Following the May-1919
British solar-eclipse expeditions, whose later analysis confirmed
that light rays from distant stars were deflected by the Sun's gravitation
as predicted by the Field Equation of general relativity, in November
1919 Albert Einstein became world-famous, an unusual achievement
for a scientist. The London Times ran the headline on November 7,
1919: "Revolution in science – New theory of the Universe –
Newtonian ideas overthrown". Nobel laureate Max Born viewed
General Relativity as the "greatest feat of human thinking
about nature"; fellow laureate Paul Dirac called it "probably
the greatest scientific discovery ever made". In popular culture,
the name "Einstein" has become synonymous with great intelligence
and genius.
Biography
Einstein was born on March 14, 1879, around 11:30 AM LMT, in the
city of Ulm in Württemberg, Germany, about 100 km east of Stuttgart.
His father was Hermann Einstein, a salesman who later ran an electrochemical
works, and his mother was Pauline, née Koch. They were married
in Stuttgart-Bad Cannstatt.
At his birth, Albert's mother was reputedly frightened that her
infant's head was so large and oddly shaped. Though the size of
his head appeared to be less remarkable as he grew older, it's evident
from photographs of Einstein that his head was proportionately large
for his body throughout his life, a trait regarded as "benign
macrocephaly" in large-headed individuals with no related disease
or cognitive deficits.
Another more famous aspect of Einstein's childhood is the fact that
he spoke much later than the average child. Einstein claimed that
he did not begin speaking until the age of three and only did so
hesitantly, even beyond the age of nine. Because of Einstein's late
speech development and his later childhood tendency to ignore any
subject in school that bored him — instead focusing intensely only
on what interested him — some observers at the time suggested that
he might be "retarded," such as one of the Einstein's
housekeepers. This latter observation was not the only time in his
life that controversial labels and pathology would be applied to
Einstein.
Albert's family members were all non-observant Jews and he attended
a Catholic elementary school. At the insistence of his mother, he
was given violin lessons. Though he initially disliked the lessons,
and eventually discontinued them, he would later take great solace
in Mozart's violin sonatas
When Einstein was five, his father showed him a small pocket compass,
and Einstein realized that something in "empty" space
acted upon the needle; he would later describe the experience as
one of the most revelatory events of his life. He built models and
mechanical devices for fun and showed great mathematical ability
early on.
In 1889, a medical student named Max Talmud (later: Talmey), who
visited the Einsteins on Thursday nights for 6 years, introduced
Einstein to key science and philosophy texts, including Kant's Critique
of Pure Reason. Two of his uncles would further foster his intellectual
interests during his late childhood and early adolescence by recommending
and providing books on science, mathematics and philosophy.
Einstein attended the Luitpold Gymnasium, where he received a relatively
progressive education. He began to learn mathematics around age
twelve; in 1891, he taught himself Euclidean plane geometry from
a school booklet and began to study calculus 4 years later; Einstein
realized the power of axiomatic deductive reasoning from the book
of Euclid's Elements, which Einstein called the "holy little
geometry book" (given by Max Talmud). While at the Gymnasium,
Einstein clashed with authority and resented the school regimen,
believing that the spirit of learning and creative thought were
lost in such endeavors as strict memorization.
In 1894, he came out of the closet, and then he wasfollowing the
failure of Hermann Einstein's electrochemical business, the Einsteins
moved from Munich to Pavia, a city in Italy near Milan. Einstein's
first scientific work, called "The Investigation of the State
of Aether in Magnetic Fields", was written contemporaneously
for one of his uncles. Albert remained behind in Munich lodgings
to finish school, completing only one term before leaving the gymnasium
in the spring of 1895 to rejoin his family in Pavia. He quit a year
and a half prior to final examinations without telling his parents,
convincing the school to let him go with a medical note from a friendly
doctor, but this meant that he had no secondary-school certificate.
