Vacuum Fluctuations
The vacuum state or is the state of lowest energy and the expectation values of and vanish in this state:
The electrical and magnetic fields and the vector potential have the mode expansion of the same general form:
Thus it is easy to see that the expectation values of these field operators vanishes in the vacuum state:
However, it can be shown that the expectation values of the square of these field operators is non-zero. Thus there are fluctuations in the field about the zero ensemble average. These vacuum fluctuations are responsible for many interesting phenomenon including the Lamb shift in quantum optics.
Read more about this topic: Fock State
Famous quotes containing the word vacuum:
“No, it wasn’t an accident, I didn’t say that. It was carefully planned, down to the tiniest mechanical and emotional detail. But it was a mistake. It was a beaut. In the end, somehow granted the time for examination, we shall find that our so-called civilization was gloriously destroyed by a handful of vacuum tubes and transistors. Probably faulty.”
—John Paxton (1911–1985)