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
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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
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Time is relative
Time + space = spacetime
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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)
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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)
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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