One can say that the career of Albert Einstein started in 1900, when he was granted a teaching diploma by ETH school in Zurich. Einstein there wrote his first published paper, titled "Consequences of the observations of capillarity phenomena”.

Upon graduation, Einstein could not find a higher education teaching post. The father of a classmate helped him obtain a job as a technical assistant examiner at the Swiss Patent Office in 1902. He obtained his doctorate after submitting his thesis "A new determination of molecular dimensions" in 1905.

The science career of Albert Einstein really took off in that year, 1905. He wrote four articles that provided the foundation of modern physics. The papers were on Brownian motion, the photoelectric effect and special relativity. He won the Nobel Prize for physics in 1921 with the paper on the photoelectric effect.

Einstein's third paper that year, "On the Electrodynamics of Moving Bodies" introduced the special theory of relativity. In the fourth paper, "Does the Inertia of a Body Depend Upon Its Energy Content?” published late in 1905, he showed that from special relativity's postulates, it is possible to deduce the famous equation: E = mc².

Einstein’s papers of 1905 were later labeled the “Annus Mirabilis Papers” (from ‘Annus mirabilis’, Latin for 'year of wonders'). This was the turning point in the career of Albert Einstein. Source: Wikipedia: Albert Einstein

From 1908 to 1912, Einstein moved considerably between academic institutions in Europe until he became full professor at the ETH Zurich in 1912. It was during this period that he published a paper on why the daytime sky is blue.

General Relativity

In November 1915, Einstein presented a series of lectures before the Prussian Academy of Sciences in which he described his theory of gravity, known as general relativity. The final lecture climaxed with his introduction of an equation that replaced Newton's law of gravity, Einstein's Field Equations. This was really the defining moment in the career of Albert Einstein.

Initially, scientists were skeptical because the general theory of relativity was not derived by experiment or observation, but by pure mathematical reasoning and rational analysis. After the 1919 confirmation of the prediction of how much the light from a star will be bent by the Sun's gravity when it passed close to the Sun, acceptance increased dramatically. On November 7, The Times reported the confirmation, cementing Einstein's fame forever.

In the early 1920s Einstein was the lead figure in a famous weekly physics colloquium at the University of Berlin. On March 30, 1921, the same year he was awarded the Nobel Prize, Einstein went to New York to give a lecture on his new Theory of Relativity.

Though he is now most famous for his work on relativity, at that time his work on general relativity was still disputed, so it was for his earlier work on the photoelectric effect that he was given the Prize. The Nobel committee decided that citing his less-contested theory in the Prize would gain better acceptance from the scientific community.

Quantum Physics

In 1917, Einstein published "On the Quantum Mechanics of Radiation". This article introduced the concept of stimulated emission, the physical principle that allows light amplification in the laser. He also published a paper that year that used the general theory of relativity to model the behavior of the entire universe, setting the stage for modern cosmology. In this work he created his self-described "worst blunder", the cosmological constant.

In the mid-1920s the original quantum theory was replaced with a new theory of quantum mechanics. Einstein balked at the Copenhagen interpretation of the new equations, either because it settled for a probabilistic, non-visualizable account of physical behavior, or because it described matter as being in necessarily contradictory states.

Einstein agreed that the theory was the best available, but he looked for a more "complete" explanation, i.e., more deterministic. He could not abandon the belief that physics described the laws that govern "real things", the belief which had led to his successes with atoms, photons, and gravity.

In a 1926 letter to Max Born, Einstein made a remark that is now famous:
"Quantum mechanics is certainly imposing. But an inner voice tells me it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the Old One. I, at any rate, am convinced that He does not throw dice."

To this, Bohr, who sparred with Einstein on quantum theory, retorted, "Stop telling God what He must do!" Bohr eventually “won” the sparring, because he could refute every criticism that Einstein had on the Copenhagen interpretation.

Einstein was not rejecting probabilistic theories per se. Einstein himself was a great statistician, using statistical analysis in his works on Brownian motion and photo-electricity and in papers published before the miraculous year 1905; Einstein had even discovered Gibbs ensembles.

