Enlightening dark ions

January 12, 2021

Every field has its underlying principles. For economics it's the rational actor; biology has the theory of evolution; modern geology rests on the bedrock of plate tectonics.

Physics has conservation laws and symmetries. For instance, the law of conservation of energy - which holds that energy can neither be created nor destroyed -- has guided research in physics since antiquity, becoming more formalized as time went on. Likewise, parity symmetry suggests that switching an event for its mirror image shouldn't affect the outcome.

As physicists have worked to understand the truly bizarre rules of quantum mechanics, it seems that some of these symmetries don't always hold up. Professor Andrew Jayich focuses on investigating these symmetry violations in an effort to shed light on new physics. He and his lab members have just published a paper in Physical Review Letters reporting progress on synthesizing and detecting ions that are among the most sensitive measures for time (T) symmetry violations.

Time symmetry implies that the laws of physics look the same when time runs forward or backward. "For example, the path of a pool ball on a table simply retraces its course if the arrow of time is reversed," Jayich said. But that does not hold for all physical interactions.

Understanding when and why T symmetry breaks down could provide answers to some of the biggest open questions in physics, such as why the Universe is full of matter and lacks antimatter. "The laws of physics as we know them treat matter and antimatter on equal footing," Jayich said, "yet events in the early moments of the Universe favored matter over antimatter." These are tough problems to crack, with close to a century of work behind them.

To address these questions, Jayich and his team have controllably synthesized, trapped and cooled radioactive molecules, RaOCH3+ and RaOH+, that provide large improvements in sensitivity to T symmetry violation. First author Mingyu Fan, a doctoral student in Jayich's lab, discovered a technique to detect dark ions in their electromagnetic trap. These particles don't scatter light, which means the researchers can't detect them with a camera.

While adjusting some of the experimental parameters, Fan noticed the trapped ions, which normally sit very still, were oscillating rapidly at a large yet fixed amplitude. He figured out that this behavior provides a strong signal for detecting these elusive ions. "This controlled amplification of the motion allows us to measure the ion's motional frequency, and thus its mass precisely and quickly," Fan said.

Jayich and Fan reported their success in laser cooling radium ions in a previous study, which was the first to achieve this feat for the heavy element. The lab's recent breakthrough brings them closer to their ultimate goal of using radioactive molecules to test time symmetry violations.

The researchers used radium-226, which has 138 neutrons and no nuclear spin, in their recent work. They plan to use the slightly lighter isotope, radium-225, which has the necessary nuclear spin, in their planned symmetry violation experiments. Other members of the lab are working on efforts to laser cool and trap radium-225 ions and perform optical spectroscopy on the radioactive molecules that contain it.

"These results are a clear breakthrough for our planned 'big' experiments," said Jayich. "We have made these incredibly sensitive detectors, where a single molecule has the sensitivity to set new limits on T-violation. This opens up a new paradigm for measuring T-violation."
-end-


University of California - Santa Barbara

Related Antimatter Articles from Brightsurf:

Timing the life of antimatter particles may lead to better cancer treatment
Experts in Japan have devised a simple way to glean more detailed information out of standard medical imaging scans.

New calculation refines comparison of matter with antimatter
An international collaboration of theoretical physicists has published a new calculation relevant to the search for an explanation of the predominance of matter over antimatter in our universe.

Scientists make step towards understanding the universe
Physicists from the University of Sheffield have taken a step towards understanding why the universe is made of mostly matter and not antimatter, by studying the difference between the two.

Where did the antimatter go? Neutrinos shed promising new light
We live in a world of matter -- because matter overtook antimatter, though they were both created in equal amounts when our universe began.

T2K insight into the origin of the universe
Lancaster physicists working on the T2K major international experiment in Japan are closing in on the mystery of why there is so much matter in the universe, and so little antimatter.

Strongest evidence yet that neutrinos explain how the universe exists
New data throws more support behind the theory that neutrinos are the reason the universe is dominated by matter.

APS tip sheet: Origins of matter and antimatter
Study suggests an 'axiogenesis' mechanism for the explanation of the matter to antimatter ratio in the Universe

The axion solves three mysteries of the universe
A hypothetical particle called the axion could solve one of physics' great mysteries: the excess of matter over antimatter, or why we're here at all.

NASA's Fermi Mission links nearby pulsar's gamma-ray 'halo' to antimatter puzzle
NASA's Fermi Gamma-ray Space Telescope has discovered a faint but sprawling glow of high-energy light around a nearby pulsar.

Could the mysteries of antimatter and dark matter be linked?
RIKEN researchers and collaborators have performed the first laboratory experiments to determine whether a slightly different way in which matter and antimatter interact with dark matter might be a key to solving both mysteries.

Read More: Antimatter News and Antimatter Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.