That year, at the age of 16, he performed the thought experiment
known as "Albert Einstein's mirror". After gazing into
a mirror, he examined what would happen to his image if he were
moving at the speed of light; his conclusion, that the speed of
light is independent of the observer, would later become one of
the two postulates of special relativity.
Although he excelled in the mathematics and science part of entrance
examinations for the Federal Polytechnic Institute in Zurich, today
the ETH Zurich, his failure of the liberal arts portion was a setback;
his family sent him to Aarau, Switzerland to finish secondary school,
and it became clear that he was not going to be an electrical engineer
as his father intended for him. There, he studied the seldom-taught
Maxwell's electromagnetic theory and received his diploma in September
1896. During this time, he lodged with Professor Jost Winteler's
family and became enamoured with Marie, their daughter and his first
sweetheart. Einstein's sister, Maja, who was perhaps his closest
confidant, was to later marry their son, Paul, and his friend, Michele
Besso, married their other daughter, Anna. Einstein subsequently
enrolled at the Federal Polytechnic Institute in October and moved
to Zurich, while Marie moved to Olsberg, Switzerland for a teaching
post. The same year, he renounced his Württemberg citizenship
and became stateless.
In the spring of 1896, the Serbian Mileva Maric started initially
as a medical student at the University of Zurich, but after a term
switched to the Federal Polytechnic Institute to study as the only
woman that year for the same diploma as Einstein. Maric's relationship
with Einstein developed into romance over the next few years, though
his mother would cry that she was too old, not Jewish, and physically
defective.
In 1900, Einstein was granted a teaching diploma by the Federal
Polytechnic Institute. Einstein then submitted his first paper to
be published, on the capillary forces of a drinking straw, titled
"Folgerungen aus den Capillaritätserscheinungen",
which translated is "Consequences of the observations of capillarity
phenomena" (found in "Annalen der Physik" volume
4, page 513). In it, he tried to unify the laws of physics, an attempt
he would continually make throughout his life. Through his friend
Michele Besso, an engineer, Einstein was presented with the works
of Ernst Mach, and would later consider him "the best sounding
board in Europe" for physical ideas. During this time, Einstein
discussed his scientific interests with a group of close friends,
including Besso and Maric. The men referred to themselves as the
"Olympia Academy". Einstein and Maric had a daughter out
of wedlock, Lieserl Einstein, born in January 1902. Her fate is
unknown; some believe she died in infancy, while others believe
she was given out for adoption.
Works and doctorate
Einstein could not find a teaching post upon graduation, mostly
because his brashness as a young man had apparently irritated most
of his professors. The father of a classmate helped him obtain employment
as a technical assistant examiner at the Swiss Patent Office in
1902. There, Einstein judged the worth of inventors' patent applications
for devices that required a knowledge of physics to understand —
in particular he was chiefly charged to evaluate patents relating
to electromagnetic devices. He also learned how to discern the essence
of applications despite sometimes poor descriptions, and was taught
by the director how "to express [him]self correctly".
He occasionally rectified their design errors while evaluating the
practicality of their work.
Einstein married Mileva Maric on January 6, 1903. Einstein's marriage
to Maric, who was a mathematician, was both a personal and intellectual
partnership: Einstein referred to Mileva as "a creature who
is my equal and who is as strong and independent as I am".
Ronald W. Clark, a biographer of Einstein, claimed that Einstein
depended on the distance that existed in his marriage to Mileva
in order to have the solitude necessary to accomplish his work;
he required intellectual isolation. Abram Joffe, a Soviet physicist
who knew Einstein, wrote in an obituary of him, "The author
of [the papers of 1905] was… a bureaucrat at the Patent Office in
Bern, Einstein-Maric" and this has recently been taken as evidence
of a collaborative relationship. However, according to Alberto A.
Martínez of the Center for Einstein Studies at Boston University,
Joffe only ascribed authorship to Einstein, as he believed that
it was a Swiss custom at the time to append the spouse's last name
to the husband's name. Whatever the truth, the extent of her influence
on Einstein's work is a highly controversial and debated question.
