Lecture 3 – The quantum leap

From the 1999 lecture programme:

What is the shortest time-scale that can be measured, and is there any in-built uncertainty which will ultimately limit the accuracy of such a measurement?

Such issues force us to look into the ultrasmall world of atoms, and the seemingly magical properties of "quantum mechanics". Indeed it is from these microscopic building blocks that the world's most accurate clocks are now being made.

Two hundred years ago Michael Faraday, who started the Royal Institution Christmas Lectures, was gaining a reputation as the father of electricity. However he was unaware of the microscopic origins of the effects he observed. In fact it was not until one hundred years later that the extraordinary quantum world of electrons and atoms was revealed. In the quantum world, particles are waves, and waves are particles this statement sounds simple, but its consequences are quite revolutionary and are still being debated.

It is the wavelike behaviour of the electrons in semiconductors that ultimately allow us to use semiconductors to create our modern high-tech world based on silicon chips. As a result, we have been able to develop ultra-fast digital communications, desktop computers, mobile phones and CD players. As our increasingly rapid lifestyle demands even faster computers and electronic devices, manufacturers are striving to design ever smaller silicon chips.

However we will soon reach the physical limits of standard chip design. We will then be faced with the daunting prospect of having to harness the stranger properties of quantum mechanics in order to achieve faster information processing.

However instead of halting progress, the quantum world offers us the exciting possibility of exploiting some quite miraculous effects. It is ironic that it is some of these stranger properties of quantum mechanics which Einstein never liked despite the fact that he was awarded the Nobel Prize for his contribution to quantum mechanics!


BBC / Royal Institution




Neil Johnson



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