Smaller than an atom, smaller than a quark, smaller even than a neutrino, the single bit may be the most fundamental building block. Without any strucutre the bit is just there, or not there. John Wheeler believed that all material objects are composed of bits of information, and he expressed the idea with this slogan: It from Bit.
Recent trend in physics has been to formulate physical laws in terms of information. This approach has many advantages specially in understanding the causal relationships in Quantum Mechanics and Quantum Entanglement. I pointed out that Quantum Mechanics can be reformulated from basic principles of information conservation in my paper. Recently General Relativity has been formulated as entropy + information. This approach has its advantages. But what the heck is information ?
In the sense that physicists use the word information is made up of matter(not just made up of atoms but other subatomic particles as well) and is stored somewhere in spacetime. John Wheeler imagined that the bit , being the basic of all objects is equal to the smallest possible in size- that fundamental quantum of distance discovered by Max Plank. Space can be divided into plank sized cells similar to a 3-D checkboard. A bit can be pictured as a very simple particle, which may occupy the cell or not. The Physical conditions can be thought of as the configuration of such a large checkboard.
In this Wheeler, world of information, the laws of physics would consist of rules for how the configuration of bits is updated from instant to instant. Clearly this is a powerful approach. I plan to write a series of such articles discussing quantum theory and GR. But first lets talk about information conservation :
Consider the system on the left. In such a system the past and the future are uniquely determined. In a sense we never lose the information as to where we are and where we came from. This is the simplest manifestation of conservation of Information.
Conservation of Information is the most fundamental principle of physics. It is the cornerstone of all of physics. Stephen Hawking suggested that this principle was violated by Black Holes. Thats the topic of my next post.
Incidentally, is information conserved in Quantum Mechanics ? Tell me what you think.