In the quest to understand the universe, scientists are continually uncovering new insights into its most enigmatic components: dark matter and dark energy. These elements constitute approximately 95% of the universe, leaving a mere 5% as “ordinary matter” — the stuff we can see and touch. Dr. Rupak Mahapatra, an experimental particle physicist at Texas A&M University, is at the forefront of this exploration. He designs advanced semiconductor detectors with cryogenic quantum sensors, which are pivotal in experiments around the globe, pushing the boundaries of our understanding.
Mahapatra compares our current grasp of the universe to an ancient 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.” His and his colleagues’ work is prominently featured in the esteemed journal Applied Physics Letters.
Decoding Dark Matter and Dark Energy
Dark matter and dark energy remain some of the most profound mysteries in cosmology. Dark matter, which makes up most of the mass in galaxies and galaxy clusters, is crucial in shaping their large-scale structure. Conversely, dark energy is the force propelling the universe’s accelerated expansion. In essence, dark matter holds the cosmos together, while dark energy drives it apart.
Despite their prevalence, these phenomena do not emit, absorb, or reflect light, rendering them nearly invisible to direct observation. Their gravitational influences, however, are evident in the formation and behavior of galaxies. Dark energy is even more dominant than dark matter, comprising about 68% of the universe’s total energy content, while dark matter accounts for roughly 27%.
Detecting Whispers in a Cosmic Hurricane
At Texas A&M, Mahapatra’s team is developing detectors so sensitive they can detect signals from particles that rarely interact with ordinary matter. These signals could unveil 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 explained.
The team has made significant contributions to a leading dark matter search using a detector named TESSERACT. “It’s about innovation,” Mahapatra noted. “We’re finding ways to amplify signals that were previously buried in noise.” Texas A&M is among a select group of institutions involved in the TESSERACT experiments.
Pushing the Limits of Detection
Mahapatra’s work builds on a legacy of pushing detection limits, particularly through his involvement in the SuperCDMS experiment over the past 25 years. In a groundbreaking 2014 paper published in Physical Review Letters, he and his collaborators introduced voltage-assisted calorimetric ionization detection in the SuperCDMS experiment. This breakthrough enabled researchers to probe low-mass WIMPs, a leading dark matter candidate, dramatically enhancing sensitivity for particles that were previously out of reach.
More recently, in 2022, Mahapatra co-authored a study exploring complementary detection strategies, including direct detection, indirect detection, and collider searches for WIMPs. This work highlights the global, multi-faceted approach required to solve the dark matter puzzle. “No single experiment will give us all the answers,” Mahapatra emphasized. “We need synergy between different methods to piece together the full picture.”
Understanding dark matter is not merely an academic exercise; it is crucial for unlocking the fundamental laws of nature. “If we can detect dark matter, we’ll open a new chapter in physics,” Mahapatra said. “The search requires extremely sensitive sensing technologies and could lead to innovations we can’t even imagine today.”
What Are WIMPs?
WIMPs, or Weakly Interacting Massive Particles, are among the most promising candidates for dark matter. These hypothetical particles interact through gravity and the weak nuclear force, making them incredibly elusive.
- Why they matter: If WIMPs exist, they could explain the missing mass in the universe.
- How we search: Experiments like SuperCDMS and TESSERACT employ ultra-sensitive detectors cooled to near absolute zero to detect rare interactions between WIMPs and ordinary matter.
- The challenge: A WIMP might pass through Earth without leaving a trace, requiring scientists to gather years of data to identify even a single event.
The announcement comes as scientists worldwide continue to push the boundaries of particle physics, seeking to uncover the secrets of the universe. The implications of these discoveries are vast, potentially leading to technological advancements and a deeper understanding of the cosmos.
