martes, 13 de octubre de 2015

El transistor (bardeen y los colaboradores en el premio nobel)

El transistor (bardeen y los colaboradores en el premio nobel)
En el centro de todo esta el electron.
Most interested people understand much of what electrons do. But very few have any clear idea of what an electron actually is, or its implications for the concept of matter and its overthrow in the world economy.
From the telephone to the human brain, from the television set to the computer, information mostly flows in the form of electrons. This function of electrons has quantum roots. As in Planck’s black body radiation, electrons do not respond to applied energy in a continuous, proportional, or linear way. They are non-linear; they have quantum thresholds and resonances. These quantum functions shape their electrical properties. In order to move through a solid, electrons must be freed from their atoms, jumping from one energy state to a free state across measurable energy “band gaps” in strict accordance with quantum rules. These rules give electrons identifiable and controllable features that can be used to convey information.
With controlled pulses of electrons down wires, computers could be interconnected around the world. With controlled flows of electrons in and out of tiny capacitors, computer memories could be constantly read, written, and restored.
Crossing decisively into the microcosm, Heisenberg declared that the waves which Bohr had examined in recreating the atom were not conventional waves at all. Designated “probability amplitudes,” they were waves or fields that defined the statistical likelihood of finding an electron at any particular location. This was a climactic step in the overthrow of materialism in physics. With the electron itself depicted as a wave and the wave depicted as a probability field, the specific particle in this theory had disappeared into a cloud. With it disappeared the last shreds of Newtonian logic and mechanistic solidity.
As Bohr put it, quantum theory required “a final renunciation of the classical idea of causality and a radical revision of our attitude toward the problem of physical reality.”
Microcosm The Quantum Revolution In Economics And Technology .  Pagina 25
Los encargados de aplicar en forma práctica la teoría cuántica, fueron los inventores del transistor en 1948, lo cual significó un hito en la historia del desarrollo de las tecnologias de información.
John Bardeen (1908-1991), William B. Shockley (1910-1989), and Walter H. Brattain (1902-1987)
Bardeen en su Nobel Lecture de 1947 establece que en la raiz de toda la investigacion que condujo al desarrollo del primer transistor estuvo la Wilson’s quantum mechanical theory, based on the energy band model, and describing conduction in terms of excess electrons and holes. It is fundamental to all subsequent developments. The theory shows how the concentration of carriers depends on the temperature and on impurities.

JO H N BA R D E E N Semiconductor research leading to the point contact transistor
Nobel Lecture, December 11, 1956

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