Angel "Java" Lopez en Blog

Publicado el 20 de Noviembre, 2016, 14:13

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¿Por qué encuentra energía negativa? Porque al pasar a relatividad, la expresión del operador energía se ve transformado por una raíz cuadrada, que en mecánica cuántica se traduce en que los dos valores son posible. Es algo técnico para discutirlo ahora en detalle, pero el resultado es que la solución de Dirac hace aparece no SOLO un spinor sino DOS spinores. Y el tema de las energías negativas da para la aparición de uno de los temas más interesantes del siglo pasado: el descubrimiento de las antipartículas.

As frequently happens with the mathematical procedure in research, the solving of one difficulty leads to another. You may think that no real progress is then made, but this is not so, because the second difficulty is more remote than the first. It may be that the second difficulty was really there all the time, and was only brought into prominence by the removal of the first.

This was the case with the negative energy difficulty. All relativistic theories give symmetry between positive and negative energies, but previously this difficulty had been overshadowed by more crude imperfections in the theory.

The difficulty is removed by the assumption that in the vacuum all the negative energy states are filled. One is then led to a theory of positrons together with electrons. Our knowledge is thereby advanced one stage, but again a new difficulty appears, this time connected with the interaction between an electron and the electromagnetic field.

Eso de tener todos los estados negativos llenos solo sirve cuando manipulamos fermiones, partículas que obedecen al principio de exclusión de Pauli.

When one writes down the equations that one believes should describe this interaction accurately and tries to solve them, one gets divergent integrals for quantities that ought to be finite. Again this difficulty was really present all the time, lying dormant in the theory, and only now becoming the dominant one.

Esta divergencia es la que realmente preocupa a Dirac, como veremos en los próximos posts.

Nos leemos!

Angel "Java" Lopez
http://www.ajlopez.com
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Por ajlopez, en: Ciencia