Science makes progress in weird ways. Our understanding of how baseballs arc and moons orbit requires calculus to fully understand. An entire field of math had to be developed to make the same calculations our brains do automagically every time we go to catch something. Understanding quantum mechanics required Dirac to invent yet more maths, and with relativity, field theories entered regions they had never entered before.

When researchers try to understand complex problems there is almost always this underlying fear or excitement – or both – that new math is going to be required. As Daniel Persson puts it: We strive to understand the laws of nature, and the language in which these are written is mathematics. When we seek answers to questions in physics, we are often led to new discoveries in mathematics too. This interaction is particularly prominent in the search for quantum gravity – where it is extremely difficult to perform experiments.

Quantum gravity is that just-out-of-research concept that unifies quantum mechanics and gravitation, with all its relativistic twists and turns. Robert Berman explains: The challenge is to describe how gravity arises as an ‘emergent’ phenomenon. Just as everyday phenomena – such as the flow of a liquid – emerge from the chaotic movements of individual droplets, we want to describe how gravity emerges from the quantum mechanical system at the microscopic level.

And Berman and his colleagues just might have succeeded. Maybe. Or as Berman puts it: Using techniques from the mathematics that I have researched before, we managed to formulate an explanation for how gravity emerges by the holographic principle, in a more precise way than has previously been done.

The holographic principle is part of string theory that explains that any higher dimension volume can be described on a lower dimension surface. As Larry Susskind explains: The three-dimensional world of ordinary experience––the universe filled with galaxies, stars, planets, houses, boulders, and people––is a hologram, an image of reality cited on a distant two-dimensional (2D) surface.

Basically, according to the holographic principle, all of reality really is just shadows on a wall as Plato suspected.

If this math proves to not only match reality but also to have testable predictive qualities, then this team is destined to win a Nobel Prize, but experiments will be needed. This is a “watch this space” kind of result. String theory has never been proven. It is a lot of really ugly math that can be tuned to match what we see, but it hasn’t made unique predictions that make it clear it is more than just math, like Ptolemy’s epicycles, that seems to work if you fuss hard enough with it.

So watch this space. Maybe gravity and quantum mechanics can be unified or maybe not. Time and testable predictions will tell.

More Information

Chalmers University of Technology press release

“Emergent Sasaki-Einstein geometry and AdS/CFT,” Robert J. Berman, Tristan C. Collins, and Daniel Persson, 2022 January 18, Nature Communications