling vortex atoms spin at different speeds, they believe the atoms’ rotation could add more dimensions of magnetism to the beam, as well as other unanticipated consequences.
“One possibility is that this could also change the magnetic moment of the atom, or the intrinsic magnetism of a particle that makes it act like a tiny bar magnet,” co-author Yair Segev, a physicist at the University of California, Berkeley, told Live Science.
In a classical atomic model, negatively charged electrons orbit around a positively charged atomic nucleus. But, according to Segev, as the atoms spin as a whole, the electrons within the vortex rotate faster than the nuclei, “creating different opposing [electrical] currents” as they twist.
According to Michael Faraday’s rule of magnetic induction, this could result in a slew of novel magnetic reactions, including magnetic moments flowing through the beam’s centre and out of the atoms, as well as other unanticipated results.
The researchers constructed the beam by transferring helium atoms to only 600 nanometers over a grid of small openings. Then, the whirling atoms came to a detector, showing that several beams, diffracted to varied angular momentum, printed on it like tiny small doughnut-like rings.
The scientists also found tiny, luminous rings of doughnut trapped inside the three central swirls. These are the obvious indications of helium excimers, created when one highly stimulated helium atom clings to another helium atom of the same energy.
According to Segev, the quantum mechanical “selection rules” that dictate how the whirling atoms interact with other particles are also changed by the orbital angular momentum imparted to atoms inside the spiralling beam. The scientists will then smash their helium beams against photons, electrons, and atoms of non-helium elements to examine how they react.
If the revolving beam responds differently, it could be an ideal pick for a new sort of microscope capable of gazing into unknown subatomic details. According to Segev, the beam could provide additional information on specific surfaces by modifying the image imprinted on the beam atoms.
“I think that as is often the case in science, it’s not a leap of capability that leads to something new, but rather a change in perspective,” Segev said.
The study was published in the journal Science.