Albert Einstein
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Transcript Albert Einstein
Einstein 1905
and the birth of modern physics
Einstein Year
Einstein 1905
Nature of Light
Atomic Theory
Special Theory of Relativity
Early Years
Born in Ulm (D) 1879
Primary and secondary school (MUC)
Family move to Milan 1894
Aarau Gymnasium (SCH) 1895
ETH (ZUR) 1896
Student Years
Not a model student
Lack of interest
Diploma in maths and physics 1900
Unable to find University assistantship
Temporary schoolteaching
Bern 1901- 1905
Tech expert in Swiss Patent Office (Bern)
Swiss citizenship in 1901
Daughter with Mileva Maric in 1902
Adoption
Married in 1903
Son in 1904
Bern 1901-1905
Engineering problems (day)
Fundamental physics problems (night)
Olympia Academy of Philosophy
Arrival of Micheal Besso
Five scientific papers on thermodynamics
Contemporary Physics
Mechanics
Electromagnetism
F = ma
Law of Gravity
Elec +Mag =EM
Light = electromagnetic wave
Radiation
Planck’s Law
Radioactivity
Energy mystery
Einstein 1905
The Nature of Light
(cornerstone of quantum theory)
Atomic Theory
(reality of atoms)
Special Theory of Relativity
(physics of relative motion)
I Atomic Theory
Greeks – matter composed of atoms
Dalton – atoms of the chemical elements differ
Avogadro –atoms and molecules
Mendeleev – Periodic Table
Maxwell – Kinetic theory of gases
No direct evidence
Einstein and Atomic Theory
Molecular dimensions in liquids
Well received
Statistics of molecular motion in liquids
Fluctuations
Effect on immersed particle - Brownian motion
Mean free path calculation
Einstein and Atomic Theory
1906-08 Perrin’s Brownian Motion experiments
1908 : Confirmation of Einstein predictions
Atomic theory = reality
Role of probability and statistics in nature
Einstein established
Nobel Prize for Perrin
II Problems with Light
Radiation studies
Ultraviolet Catastrophe
Planck’s Radiation Law (1900)
“Radiation emitted/absorbed in chunks (quanta)”
Mathematical artefact
Applies only to oscillators
Einstein and Light
Einstein : inconsistency in Planck’s Law
Einstein : new statistical approach (1905)
“Light itself behaving like particles (quanta)”
Explained Planck’s law, Photoelectric Effect
Conflict with wave theory of light
Rejected for 17 years
III Relativity
Galileo: Principle of Relativity
Laws of mechanics independent of uniform motion
Impossible to detect motion internally
No absolute frame of reference for motion
Newton : absolute space
Relativity and Electromagnetism
Maxwell : electromagnetic theory
Radiation = electromagnetic waves (speed 3x108 m/s)
light = em wave of speed 3x108 m/s
Speed relative to ether ?
Absolute frame of reference for light ?
Experiments
Einstein’s Relativity 1905
Relativity applies to all laws of physics
(includes electromagnetism)
Speed of light = universal constant
(general principle)
Implication: time and distance not absolute
Implications of Special Relativity
Length of a body
Time interval
Mass of a body
L(v) L0 1 v 2 / c 2
t (v ) t 0 / 1 v 2 / c 2
m(v) m0 / 1 v 2 / c 2
Implications of SR
Time is relative
Time + space = spacetime
Mass is a form of energy
E = mc2
Response to relativity
Controversy (1905-08)
Kaufmann experiments (1908)
Bucherer experiments (1909)
By 1911 Special Relativity accepted
Career Progress
1905 PhD (ETH)
1908 Privatdozent (Univ Bern)
1909 Assoc Prof (Univ Zurich)
1911 Prof (Univ Prague)
1912 Prof (ETH Zurich)
1914 Prof (Univ Berlin), Director (FW Institute)
1913 Separation
Middle Years (1908-1916)
Relativity and accelerated bodies (1908-15)
Principle of Equivalence
General Relativity (1915)
“Gravity = curvature of space-time”
Bending of light by gravity
Slowing of time by gravity
Cosmological implications
After the War
1916 Photoelectric effect
1919 Evidence for GR
1921 Nobel Prize
(Millikan)
(Eddington)
(Photoelectric effect)
1923 Compton Effect
(light quanta)
1925 Electron waves
(quantum duality)
Between Wars
1919
1920s
1930-33
Remarried
Anti-semitism in Germany
Einstein’s work attacked
Rise of Nazi Party
1930-33 Visiting Prof at Caltech (US)
1933
Hitler assumes power
1933
Flight to Princeton (US)
Princeton Years (1933-55)
Hero’s Welcome
American Icon
Letter to Roosevelt (1939)
Manhattan Project
Regret at Hiroshima (1944)
Nuclear disarmament (1940s)
McCarthyism (1950s)
Princeton Years (1933-55)
Interpretation of quantum theory
Relativity and electromagnetism
Unified Field Theory
Evidence for relativity (1950s)
New York Times
Iconic figure
Einstein Today
Atomic Theory
Reality of atoms
Stat. applications
Quantum Theory
Wave/particle duality
Applications
Special Relativity
Particle physics
Nuclear fission and fusion
Einstein Today
General Relativity
Unified Field Theory
Underlies cosmology
Evolution of Universe
Still not solved
Holy grail of physics