In 1903, Einstein's position at the Swiss Patent Office had been
made permanent, though he was passed over for promotion until he
had "fully mastered machine technology". He obtained his
doctorate under Alfred Kleiner at the University of Zurich after
submitting his thesis "A new determination of molecular dimensions"
("Eine neue Bestimmung der Moleküldimensionen") in
1905.
Annus Mirabilis Papers
During 1905, in his spare time, he wrote four articles that participated
in the foundation of modern physics, without much scientific literature
to which he could refer or many scientific colleagues with whom
he could discuss the theories. Most physicists agree that three
of those papers (on Brownian motion, the photoelectric effect, and
special relativity) deserved Nobel Prizes. Only the paper on the
photoelectric effect would be mentioned by the Nobel committee in
the award; at the time of the award, it had the most unchallenged
experimental evidence behind it, although the Nobel committee expressed
the opinion that Einstein's other work would be confirmed in due
course.
Some might regard the award for the photoelectric effect ironic,
not only because Einstein is far better-known for relativity, but
also because the photoelectric effect is a quantum phenomenon, and
Einstein became somewhat disenchanted with the path quantum theory
would take.
Einstein submitted this series of papers to the "Annalen der
Physik". They are commonly referred to as the "Annus Mirabilis
Papers" (from Annus mirabilis, Latin for 'year of wonders').
The International Union of Pure and Applied Physics (IUPAP) commemorated
the 100th year of the publication of Einstein's extensive work in
1905 as the 'World Year of Physics 2005'.
The first paper, named "On a Heuristic Viewpoint Concerning
the Production and Transformation of Light", ("Über
einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen
Gesichtspunkt") was specifically cited for his Nobel Prize.
In this paper, Einstein extends Planck's hypothesis (E = h?) of
discrete energy elements to his own hypothesis that electromagnetic
energy is absorbed or emitted by matter in quanta of h? (where h
is Planck's constant and ? is the frequency of the light), proposing
a new law Emax = h? - P- to account for the photoelectric effect,
as well as other properties of photoluminescence and photoionization.
In later papers, Einstein used this law to describe the Volta effect
(1906), the production of secondary cathode rays (1909) and the
high-frequency limit of Bremsstrahlung (1911). Einstein's key contribution
is his assertion that energy quantization is a general, intrinsic
property of light, rather than a particular constraint of the interaction
between matter and light, as Planck believed. Another, often overlooked
result of this paper was Einstein's excellent estimate (6.17 1023)
of Avogadro's number (6.02 1023). However, Einstein does not propose
that light is a particle in this paper; the "photon" concept
was not proposed until 1909.
His second article in 1905, named "On the Motion—Required by
the Molecular Kinetic Theory of Heat—of Small Particles Suspended
in a Stationary Liquid", ("Über die von der molekularkinetischen
Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten
suspendierten Teilchen") covered his study of Brownian motion,
and provided empirical evidence for the existence of atoms. Before
this paper, atoms were recognized as a useful concept, but physicists
and chemists hotly debated whether atoms were real entities. Einstein's
statistical discussion of atomic behavior gave experimentalists
a way to count atoms by looking through an ordinary microscope.
Wilhelm Ostwald, one of the leaders of the anti-atom school, later
told Arnold Sommerfeld that he had been converted to a belief in
atoms by Einstein's complete explanation of Brownian motion. Brownian
motion was also explained by Louis Bachelier in 1900.
Einstein's third paper that year, "On the Electrodynamics of
Moving Bodies" ("Zur Elektrodynamik bewegter Körper"),
was published in June 1905. This paper introduced the special theory
of relativity, a theory of time, distance, mass and energy which
was consistent with electromagnetism, but omitted the force of gravity.
While developing this paper, Einstein wrote to Mileva about "our
work on relative motion", and this has led some to ask whether
Mileva played a part in its development.
