Quantum Mechanics

Dirac wrote the following about quantum mechanics: “The underlying physical laws necessary for the mathematical theory of a large part of physics and the whole of chemistry are thus completely known, and the difficulty is only that the exact application of these laws leads to equations much too complicated to be soluble. It therefore becomes desirable that approximate practical methods of applying quantum mechanics should be developed, which can lead to an explanation of the main features of complex atomic systems without too much computation.” In this talk I shall discuss the emergence of quantum mechanics, explain why the equations are too complicated to solve and introduce the practical methods that have been developed which now allow predictive quantum mechanical modelling of much of physics, chemistry, materials science and biology.