“A theory that coherently describes all fundamental forces of nature is often called the Theory of Everything,” Aalto University postdoctoral researcher Mikko Partanen said. It has been the physicists’ holy grail, a thorn in the side of earlier researchers. The thrilling prospect of a union of gravity with the nuclear strong and weak forces and electromagnetism has pushed physicists to expand the reach of Einstein’s general theory of gravity and quantum field theory.
The tension between these two pillars of physics in the twentieth century has been an annoying problem. Quantum field theory is a probability-based theory of interactions among infinitesimally small particles and general relativity is a deterministic theory of large-scale geometry of the universe. Both have each been a success, but the two theories cannot be added. Partanen and co-author Jukka Tulkki have devised this solution with the solution of building a new theory of gravity based on the Standard Model of particle physics. The innovation would give a clearer picture of how the universe came into being, i.e., black holes and the Big Bang.
The key to their solution lies in the key to gauge theory. “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,” Tulkki states. Fields intervene between particles here, and gravity as a gauge field such as the electromagnetic field is treated. The problem has been to build a gauge theory of gravity that is compatible with the other three forces. The Standard Model is a gauge theory that explains these forces with some symmetries. Partanen and Tulkki’s paper tries to apply these symmetries to gravity, hoping for a quantum mechanics-general relativity unification.
They have good but not decisive results. Renormalization, a mathematical method to handle the infinities that arise in mathematics, is used by the theory. While they have shown that it works for first-order terms, they require more evidence for it to work for all orders. “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,” Tulkki warns. Despite issues, the scientists are hopeful to overcome them through diligence and time.
Partanen and Tulkki challenged scientists to apply their theory, experiment with its outcome, and improve it. “Like quantum mechanics and the theory of relativity before it, we hope our theory will open countless avenues for scientists to explore,” Partanen explains. Their study comes a long way in solving the renowned conflict between general relativity and quantum mechanics.
For researchers who would like to explore the intricacies of the force of gravity and unification principles, the future of the work is vast. The potential to bring about a new age of scientific knowledge, as gravity has done with technologies like GPS, is within their grasp. As Partanen and Tulkki proceed with their work, the world of science holds its breath for the breakthroughs in the works.
The quest for the everything theory continues, but the effort by Partanen and Tulkki is a harbinger of things to come. Not only does it render our knowledge of gravity even more intriguing, but it also challenges us more to collaborate and innovate towards a single explanation of all the basic forces. The quest for a marriage of general relativity and quantum mechanics continues, and scientists hold their breaths while new areas of research await them.