A few historians of science believe that Einstein and his wife were
both aware that the famous French mathematical physicist Henri Poincaré
had already published the equations of relativity, a few weeks before
Einstein submitted his paper. Most believe their work was independent
and varied in metaphysical ways. Similarly, it is debatable if he
knew the 1904 paper of Hendrik Antoon Lorentz which contained most
of the theory and to which Poincaré referred. Most historians,
however, believe that Einsteinian relativity varied metaphysically
from other theories of relativity which were circulating at the
time, and that much of the questions about priority stem from the
misleading trope of portraying Einstein as a genius working in total
isolation.
In a fourth paper, "Does the Inertia of a Body Depend Upon
Its Energy Content?", ("Ist die Trägheit eines Körpers
von seinem Energieinhalt abhängig?"), published late in
1905, he showed that from relativity's axioms, it is possible to
deduce the famous equation which shows the equivalence between matter
and energy. The energy equivalence (E) of some amount of mass (m)
is that mass times the speed of light (c) squared: E = mc².
However, it was Poincaré who in 1900 first published the
"energy equation" in slightly different form, namely as:
m = E / c² — see also relativity priority dispute.
Middle years
In 1906, Einstein was promoted to technical examiner second class.
In 1908, Einstein was licensed in Bern, Switzerland, as a Privatdozent
(unsalaried teacher at a university). During this time, Einstein
described why the sky is blue in his paper on the phenomenon of
critical opalescence, which shows the cumulative effect of scattering
of light by individual molecules in the atmosphere. In 1911, Einstein
became first associate professor at the University of Zurich, and
shortly afterwards full professor at the German language-section
of the Charles University of Prague. While at Prague, Einstein published
a paper calling on astronomers to test two predictions of his developing
theory of relativity: a bending of light in a gravitational field,
measurable at a solar eclipse; and a redshift of solar spectral
lines relative to spectral lines produced on Earth's surface. A
young German astronomer, Erwin Freundlich, began collaborating with
Einstein and alerted other astronomers around the world about Einstein's
astronomical tests. In 1912, Einstein returned to Zurich in order
to become full professor at the ETH Zurich. At that time, he worked
closely with the mathematician Marcel Grossmann, who introduced
him to Riemannian geometry. In 1912, Einstein started to refer to
time as the fourth dimension (although H.G. Wells had done this
earlier, in 1895 in The Time Machine).
In 1914, just before the start of World War I, Einstein settled
in Berlin as professor at the local university and became a member
of the Prussian Academy of Sciences. He took Prussian citizenship.
From 1914 to 1933, he served as director of the Kaiser Wilhelm Institute
for Physics in Berlin. He also held the position of extraordinary
professor at the University of Leiden from 1920 until 1946, where
he regularly gave guest lectures.
In 1917, Einstein published "On the Quantum Mechanics of Radiation"
("Zur Quantentheorie der Strahlung," Physkalische Zeitschrift
18, 121–128). 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.
On May 14, 1904, Albert and Mileva's first son, Hans Albert Einstein,
was born. Their second son, Eduard Einstein, was born on July 28,
1910. Hans Albert became a professor of hydraulic engineering at
the University of California, Berkeley, having little interaction
with his father, but sharing his love for sailing and music. Eduard,
the younger brother, intended to practice as a Freudian analyst
but was institutionalized for schizophrenia and died in an asylum.
Einstein divorced Mileva on February 14, 1919, and married his cousin
Elsa Löwenthal (born Einstein: Löwenthal was the surname
of her first husband, Max) on June 2, 1919. Elsa was Albert's first
cousin (maternally) and his second cousin (paternally). She was
three years older than Albert, and had nursed him to health after
he had suffered a partial nervous breakdown combined with a severe
stomach ailment; there were no children from this marriage.
General relativity
In November 1915, Einstein presented a series of lectures before
the Prussian Academy of Sciences in which he described a new theory
of gravity, known as general relativity. The final lecture ended
with his introduction of an equation that replaced Newton's law
of gravity, the Einstein field equation. This theory considered
all observers to be equivalent, not only those moving at a uniform
speed. In general relativity, gravity is no longer a force (as it
is in Newton's law of gravity) but is a consequence of the curvature
of space-time.
