Announced on July 6, 2019, the Selection Committee of Special Breakthrough Prize in Fundamental Physic has picked three theoretical physicists, Sergio Ferrara (CERN), Daniel Z. Freedman (MIT and Stanford), and Peter van Nieuwenhuizen (Stony Brook University), as the this year's award recipients, to honor the framework of supergravity they developed in the 1970s.
Their work not only succeeded in unifying gravitational force with quantum mechanics based on mathematics, but also established a solid theoretical foundation for the ongoing attempts to define the geometry of space-time at a fundamental level.
The 20th century was a great era for physicists. In the early 1900s, Einstein rewrote our understanding of gravity by introducing the concept of the curvature of spacetime, as described in his elegant theory of special relativity.
Then came the 1960s and 1970s, when the physics community came up with the Standard Model, an elaborate, hypothetical system developed based a quantum field theory. It successfully accounted for three of the four known fundamental forces (the electromagnetic, weak, and strong interactions) and put a large variety of elementary particles in order. However, no one has any idea on how to fit gravity into this grant picture of the physical world.
1973 saw the birth of the “supersymmetry” principle, a scheme that was designed to pair up "force" and "matter". For example, it postulated that each of the known particles (the fermions) that make up matter has a partner which are force-carrying particles (the bosons).
Ferrara, Freedman and van Nieuwenhuizen took on the task to use the supersymmetry principle to describe the gravity so that this fundamental force won't be an outcast anymore. Enter supergravity.
The centerpiece of their theory, backed by a huge amount of computed-based modeling and calculations, postulates the existence of “gravitinos”, a fermion partner to the graviton, the boson that embodies gravitational force.
The framework of the supergravity has far-reaching implications and left an influential legacy. It established a stable mathematical groundwork for future theories to stand on.
For example, not long after its publication, physicists working on string theory, a candidate for the Theory of Everything, finally managed to incorporate gravity into their system. The key to their progress is the comparability between supergravity and string theory on how to describe low-energy interactions.
It will be curious to see how supergravity, the proof that quantum physics-based on supersymmetry can explain all the phenomena in our world, will continue to transform how we understand space and time.
Ferrara, Freedman, van Nieuwenhuizen Awarded 2019 Special Breakthrough Prize in Fundamental Physics (Breakthrough Prize)