Tuesday, October 6, 2009

Energy And Information

Site of the day: http://openwetware.org/

The Dance of Particles and Bits

In the 20th and 21st centuries, computer science and physics have teamed up to explore the enigmatic relationship between energy and information.

Both energy and information are among the most difficult concepts to understand because they are so fundamental to the nature of the universe. Everything described in physics ultimately comes down to energy. For example, most people know of Einstein's famous equation, mass times the square of the speed of light equals energy. Matter is energy.

In fact, matter is a stored form of energy. Matter is a combination of energy and information. On a quantum level, all particles can be described by bits of information. How the information is mapped to energy is dependent on the observer. The observer need not be human either, it could be a neighboring particle.

In recent decades several new theories have developed in parallel with the rise of computer science, such as emergence, and complexity theory. The most revolutionary of these is the idea that the universe, and all matter in it, are self-computing. In a closed system of two particles (they could be anything), the particles can interact through the four fundamental forces. How they interact depends on what kind of particles they are the forces that are available to them. Information and energy can be exchanged, and the two particles will quickly come to a state of equilibrium. Since particles follow a different set of rules than macroscopic objects like billiard balls, this equilibrium isn't a state of rest, but rather a pattern.

This is illustrated to great effect with cellular automata, a simplified two-dimensional analog of particle systems. In a system of cellular automata, also known as the "Game of Life", there is a grid of cells. Each cell can be on or off, and the cells in the grid are given a set of rules to follow. For instance, if a cell is on, and three of it's neighboring cells are on, it must turn off. If a cell is off, and three of its neighbors are off, it must turn on. Information is exchanged between that cell and it's neighbors. Since all of the cells are constantly calculating how other cells are affecting them, the system will change rapidly, but it will usually settle into an oscillating pattern.

The same is true for systems of particles, though it is complicated by quantum uncertainty, and probabilities are important. Large systems of particles are best analyzed with statistics, though at the macroscopic scale the weirdness of quantum mechanics evens out and information systems are more predictable.

by Katharine M. J. Osborne (http://physics.suite101.com/article.cfm/energy_and_information)

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