Henning Genz Quotes

This question about the reason we do not observe any quantum mechanical uncertainty in the appearance of flies or stars was never tackled by the inventors of quantum mechanics. Given that we are convinced that the basic laws of quantum mechanics are at the bottom of all mechanical laws, and that the beginning of our world can be understood exclusively in quantum mechanical terms, we have to ask ourselves: Why are there any observable systems at all on the classical side of the demarcation line between classical mechanics and quantum mechanics? Why are there these stumbling blocks, these flies, these stars? The demarcation line proper, between quantum physics and classical physics, was clearly stated by the fathers of quantum mechanics: Classical laws govern large and heavy classical systems. But they failed to tell us how and why the world became that way.

LIGHT AS AN EXCITATION OF SPACE

Let's try and understand light in terms of an excitation of empty space-even if that makes no immediate sense. We might alternatively understand light in terms of a field, as we introduced that term in chapter 2. But light differs from the fields of temperature distributions, of sound, or of water in fluid motion described there: Whereas those phenomena are due to the composite action or motion of molecules at a more elementary level, light has its own reality at that level. It cannot be understood in terms of an oscillation of some matter that also exists in the dark-no, light is nothing but just that, light. It is an oscillation of an abstract nature, equivalent to a set of numbers that are assigned to each point in space. True, these abstract numbers have implications-most notably, they imply energy. But while a water wave transports energy by the movement of water molecules, the passing of a light wave does not mean that anything material oscillates. The energy of the liquid wave is the energy associated with gravitation and motion of its molecules; the energy of light is energy pure and simple, associated with every illuminated point in space.

Any space that distinguishes directions and accelerations cannot be "empty", in Aristotle's meaning.

The universe is but one immense unit; it cannot be separated into spatial domains that are totally empty and others that are completely filled with matter. Matter and space can be distinguished from each other, but where we draw the blurred line between them is largely a matter of taste.

To date we know only two real media that offer almost no resistance to moving bodies.
One such medium was discovered in the 1930s: If we cool down helium, a noble gas, to temperatures close to absolute zero, it will flow through the thinnest of tubes with almost no friction. This phenomenon is called superfluidity. Another substance that shows superfluidity is a rare isotope of the same element, called helium-3. It takes experience to explore all the facets nature offers us. No form of logic can replace it.