One hundred years after Schrödinger introduced his game-changing equation, physicists are still chasing the holy grail: a unified theory that blends the bizarre world of quantum mechanics with the cosmic scale of general relativity.
At Utah State University, researchers are using a radical idea known as the holographic principle to bridge the gap. By crafting precise mathematical models, they’re venturing where experiments can’t reach—toward the very edges of spacetime and gravity.
Schrödinger’s Equation: A Quantum Leap in Physics
Exactly a century ago, Austrian physicist Erwin Schrödinger—yes, the “cat-in-a-box” guy—introduced an equation that would revolutionize science. Schrödinger’s Equation became one of the cornerstones of quantum mechanics, giving scientists a powerful tool to calculate the wave function of a system and how it changes dynamically in time.
“Quantum mechanics, along with Albert Einstein’s theory of general relativity, are the two pillars of modern physics,” says Utah State University physicist Abhay Katyal. “The challenge is, for more than half a century, scientists have struggled to reconcile these two theories.”
Reconciling Incompatible Realms
Quantum mechanics governs the weird world of atoms and subatomic particles. General relativity, on the other hand, explains how gravity works on massive objects like stars, planets, and galaxies. Both theories are incredibly successful in their own realms, but they clash when scientists try to apply them together.
“Many unknowns in physics are explained by one side or the other, but these explanations are often incompatible,” says Oscar Varela, associate professor and Katyal’s faculty mentor. “Quantum gravity is an attempt to combine these theories, but to this day, we don’t know what quantum gravity is.”
Utah Physicists Dive Into the Holographic Principle
In the quest toward finding the correct theory of quantum gravity, Varela and Katyal, with former USU postdoctoral fellow Ritabrata Bhattacharya, describe their progress in testing the holographic principle, which they say is a key property of any valid theory of quantum gravity. The team recently published their findings in the American Physical Society’s Physical Review Letters. Their research is supported by the National Science Foundation Elementary Particle Physics-Theory program.
“Proposed theories of quantum gravity are difficult to test experimentally because we don’t have the technology to predict effects occurring at extremely high energies or extremely small scales,” Varela says. “For theoretical physicists like us, a precise mathematical model is akin to the apparatus of an experimental physicist: It can be used to make predictions about the physical world.”
Pushing the Boundaries of Physics
For the USU team, the holographic principle is the vehicle to push forward toward a new frontier in physics thought.
“The holographic principle is our model to make predictions about quantum gravity,” Varela says.
Reference: “Class Superconformal Indices from Maximal Supergravity” by Ritabrata Bhattacharya, Abhay Katyal and Oscar Varela, 6 May 2025, Physical Review Letters.
DOI: 10.1103/PhysRevLett.134.181601
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