2.2.9. Example of how Coherence Changes Properties of Matter

1. Summary: The text discusses the concept of coherence in relation to the properties of matter, using examples of graphite and diamonds, both made of carbon but with different structures due to varying degrees of coherence. It also mentions how polarized light microscopy reveals the organized crystal structure of minerals, with different colors indicating different coherent domains. The speaker emphasizes that the degree of coherence significantly alters the properties of matter.

Now, okay, so we approach the concept of coherence more from the analogy point of view, more of the feeling point of view, but is there any experimental evidence if there is any truth to it? Well, first of all, the fact that the degree of coherence profoundly changes properties of matter is very well known. What you're looking at is simply carbon, but in two states of coherence. On the right, you will see graphite. So there, all atoms of carbon are organized in a coherent manner, but only in a 2D coherence. It's just a sheet of layers of carbon. And here we have the one of the softest minerals is completely black. to know it's like in pencil. On the left, you see diamonds, also consisting of carbon. But diamond has 3D coherence. It's a very strong, very rigid structure. It is one of the most hardest minerals known to man and is almost completely transparent. So again, think about this. By chemically speaking, it's identical. It's just carbon. What has changed is the degree of coherence, the way our individual atoms are put together. The crystal structure is completely different. To give you another example, this crystalline structure is very well known, obviously, in minerals where this crystal structure is highly organized. So what we're looking at here is a mineral under a microscope. It uses a special kind of light called a polarized light microscope. So if we will rotate the mineral under the microscope, what we'll see different colors. This is because the angle of light coming into different domains changes, we'll see a different color. But what it means basically is that every color responds to a rigid crystal coherent domain. Again, very familiar, we all know about this or at least about diamond and graphite. It's completely acknowledged.