Dark matter, which scientists estimate makes up about 85% of the universe's matter, remains one of the most mysterious components of the cosmos. Unlike visible matter-such as stars and planets-dark matter does not emit or reflect light, making it extremely difficult to detect. It is believed to act as an invisible glue that holds galaxies together, playing a critical role in the universe's structure and evolution.
Detecting dark matter has proven to be an immense challenge, as it does not interact strongly with conventional instruments. Among the theoretical particles proposed to form dark matter, the axion has emerged as a leading candidate. For decades, researchers have sought to detect axions or demonstrate that existing particles can mimic their behavior. NTU's research team has now achieved a significant milestone by confirming that photons-light particles-can exhibit axion-like properties under specific conditions.
Led by Professor Zhang Baile from NTU's School of Physical and Mathematical Sciences (SPMS), the team demonstrated that when photons travel through specially designed crystal structures, their movement mimics the behavior of theoretical axions. "The findings from our new crystal structures give us more confidence that we could one day use the crystals to detect real axions," said Prof Zhang. "Since axions are promising candidates for dark matter, our research might lay the groundwork for unravelling some of the universe's greatest mysteries."
The research, published in the journal Science on January 10, 2025, also points to potential advancements in communication technologies and quantum computing. The ability to manipulate photons in three dimensions using crystal structures could lead to more robust data transmission methods and more accurate quantum computers.
NTU's breakthrough centered on crystals made of yttrium iron garnet, a material with unique magnetic and optical properties. When photons passed through these layered crystal structures with alternating magnetic properties, they exhibited behavior consistent with axion theory. The photons moved in a single direction along the three-dimensional edges of the crystal without scattering or reversing direction, mimicking axions' theoretical movements.
The research builds on previous studies that explored how electrons might behave like axions, but these efforts were limited to two dimensions. Prof Zhang's team's focus on photons allowed them to simulate axion behavior in three dimensions, a crucial step forward.
Beyond dark matter detection, the study's findings could have practical applications in technology. The crystals' ability to guide photons along a specific path without being affected by imperfections could improve data transmission and reduce errors in quantum computing.
"These crystal structures are expected to become a practical tool for searching axion dark matter in the near future," said Professor Yannis Semertzidis of the Korea Advanced Institute of Science and Technology, who was not involved in the study. He highlighted the internal magnetic fields of the crystals as ideal for axion detection, calling the research a "promising alternative" to existing methods.
As the team continues its efforts to refine crystal designs and push the boundaries of particle physics, their work underscores the potential to unravel some of the universe's deepest secrets-one photon at a time.
Research Report:Photonic axion insulator
Related Links
Nanyang Technological University
Stellar Chemistry, The Universe And All Within It
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
