Quantum Mechanics in history

Quantum Mechanics is a fundamental branch of physics with wide applications. The foundations of quantum mechanics were established during the first half of the twentieth century by Werner Heisenberg, Max Planck, Louis de Broglie, Albert Einstein, Niels Bohr, Erwin Schrödinger, Max Born, John von Neumann, Paul Dirac, Wolfgang Pauli and others.

The history of quantum mechanics began essentially with the 1838 discovery of cathode rays by Michael Faraday, the 1859 statement of the black body radiation problem by Gustav Kirchhoff, the 1877 suggestion by Ludwig Boltzmann that the energy states of a physical system could be discrete, and the 1900 quantum hypothesis by Max Planck that any energy is radiated and absorbed in quantities.

On 19 October 1900 the Berliner Max Planck at age 42 announced a formula that fit the experimental result perfectly, yet he had no explanation for the formula – it just happened to fit.

He worked to find an explanations through the late fall and finally was able to derive his formula by assuming that the atomic jigglers could not take in any possible energy, but only certain special ‘allowed’ values. He announced the result ion 14 December 1900 and this date is now considered the birthday of quantum mechanics.

According to the theorem proved by Gustav Kirchhoff in 1859 on the basis of the second principle of thermodynamics, the blackbody spectrum has a very remarkable property: It is a universal function of temperature only. In the 1877, Ludwig Boltzmann and Willy Wien restricted the form of this function by combining electromagnetism and thermodynamics.

In 1905, Einstein computed the entropy of dilute thermal radiation from the high frequency limit of Planck’s law.

In 1913, Niels Bohr emphasized that mathematical symbols from classical mechanics permitted visualization of the atom as a minuscule Copernican system. Although suitably quantized laws of classical mechanics are used to calculate the electron’s allowed orbits, or stationary states, classical mechanics can neither depict nor describe the electron in transit.

Arnold Sommerfeld and others extended the Bohr model with considerable but incomplete success. In1925, the first form of quantum mechanics, was invented by 23 year-old Heisenberg, which soon became known as ‘matrix mechanics’. Heisenberg focused attention on an ‘observable’ set of quantum amplitudes, each depending on not one but two stationary phase.

In 1932 von Neumann put quantum theory on a firm theoretical basis. Some of the earlier work had lacked mathematical rigour, but von Neumann put the whole theory into the setting of operator algebra.

In 1933 Fermi develops a successful quantum field theory of beta decay. It describes how neutrons spontaneously change into protons and emit electrons and neutrinos.
Quantum Mechanics in history

Who was Charles Darwin (1809-1882)?

Charles Darwin took five years trip around the world on a ship called the Beagle, but he liked staying home best of all.

Charles Robert Darwin was born on February 12, 1809, in Shrewsbury, a small village in England. He was the second son and fifth of six children of Dr. Robert Darwin, an eminently successful physician, who in turn was the son of Erasmus Darwin, the author of Zoonomia.

He studied at Edinburgh and received his BA from Cambridge in April 1831.  Charles Darwin is among the most influential scientists who ever lived.

Darwin’s observations in the Galapagos and in the other countries he visited had a profound effect on his thinking. Darwin began to think about the relationships among the facts he was accumulating.

In July 1837, less than none months after landing at Falmouth, Darwin began writing downs his thoughts on their relationship and origins of species in a notebook.

He changed the way humans view their place in nature. His explanation of the evolutionary process occurring through natural selection forms the basis of modern-day biological sciences, including the applied disciplines of agriculture, medicine and most recently biotechnology.
Who was Charles Darwin (1809-1882)?