Download PDF The Physics of Quantum Mechanics by JAMES BINNEY

Sinopsis

In the middle of the twentieth century geopolitics was profoundly changed by the development of nuclear weapons. Since then, the existence of these devices of appalling destructive power has attenuated conflicts between nuclear-armed states, and efforts to limit access to these weapons have been central to international relations. In the 1960s and 70s a significant fraction of the world’s electricity supply began to be generated by nuclear reactors. The physics of an atomic nucleus can only be understood with quantum mechanics, and the founders of quantum mechanics played major roles in the unleashing of nuclear power.

At the end of the twentieth century digital devices began to become commonplace. By 2012 a mobile phone was to be found in roughly half the planet’s dwellings, and every significant business relied on computers for record keeping and, increasingly, for sales. Digital cameras had almost entirely displaced photographic film and in developed countries children and adults were spending significant fractions of their lives interacting with hand-held electronic devices such as smartphones. In the last decade of the twentieth century television cameras became digital, and in the first decade of the twenty-first century broadcasting became increasingly digital, which made it possible to increase the number of channels available to viewers by more than a factor of 10. Major social and political changes seemed to arise from satellite television and social media carried by smartphones and other digital devices. These devices are made possible by quantum mechanics – not only is there a direct connection, physically, between the quantum sobriquet and the digital nature of the devices, but the quantum theory of crystalline matter plays a fundamental role in the design of the silicon chips and ferromagnetic discs that drive digital devices.

If you fall sick and go to hospital you are likely to be put in an MRI machine, which uses the quantum theory of spin, and your treatment may have benefited from the ability of electron microscopy to let us see viruses, so you will benefit from the quantum theory of electron scattering. Your diagnosis may involve positron-annihilation tomography, which uses particles whose very existence was predicted by the quantum theory of

fields. Whatever drugs you take are likely to owe much to the ability of quantum mechanics to explain the nature of chemical bonds.

Quantum mechanics emerged in the first three decades of the twentieth century, was elaborated in the next two decades, and has since become important in one aspect after another of human existence. Our civilisation is already hugely dependent on quantum mechanics and this dependence seems set to grow for the foreseeable future. Yet only a tiny minority of mankind has any significant knowledge of this key discipline.

The study of quantum mechanics not only confers power – the power to predict what will happen in a possible physical situation and thus the ability to design new devices – but it also opens new intellectual horizons. It is founded on a concept, probability amplitude, that violates conventional logic and is unique to quantum mechanics. It has also given enough insight into the bowels of Nature to grasp that physical reality, whatever it is, is completely different from the world we see, hear and touch. By enabling us to understand how stars work, quantum mechanics has laid the cosmos open, like a book ready for reading, and by giving

birth to the theory of inflation has offered a picture of the origin of the universe. It seems probable that in the years to come quantum mechanics will deliver further revolutionary insights into the material world.

Content 

1. Introduction
2. Operators, measurement and time evolution
3. Oscillators
4. Transformations and observables
5. Motion in step potentials
6. Composite systems
7. Angular momentum
8. Hydrogen
9. Motion in a magnetic field
10. Perturbation theory
11. Helium and the periodic table
12. Adiabatic principle
13. Scattering theory

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