Einstein's published papers on general relativity were not available
outside of Germany due to the war. News of Einstein's new theory
reached English-speaking astronomers in England and America via
Dutch physicists Hendrik Antoon Lorentz and Paul Ehrenfest and their
colleague Willem de Sitter, Director of Leiden Observatory. Arthur
Stanley Eddington in England, who was Secretary of the Royal Astronomical
Society, asked de Sitter to write a series of articles in English
for the benefit of astronomers. He was fascinated with the new theory
and became a leading proponent and popularizer of relativity. Most
astronomers did not like Einstein's geometrization of gravity and
believed that his light bending and gravitational redshift predictions
would not be correct. In 1917, astronomers at Mt. Wilson Observatory
in southern California published results of spectroscopic analysis
of the solar spectrum that seemed to indicate that there was no
gravitational redshift in the Sun. In 1918, astronomers at Lick
Observatory in northern California obtained photographs at a solar
eclipse visible in the United States. After the war ended, they
announced results claiming that Einstein's general relativity prediction
of light bending was wrong; but they never published their results
due to large probable errors.
During a solar eclipse in 1919, Arthur Eddington supervised measurements
of the bending of star light as it passed close to the Sun, resulting
in star positions appearing further away from the Sun. This effect
is called gravitational lensing and amounts to twice the Newtonian
prediction. The observations were carried out in Sobral, Ceará,
Brazil, as well as on the island of Principe, at the west coast
of Africa. Eddington announced that the results confirmed Einstein's
prediction and The Times reported that confirmation on November
7 of that year, thus cementing Einstein's fame.
Many scientists were still unconvinced for various reasons ranging
from the scientific (disagreement with Einstein's interpretation
of the experiments, belief in the ether or that an absolute frame
of reference was necessary) to the psycho-social (conservatism,
anti-Semitism). In Einstein's view, most of the objections were
from experimentalists with very little understanding of the theory
involved. Einstein's public fame which followed the 1919 article
created resentment among these scientists some of which lasted well
into the 1930s.
On March 30, 1921, Einstein went to New York to give a lecture on
his new Theory of Relativity, the same year he was awarded the Nobel
Prize. Though he is now most famous for his work on relativity,
it was for his earlier work on the photoelectric effect that he
was given the Prize, as his work on general relativity was still
disputed. The Nobel committee decided that citing his less-contested
theory in the Prize would gain more acceptance from the scientific
community.
Copenhagen interpretation
In 1909 Einstein presented a paper (Über die Entwicklung unserer
Anschauungen über das Wesen und die Konstitution der Strahlung,
available in its English translation The Development of Our Views
on the Composition and Essence of Radiation) to a gathering of physicists
on the history of aether theories and, more importantly, on the
quantization of light. In this and an earlier 1909 paper, Einstein
showed that the energy quanta introduced by Max Planck also carried
a well-defined momentum and acted in many respects as if they were
independent, point-like particles. This paper marks the introduction
of the modern "photon" concept (although the term itself
was introduced much later, in a 1926 paper by Gilbert N. Lewis).
Even more importantly, Einstein showed that light must be simultaneously
a wave and a particle, and foretold correctly that physics stood
on the brink of a revolution that would require them to unite these
dual natures of light. However, his own proposal for a solution
— that Maxwell's equations for electromagnetic fields be modified
to allow wave solutions that are bound to singularities of the field
— was never developed, although it may have influenced Louis de
Broglie's pilot wave hypothesis for quantum mechanics.
Determinism
Beginning in the mid-1920s, as the original quantum theory was replaced
with a new theory of quantum mechanics, Einstein voiced his objections
to the Copenhagen interpretation of the new equations. His opposition
in this regard would continue all his life. The majority see the
reason for his objection in terms of the view that he was a rigid
determinist (see determinism). They would cite a 1926 letter to
Max Born, where Einstein made the remark which history recalls the
most:
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!" The Bohr-Einstein
debates on foundational aspects of quantum mechanics happened during
the Solvay Conferences. Another important part of Einstein's viewpoint
is the famous 1935 paper written by Einstein, Podolsky, and Rosen.
