Scientists have learned a great deal about the universe, yet that knowledge represents only a small fraction of the full picture. Roughly 95% of the cosmos is made up of dark matter and dark energy, leaving just 5% as the familiar matter we can see around us. Dr. Rupak Mahapatra, an experimental particle physicist at Texas A&M University, is working to uncover this hidden majority by designing advanced semiconductor detectors equipped with cryogenic quantum sensors. These technologies support experiments around the world and are helping researchers push deeper into one of science’s greatest mysteries.

Mahapatra compares humanity’s limited understanding of the universe – or lack thereof – to a well-known parable. "It’s like trying to describe an elephant by only touching its tail. We sense something massive and complex, but we’re only grasping a tiny part of it."

Mahapatra and his co-authors recently had their work featured in the respected journal Applied Physics Letters.

What Are Dark Matter and Dark Energy?

Dark matter and dark energy are named for what scientists do not yet know about them. Dark matter makes up most of the mass found in galaxies and galaxy clusters, playing a major role in shaping their structure across vast cosmic distances. Dark energy refers to the force behind the universe’s accelerating expansion. Put simply, dark matter acts like cosmic glue, while dark energy drives space itself to expand faster and faster.

Although both are abundant, neither dark matter nor dark energy gives off, absorbs, or reflects light, which makes direct observation extremely difficult. Scientists instead study their influence through gravity, which affects how galaxies move and how large-scale structures form. Dark energy is the dominant component, accounting for about 68% of the universe’s total energy, while dark matter contributes roughly 27%.

Detecting Whispers in a Hurricane

At Texas A&M, Mahapatra’s research group is developing detectors with extraordinary sensitivity. These instruments are designed to detect particles that interact with ordinary matter only on rare occasions, interactions that could provide critical clues about the nature of dark matter.

"The challenge is that dark matter interacts so weakly that we need detectors capable of seeing events that might happen once in a year, or even once in a decade," Mahapatra said.

His team played a role in a leading global dark matter search using a detector known as TESSERACT. "It’s about innovation," he said. "We’re finding ways to amplify signals that were previously buried in noise."

Texas A&M is among a small group of institutions participating in the TESSERACT experiments.

Pushing the Limits of Detection

Mahapatra’s current efforts build on decades of experience in advancing particle detection methods. For the past 25 years, he has contributed to the SuperCDMS experiment, which has conducted some of the most sensitive dark matter searches in the world. In a landmark 2014 paper published in Physical Review Letters, Mahapatra and his collaborators introduced voltage-assisted calorimetric ionization detection in the SuperCDMS experiment – a breakthrough that made it possible to study low-mass WIMPs, a leading dark matter candidate. This advance significantly improved scientists’ ability to detect particles that had previously been beyond reach.

In 2022, Mahapatra co-authored another study examining multiple approaches to finding a WIMP, including direct detection, indirect detection and collider searches. The work highlights the importance of combining different strategies to tackle the dark matter problem.

"No single experiment will give us all the answers," Mahapatra notes. "We need synergy between different methods to piece together the full picture."

Understanding dark matter goes far beyond academic curiosity. It could reveal fundamental principles that govern the universe itself. "If we can detect dark matter, we’ll open a new chapter in physics," Mahapatra said. "The search needs extremely sensitive sensing technologies and it could lead to technologies we can’t even imagine today."

What Are WIMPs?

WIMPs (Weakly Interacting Massive Particles) are considered one of the most promising possibilities for dark matter. These hypothetical particles would interact through gravity and the weak nuclear force, which explains why they are so difficult to detect.

• Why they matter: If WIMPs exist, they could account for the universe’s missing mass.
• How we search: Experiments such as SuperCDMS and TESSERACT rely on ultra-sensitive detectors cooled to nearly absolute zero to capture rare interactions between WIMPs and ordinary matter.
• The challenge: A WIMP could pass through Earth without leaving any sign at all, meaning researchers may need years of data to identify even a single event.