• Aalto University physicists have developed a new quantum theory of gravity that is compatible with the Standard Model of particle physics.
• The theory treats gravity as a gauge force, similar to electromagnetism and the strong and weak nuclear forces, potentially unifying all four fundamental forces.
• This new approach could provide insights into high-energy phenomena like black holes and the Big Bang, where current physical models break down.

Physicists have long sought a 'Theory of Everything' that unifies all fundamental forces of nature. A significant hurdle has been reconciling general relativity, which describes gravity, with quantum field theory, which governs the other three forces. Mikko Partanen and Jukka Tulkki at Aalto University have proposed a new quantum theory of gravity that integrates gravity into the gauge theory framework used by the Standard Model. This approach, published in Reports on Progress in Physics, may pave the way for a more complete understanding of the universe's most extreme environments.

• What: A new quantum theory of gravity that describes gravity in a way compatible with the Standard Model of particle physics using gauge theory and renormalization techniques.
• Who: Mikko Partanen and Jukka Tulkki at Aalto University in Finland.
• When: The research was published in May 2025 in the journal Reports on Progress in Physics.
• Where: Aalto University, Finland, with implications for understanding the universe at large, particularly black holes and the Big Bang.

The new quantum gravity theory represents a significant step toward unifying our understanding of the fundamental forces. By framing gravity within the gauge theory of the Standard Model, the researchers address the long-standing incompatibility between general relativity and quantum mechanics. This approach offers potential insights into extreme cosmic phenomena and might eventually lead to a 'Theory of Everything'. However, further research is needed to validate the theory's consistency and explore its full implications. The invitation to the wider scientific community to scrutinize and build upon the work is crucial for advancing this promising avenue of inquiry.

If this turns out to lead to a complete quantum field theory of gravity, then eventually it will give answers to the very difficult problems of understanding singularities in black holes and the Big Bang.

The most familiar gauge field is the electromagnetic field. When electrically charged particles interact with each other, they interact through the electromagnetic field, which is the pertinent gauge field. So when we have particles which have energy, the interactions they have just because they have energy would happen through the gravitational field.

A theory that coherently describes all fundamental forces of nature is often called the Theory of Everything. Some fundamental questions of physics still remain unanswered. For example, the present theories do not yet explain why there is more matter than antimatter in the observable Universe.

If renormalization doesn’t work for higher order terms, you’ll get infinite results. So it’s vital to show that this renormalization continues to work.

The proposed quantum gravity theory offers a promising framework for unifying gravity with the other fundamental forces. While the theory requires further validation and refinement, its compatibility with the Standard Model and its potential to address longstanding puzzles in physics make it a significant development. Ongoing research and collaboration within the scientific community will be crucial in determining the ultimate success and impact of this theory.