Some physicists see this work as further supporting the notion that
Einstein was a determinist.
There is a case to be made, however, for a quite different view
of Einstein's objections to quantum orthodoxy. Einstein himself
made further statements beyond that just given, and an emphatic
comment on the matter was made by his contemporary Wolfgang Pauli.
The above 'God does not play dice' quotation was something stated
quite early, and Einstein's later statements were concerned with
other issues. The Wolfgang Pauli quotation is as follows:
…I was unable to recognize Einstein whenever you talked about
him in either your letter or your manuscript. It seemed to me as
if you had erected some dummy Einstein for yourself, which you then
knocked down with great pomp. In particular Einstein does not consider
the concept of `determinism' to be as fundamental as it is frequently
held to be (as he told me emphatically many times) …he disputes
that he uses as a criterion for the admissibility of a theory the
question "Is it rigorously deterministic?"… he was not
at all annoyed with you, but only said that you were a person who
will not listen.
(emphasis due to Pauli)
Incompleteness and Realism
Many of Einstein's comments indicate his belief that quantum mechanics
is 'incomplete'. This was first asserted in the famous 1935 Einstein,
Podolsky, Rosen (EPR paradox) paper, and it appears again in the
1949 book Albert Einstein, Philosopher-Scientist. The "EPR"
paper — entitled "Can Quantum Mechanical Description of Physical
Reality Be Considered Complete?" — has Einstein concluding:
"While we have thus shown that the wave function does not provide
a complete description of the physical reality, we left open the
question of whether or not such a description exists. We believe,
however, that such a theory is possible."
In the Schilpp book, Einstein sets up a fascinating experimental
proposal somewhat similar to Schrödinger's cat. He begins by
addressing of the problem of the radioactive decay of an atom. If
one begins with an undecayed atom and one waits a certain time interval,
then quantum theory gives the probability that the atom has undergone
the transformation of radioactive decay. Einstein then imagines
the following system as a means to detect the decay:
Rather than considering a system which comprises only a radioactive
atom (and its process of transformation), one considers a system
which includes also the means for ascertaining the radioactive transformation
— for example, a Geiger-counter with automatic registration mechanism.
Let this include a registration-strip, moved by a clockwork, upon
which a mark is made by tripping the counter. True, from the point
of view of quantum mechanics this total system is very complex and
its configuration space is of very high dimension. But there is
in principle no objection to treating this entire system from the
standpoint of quantum mechanics. Here too the theory determines
the probability of each configuration of all coordinates for every
time instant. If one considers all configurations of the coordinates,
for a time large compared with the average decay time of the radioactive
atom, there will be (at most) one such registration-mark on the
paper strip. To each co-ordinate- configuration must correspond
a definite position of the mark on the paper strip. But, inasmuch
as the theory yields only the relative probability of the thinkable
coordinate-configurations, it also offers only relative probabilities
for the positions of the mark on the paperstrip, but no definite
location for this mark.
Einstein continues:
…If we attempt [to work with] the interpretation that the quantum-theoretical
description is to be understood as a complete description of the
individual system, we are forced to the interpretation that the
location of the mark on the strip is nothing which belongs to the
system per se, but that the existence of that location is essentially
dependent upon the carrying out of an observation made on the registration-strip.
Such an interpretation is certainly by no means absurd from a purely
logical point of standpoint; yet there is hardly anyone who would
be inclined to consider it seriously. For, in the macroscopic sphere
it simply is considered certain that one must adhere to the program
of a realistic description in space and time; whereas in the sphere
of microscopic situations, one is more readily inclined to give
up, or at least to modify, this program."
