Gravity and entropy—two fundamental concepts in physics—might be more closely connected than we thought. A new theory proposes that gravity could emerge from entropy, challenging the traditional understanding of how forces shape the universe. If this holds up, it could bridge the long-standing gap between general relativity and quantum mechanics, bringing physics closer to a unified framework.
Physicist and mathematician Ginestra Bianconi from Queen Mary University of London explores this idea by treating spacetime as a quantum operator, meaning it acts on quantum states to transform them. Quantum relative entropy, which measures disorder or unpredictability, may dictate how gravity functions at the quantum level. This approach attempts to reconcile Einstein’s general relativity—where gravity is the curvature of spacetime—with quantum mechanics, which describes reality at subatomic scales.
General relativity explains gravity as the warping of spacetime caused by mass. A massive object like the Sun bends spacetime, pulling planets into orbit. Quantum mechanics, in contrast, describes the universe in terms of fundamental particles that exist in both particle and wave states. The challenge has been to develop a model that unites these two perspectives.
Bianconi’s theory modifies general relativity by introducing quantum entropy into the equation. This allows spacetime to be described with a low-energy curvature while also predicting a small cosmological constant, a key factor in understanding the expansion of the universe. The framework also incorporates a gravitational field, or G-field, which functions as a Lagrangian multiplier—used to determine the maximum and minimum of a function. This mathematical approach could help describe how quantum waves interact with spacetime, offering a possible path to quantum gravity.
If gravity has a quantum nature, it could exist in both particle and wave forms. This raises intriguing questions about dark matter. The mysterious substance, which makes up about 27% of the universe’s mass-energy content, has never been directly detected, but it behaves like a form of invisible matter influencing galactic motion. Bianconi suggests that the G-field, if confirmed, might provide insight into the nature of dark matter.
While this idea remains theoretical, it presents a fresh angle on one of physics’ biggest puzzles. If entropy plays a role in gravity’s emergence, the very nature of spacetime and matter could be fundamentally different from what we currently assume. More research is needed to determine whether this approach can stand up to experimental scrutiny, but it adds another piece to the ongoing quest for a unified theory of physics.