Why Quantum Physics

Why Quantum Physics

How does the universe work? What are the principles that underlie natural phenomena? Philosophers have pondered such questions for millennia; their answers reflect the world view of Western civilization-how we perceive ourselves in relation to the universe. In the early years of this century the dominant world view was determinism, a tenet that had its origins in the philosophical musings of Descartes. Descartes' metaphor for the universe was a gigantic clockwork machine, a Rube Goldberg device that grinds relentlessly onward, towards eternity. According to this interpretation, the future is preordained and fully predictable. All of existence is described precisely by physical laws, and, in principle, can be known by man. Nature, however, had a surprise in store for philosophers. In the first decades of the twentieth century, they were to see this world view subverted, uprooted, and toppled by a young upstart physical theory called quantum mechanics. Theoretical physics has come a long way since those fateful days in the 1920's and 30's when physicists were taking the first tentative steps towards a radical new definition of reality. So far have we come that in 1981 the physicist Steven Hawking could reasonably predict that

... by the end of the century. ... we might have a complete, consistent, and unified theory of the physical interactions which would describe all possible observations.

The foundation of that unified theory is quantum mechanics, the subject matter of this book. What is quantum mechanics? You probably know that if you want to understand how a transistor works or the principles behind the laser in your compact disc player you'd better not use classical physics. Newton 's mechanics and Maxwell's electromagnetic theory can explain macroscopic phenomena, such as the motion of billiard balls or rockets, but fail spectacularly when applied to microscopic phenomena, such as proton-atom scattering or the flow of electrons in a semiconductor. An understanding of such processes requires a better mousetrap: quantum mechanics. More precisely, quantum mechanics is a collection of postulates based on a huge number of experimental observations, and the tools derived from those postulates. We use these tools to analyze, predict, and understand microscopic phenomena. Hence quantum theory forms the bedrock of the modem physics of matter-atoms, molecules and solids-and is at the core of such diverse sciences as astrophysics and biochemistry. In its more pragmatic guises, quantum mechanics plays a vital role in a vast array of technological applications, some of which we use every day-e.g., the microchips in the computers.

The source:

Michael A. Morrison - Understanding Quantum Physics.

By. Fady Tarek