(Top) The outside of the apparatus for conducting Rabi-oscillation spectroscopy. (Lower left) The electronic components, including a high-precision sensor. (Lower right) A detailed microscopic image of the silicon sensor that makes the observations. Image: 2021 Torii et al.Physicists from Japan and the US have created a new way to observe details about the structure and composition of materials that improves upon previous methods.
In conventional spectroscopy, the frequency of light shining on a sample is varied over time to reveal details about it. The new technique, termed Rabi-oscillation spectroscopy, does not need to explore a wide frequency range, so can operate much more quickly. This technique, which the physicists describe in a paper in Physical Review A, could be used to interrogate current theories of matter in order to form a better understanding of the material universe.
Though they cannot be seen with the naked eye, everyone is familiar with the atoms that make up everything we see around us. Comprising collections of positive protons, neutral neutrons and negative electrons, atoms give rise to all the matter we interact with. But there are some more exotic forms of matter, including exotic atoms, which are not made from these three basic components. Muonium, for example, is like hydrogen, which has one electron in orbit around one proton, but it has a positively charged muon particle in place of the proton.
Muons are important in cutting-edge physics as they allow physicists to test their theories about matter, such as quantum electrodynamics or the Standard Model, with extremely high accuracy. This in itself is important, as only when a robust theory is pushed to its extremes may proverbial cracks start to appear, which could indicate where new, more complete theories are needed and even what form they might take. This is why the study of muonium is of great interest to the physics community, but up until now it has evaded detailed observation.
“Muonium is a very short-lived atom, so it is important to make quick observations with as much power as possible in order to obtain the best signal from the limited observation time,” said Hiroyuki Torii, an associate professor in the Graduate School of Science at the University of Tokyo, Japan. “Conventional spectroscopic methods require repeated observations across a range of frequencies to find the particular key frequency we are looking for, known as the resonance frequency, and this takes time.”
So, Torii and his team devised a new kind of spectroscopic method that makes use of a well-understood physical effect known as Rabi oscillation. Rabi-oscillation spectroscopy does not need to search for frequency signals in order to convey information about an atom. Instead, it looks at the raw sensor, or time-domain, data over a shorter amount of time and delivers information based on that, offering vast improvements in precision.
“The study of exotic atoms requires knowledge of low-energy atomic physics and high-energy particle physics. This combination of disciplines within physics suggests we’re on a path to a more complete understanding of our material universe,” said Torii. “I’m eager to see physicists use Rabi-oscillation spectroscopy to peer ever deeper into the world of exotic atoms containing unusual particles and isotopes, and other kinds of matter created at particle accelerators around the world.”
This story is adapted from material from the University of Tokyo, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.