Dark matter detection closer as LIGO’s potential boosted 10,000 times

It’s been a long time since Fritz Zwicky, a Swiss astronomer, introduced the term ‘dark matter’ to the world in 1930. Over the last nine decades, our understanding of space and cosmic entities has advanced significantly. 

Yet one thing remains unchanged — dark matter was a mystery then, and it still is today. 

However, findings from a new study promise to change that. The study authors propose that the Laser Interferometer Gravitational-Wave Observatory (LIGO) has the potential to detect scalar field dark matter, a form of dark matter made of ultra-light scalar boson particles.

LIGO is a physics observatory that detects gravitational waves. It was developed and deployed by researchers at Caltech and MIT in the early 2000s. This giant tool made headlines in 2015 when it confirmed the presence of gravitational waves for the first time.

Here is how LIGO can observe the invisible dark matter

The theoretical ultralight boson particles that make up the scalar field dark matter are believed to interact with matter and light. Although this interaction is weak, it can result in the dark matter showing wave-like properties.

According to the researchers, LIGO can harness the wave-like patterns of the particles to detect scalar-field dark matter. “Some theories suggest dark matter behaves more like a wave than a particle,” Dr. Alexandre Sébastien Göttel, lead study author and a research associate at Cardiff University, said.  

“These waves would cause tiny oscillations in normal matter, which can be detected by gravitational wave detectors (such as LIGO),” Göttel added. He and his team also tested this theory using a theoretical model. 

This model examined a possible interaction between scalar field dark matter waves and LIGO with the help of simulation software, which predicted how scalar field dark matter might affect LIGO’s output. 

This analysis helped them identify the signals they should look for in LIGO’s data. Next, they studied LIGO’s data using a technique called logarithmic spectral analysis to find patterns within the signals that could indicate the presence of scalar field dark matter.

The results of the simulation

Although the researchers couldn’t find strong evidence of the dark matter, they were able to establish new upper limits on the coupling strength, i.e., how strongly dark matter could interact with the LIGO components. 

The new limits represented a 10,000-fold improvement in the coupling strength value compared to what was proposed by earlier studies. 

“We set new upper limits for the coupling constants of scalar field dark matter as a function of its mass, which improves upon bounds from previous direct searches by up to four orders of magnitude in a frequency band from 10 to 180 Hz,” the study authors note.

These findings suggest that LIGO has a greater chance of detecting dark matter than various other approaches. 

Moreover, as detectors more advanced than LIGO are developed, scientists will be able to test various scalar dark matter theories without applying any indirect search method.

The study is published in the journal Physical Review Letters.