## Understanding Quantum

^{th}July 2019

Book through the Sydney Observatory website or phone 9217 0111.

Classical physics provided us with an intuitive description of the world about us. It introduced concepts of force, energy and momentum which combined are powerful tools to predict the dynamics of many physical system. With the coming of the twentieth century the limits of this physics were starting to be found. The limits became apparent with the discovery of the very small build block of the universe. A new physics was required for the new fundamental particles of nature.

This new physics drew on classical physics but it required very new abstract concepts to provide accurate predictive powers for the atomic realm. The first lecture will introduce you to the classical concepts that still play a role in quantum physics, and how they have been reinterpreted.

All the fundamental building blocks possess both a wave and particle nature. The wave is used to predict where a particle may be and the momenta the particle may possess. Neither can be known with absolute certainty. In this lecture we encounter the Uncertainty Principle. A principle at the very heart of Quantum Physics that encapsulates Quantum's conceptual deviation from classical physics.

We look at the intrinsic quantum nature of elementary particles. One quality called spin provides us with a simple property to model. Quantum mechanics provides a mathematical description of this quantum nature with very good predictive powers. The course does not contain any of the maths but provides you with a graphical model for the maths. We apply this model to the polarization of light.

When light is detected it reveals itself as a particle, called a photon. We apply our graphical model to common optical effects like: reflection, diffraction and refraction. The theory explains the rainbows seen in DVDs an the colours of some brilliant butterflies.

We explore the quantum model of the atom and the spectra they produce. We see how quantum explains many of the characteristics of the elements of the period table. We see how this is applied to astronomy

Entanglement is a property of some quantum systems. This spooky action at a distance is explained and the how it may lead to advanced computing in the future.