New Laser Provides Ultra-Precise Tool for Scientists Probing the Secrets of the Universe

Estimated reading time: 4 minutes

The team's next goal is to use their laser to measure the first electron transition energy of a positively charged helium atom, called He+.
 
He+ is the one of the "holy grails" for testing QED, Eikema said, because the properties of the nucleus have been extensively studied, it can be trapped with electromagnetic fields and observed for a very long time, and the QED effects are larger in helium than in hydrogen.  
 
"If it's possible to measure this transition in He+, people will immediately do it, because it’s a very nice, clean transition," he said.
 
A test of QED in He+ might also help resolve the proton radius problem, a new puzzle gripping the physics community after complementary tests turned up conflicting measurements of the proton's size. The discrepancy could be due to a problem with QED theory, and so a better test would help scientists see whether or not QED theory still holds at this unprecedented new level of precision.
 
Going from molecular hydrogen to He+ is still an enormous jump, Eikema said, since the wavelength of light required is almost ten times shorter. If all goes according to plan, he estimates the team may have results to report in about 2 years.
 
"I went to a conference about the proton size problem and explained how we want to measure this transition of He+. Everyone was asking 'When? When? When?' They really want to know," Eikema said.
 
Sandrine Galtier, a postdoctoral researcher at Vrije University who will present the team's findings at the FiO meeting, says it's exciting how well their new laser system can test the extreme limits of theoretical physics.
 
"We don't need huge accelerators. With just a tabletop experiment, we can test the Standard Model of physics," she said.
 

• < Previous Page