The Power of Symmetry

Symmetry is everywhere. We find it in art, music and architecture – and in biology, chemistry and physics. Many objects in the world around us are symmetrical, and we associate such symmetry with beauty, order and simplicity. In modern physics, however, we are not only interested in the symmetry of objects, but also with the symmetries of the physical laws themselves. In my lecture, I will explain how these laws, at the most fundamental level, are governed by symmetries.

We will start by describing the hidden spacetime symmetry of Maxwell’s theory of electromagnetism, which famously led Einstein to develop his theory of relativity. We will explain that such symmetries are not consequences of the laws of dynamics, but are rather the core principles that define these laws. It is through this profound change of perspective that symmetries have been put at the heart of fundamental physics. 

Next, we will discuss the internal symmetries of quantum fields, which underly the structure of the Standard Model of particle physics. We will describe how symmetry explains the difference between matter and forces, how the stability of matter follows from symmetries and how the nature of the fundamental forces is dictated by symmetries. We will also show how the Higgs field breaks the symmetry between the electromagnetic and weak nuclear forces and gives a mass to all elementary particles. Finally, we will explore how symmetries and symmetry breaking manifest themselves on a cosmic scale, by describing how symmetries shape the structure and evolution of our Universe.