Introduction To Quantum Mechanics - Development of Modern Quantum Mechanics

Development of Modern Quantum Mechanics

In 1925, building on de Broglie's hypothesis, Erwin Schrödinger developed the equation that describes the behaviour of a quantum mechanical wave. The equation, called the Schrödinger equation after its creator, is central to quantum mechanics, defines the permitted stationary states of a quantum system, and describes how the quantum state of a physical system changes in time. In the paper that introduced Schrödinger's cat, he says that the psi-function featured in his equation provides the "means for predicting probability of measurement results," and that it therefore provides "future expectation, somewhat as laid down in a catalog."

Schrödinger was able to calculate the energy levels of hydrogen by treating a hydrogen atom's electron as a classical wave, moving in a well of electrical potential created by the proton. This calculation accurately reproduced the energy levels of the Bohr model.

At a somewhat earlier time, Werner Heisenberg was trying to find an explanation for the intensities of the different lines in the hydrogen emission spectrum. By means of a series of mathematical analogies, Heisenberg wrote out the quantum mechanical analogue for the classical computation of intensities. Shortly afterwards, Heisenberg's colleague Max Born realised that Heisenberg's method of calculating the probabilities for transitions between the different energy levels could best be expressed by using the mathematical concept of matrices.

In May 1926, Schrödinger proved that Heisenberg's matrix mechanics and his own wave mechanics made the same predictions about the properties and behaviour of the electron; mathematically, the two theories were identical. Yet the two men disagreed on the interpretation of their mutual theory. For instance, Heisenberg saw no problem in the theoretical prediction of instantaneous transitions of electrons between orbits in an atom, but Schrödinger hoped that a theory based on continuous wave-like properties could avoid what he called (in the words of Wilhelm Wien) "this nonsense about quantum jumps."

Read more about this topic:  Introduction To Quantum Mechanics

Famous quotes containing the words development of, development, modern, quantum and/or mechanics:

    They [women] can use their abilities to support each other, even as they develop more effective and appropriate ways of dealing with power.... Women do not need to diminish other women ... [they] need the power to advance their own development, but they do not “need” the power to limit the development of others.
    Jean Baker Miller (20th century)

    John B. Watson, the most influential child-rearing expert [of the 1920s], warned that doting mothers could retard the development of children,... Demonstrations of affection were therefore limited. “If you must, kiss them once on the forehead when they say goodnight. Shake hands with them in the morning.”
    Sylvia Ann Hewitt (20th century)

    How little do the most wonderful inventions of modern times detain us. They insult nature. Every machine, or particular application, seems a slight outrage against universal laws.
    Henry David Thoreau (1817–1862)

    A personality is an indefinite quantum of traits which is subject to constant flux, change, and growth from the birth of the individual in the world to his death. A character, on the other hand, is a fixed and definite quantum of traits which, though it may be interpreted with slight differences from age to age and actor to actor, is nevertheless in its essentials forever fixed.
    Hubert C. Heffner (1901–1985)

    the moderate Aristotelian city
    Of darning and the Eight-Fifteen, where Euclid’s geometry
    And Newton’s mechanics would account for our experience,
    And the kitchen table exists because I scrub it.
    —W.H. (Wystan Hugh)