There is standard potted story about Albert Einstein and Quantum Theory. It goes something like this. Einstein is famous for his theory of relativity, but he had a lot to do with the discovery of quantum theory and in fact he actually won his Nobel Prize in 1921 for his photoelectric theory of 1905. However, as the theory developed he abandoned his work in it and came to oppose the theory, which was summed up in his quote “God does not play dice”. The quote is one of his most famous.

However, this oversimplified story fails to realistically reflect Einstein’s view on the theory and this standard bland representation fails to recognize his contribution to the Quantum revolution.

Why is it important?

For me it helps us to appreciate how important Einstein is and how he fundamentally influences the world in which we live because Quantum theory underpins our modern technology. As Margaret Wertheim says in Pythagoras’ Trousers “*No theory in the history of science has been more empirically successful than quantum mechanics. On the strength of quantum mechanics, humanity has built the microchip industry, and hence the computer industry. An understanding of the quantum realm has also given us the laser, and hence fiber-optic communications. CD players, bar code readers, laser surgery, laser guided weapons, and in the future probably also optical computing.”*

Einstein’s contribution to quantum theory is discussed in a new book ‘Einstein and the Quantum’, by A. Douglas Stone. In a wonderful summary of the creation of the theory he sets out how Einstein made the fundamental contributions to the conceptual pillars of Quantum theory. Those contributions were:

- Quantization of energy
- Force carrying particles (photons)
- Wave-particle duality
- Intrinsic randomness in physical processes and stimulated transitions (the basis of the laser)
- Indistinguishability of quantum particles
- Wave fields as probability densities

What stands out in the book is the breadth and depth of Einstein’s contributions to the Quantum theory and though it is contributions to our modern world, which is to a great degree built on the success of the theory.

In contrast to the simplified story at the beginning of the article, where Einstein is painted as the opponent of the theory, in truth his contribution to Quantum theory was deep, rich and fundamental. He did oppose its intrinsic randomness, but that crude tale should not be allowed to detract from what he achieved in the field.