He believed, however, that at the core reality behaved deterministically. Many physicists argue that experimental evidence contradicting this belief was found much later with the discovery of Bell's Theorem and the so-called 'Bell's Inequality'. Nonetheless, there is still space for lively discussions about the interpretation of quantum mechanics.

Bose-Einstein Statistics

In 1924, Einstein received a short paper from a young Indian physicist named Satyendra Nath Bose describing light as a gas of photons and asking for Einstein's assistance in publication. Einstein realized that the same statistics could be applied to atoms, and published an article in German (then the lingua franca of physics), which described Bose's model and explained its implications.

Today, Bose-Einstein statistics describe any assembly of these indistinguishable particles known as bosons. The Bose-Einstein condensate phenomenon was predicted in the 1920s by Bose and Einstein, based on Bose's work on the statistical mechanics of photons, which was then formalized and generalized by Einstein.

The first such condensate was produced by Eric Cornell and Carl Wieman in 1995 at the University of Colorado at Boulder. Einstein's original sketches on this theory were recovered in August 2005 in the library of Leiden University.

The Einstein refrigerator

Einstein and former student Leó Szilárd co-invented a unique type of refrigerator (usually called the Einstein refrigerator) in 1926. On November 11, 1930, U.S. Patent 1,781,541 was awarded to Albert Einstein and Leó Szilárd.

The machine was a single-pressure absorption refrigerator, similar in design to the gas absorption refrigerator, which are popular for camping refrigerators and freezers. The refrigeration cycle uses ammonia (pressure-equalizing fluid), butane (refrigerant), and water (absorbing fluid).

The Einstein refrigerator is portable, made of inexpensive, non-moving parts, operates silently, and is very reliable. However, leaks of the toxic ammonia caused problems in the earlier models.

The American career of Albert Einstein

When Adolf Hitler came to power in January 1933, Einstein was a guest professor at Princeton University, a position that he took in December 1932, after an invitation from the American educator, Abraham Flexner. Einstein stayed in the United States, where he was given permanent residency. He accepted a position at the newly founded Institute for Advanced Study in Princeton Township, New Jersey.

In 1939, under the encouragement of Szilárd, Einstein sent a letter to President Franklin Delano Roosevelt urging the study of nuclear fission for military purposes. This was done under fears that the Nazi government would be first to develop atomic weapons. Roosevelt started a small investigation into the matter, which eventually became the massive Manhattan Project. Einstein himself did not work on the bomb project, however.

His work at the Institute for Advanced Study focused on the unification of the laws of physics, which he referred to as the Unified Field Theory. He attempted to construct a model which would describe all of the fundamental forces as different manifestations of a single force. This took the form of an attempt to unify the gravitational and electrodynamic forces. The effort was hindered because the strong and weak nuclear forces were not understood independently until around 1970, fifteen years after Einstein's death.

Einstein’s Generalized theory

Einstein began to form a generalized theory of gravitation with the Universal Law of Gravitation and the electromagnetic force in his first attempt to demonstrate the unification and simplification of the fundamental forces. In 1950 he described his work in a Scientific American article. Einstein was guided by a belief in a single statistical measure of variance for the entire set of physical laws.

Einstein's Generalized Theory of Gravitation is a universal mathematical approach to field theory. He investigated reducing the different phenomena by the process of logic to something already known or evident. Einstein tried to unify gravity and electromagnetism in a way that also led to a new subtle understanding of quantum mechanics.

Einstein postulated a four-dimensional space-time continuum expressed in axioms represented by five component vectors. Particles appear in his research as a limited region in space in which the field strength or the energy density is particularly high.
Einstein treated subatomic particles as objects embedded in the unified field, influencing it and existing as an essential constituent of the unified field but not of it.

Einstein also investigated a natural generalization of symmetrical tensor fields, treating the combination of two parts of the field as being a natural procedure of the total field and not the symmetrical and antisymmetrical parts separately. He researched a way to delineate the equations and systems to be derived from a variational principle.

Einstein became increasingly isolated in his research on a generalized theory of gravitation and was ultimately unsuccessful in his attempts. In particular, his pursuit of a unification of the fundamental forces ignored work in the physics community at large, most notably the discovery of the strong nuclear force and weak nuclear force.

Credit: Condensed mainly out of Wikipedia: Albert_Einstein.
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