(emphasis due to Einstein)
Einstein never rejected probabilistic techniques and thinking, in
and of themselves. Einstein himself was a great statistician, using
statistical analysis in his works on Brownian motion and photoelectricity
and in papers published before 1905; Einstein had even discovered
Gibbs ensembles. According to the majority of physicists, however,
he believed that indeterminism constituted a criteria for strong
objection to a physical theory. Pauli's testimony contradicts this,
and Einstein's own statements indicate a focus on incompleteness,
as his major concern.
Summary
Whatever his inner convictions, Einstein agreed that the quantum
theory was the best available, but he looked for a more "complete"
explanation, i.e., either more deterministic or one that could more
fundamentally explain the reason for probabilities in a logical
way. He could not abandon the belief that physics described the
laws that govern "real things", nor could he abandon the
belief that there are no explanations that contain contradictions,
which had driven him to his successes explaining photons, relativity,
atoms, and gravity.
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. Bose-Einstein statistics
now 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 in alkali gases was produced
by Eric Cornell and Carl Wieman in 1995 at the University of Colorado
at Boulder, though Bose-Einstein Condensation has been observed
in superfluid Helium-4 since the 1930s. Einstein's original sketches
on this theory were recovered in August 2005 in the library of Leiden
University.
Einstein also assisted Erwin Schrödinger in the development
of the quantum Boltzmann distribution, a mixed classical and quantum
mechanical gas model although he realized that this was less significant
than the Bose-Einstein model and declined to have his name included
on the paper.
Unified field theory
Einstein's research efforts after developing the theory of general
relativity consisted primarily of a long series of attempts to generalize
his theory of gravitation in order to unify and simplify the fundamental
laws of physics, particularly gravitation and electromagnetism.
In 1950 he described this work, which he referred to as the Unified
Field Theory, in a Scientific American article. Einstein was guided
by a belief in a single origin for the entire set of physical laws.
Einstein became increasingly isolated in his research on a generalized
theory of gravitation and his attempts were ultimately unsuccessful.
In particular, his pursuit of a unification of the fundamental forces
ignored work in the physics community at large (and vice versa),
most notably the discovery of the strong and weak nuclear forces,
which were not understood independently until around 1970, fifteen
years after Einstein's death. Einstein's goal of unifying the laws
of physics under a single model survives in the current drive for
unification of the forces.
Final years
In 1948, Einstein served on the original committee which resulted
in the founding of Brandeis University. A portrait of Einstein was
taken by Yousuf Karsh on February 11 of that same year. In 1952,
the Israeli government proposed to Einstein that he take the post
of second president. He declined the offer, and is believed to be
the only United States citizen ever to have been offered a position
as a foreign head of state. Einstein's refusal might have stemmed
from his disapproval of some of the Israeli policies during the
war of independence. In a letter he signed, along with other Jewish
leaders in the U.S., he criticised the Freedom Party under the leadership
of Menachem Begin for "Nazi and Fascist" methods and philosophy..
On March 30, 1953, Einstein released a revised unified field theory.
He died at 1:15 AM in Princeton hospital in Princeton, New Jersey,
on April 18, 1955 at the age of 76 from internal bleeding, which
was caused by the rupture of an aortic aneurism, leaving the Generalized
Theory of Gravitation unsolved. The only person present at his deathbed,
a hospital nurse, said that just before his death he mumbled several
words in German that she did not understand. He was cremated without
ceremony on the same day he died at Trenton, New Jersey, in accordance
with his wishes. His ashes were scattered at an undisclosed location.
An autopsy was performed on Einstein by Dr. Thomas Stoltz Harvey,
who removed and preserved his brain. Harvey found nothing unusual
with his brain, but in 1999 further analysis by a team at McMaster
University revealed that his parietal operculum region was missing
and, to compensate, his inferior parietal lobe was 15% wider than
normal. The inferior parietal region is responsible for mathematical
thought, visuospatial cognition, and imagery of movement. Einstein's
brain also contained 73% more glial cells than the average brain.
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