Absorption Probability Coefficient Defined
Einstein represented the probability of an atom absorbing incident radiation and moving to a higher energy state with a coefficient proportional to the surrounding radiation density.
Albert Einstein · Year
1916
Albert Einstein records dated 1916, drawn directly from the World History Database source collection.
Atomic Transition Probabilities Introduced
Einstein formulated radiation processes in terms of probabilities for transitions between atomic energy states, creating a statistical framework for absorption and emission.
Detailed Balance Applied to Matter and Radiation
Einstein required upward and downward atomic transitions to balance in thermal equilibrium, using that condition to connect transition probabilities with the equilibrium radiation spectrum.
Energy Conservation in General Relativity
Develops the treatment of energy and momentum in the gravitational field, addressing how conservation laws operate within the generally covariant theory.
Foundation of General Relativity
Publishes a systematic presentation of the general theory of relativity and its field equations.
General Relativity Review Article Published
Einstein published a comprehensive exposition of general relativity that assembled the geometric framework, field equations and physical consequences into a systematic theory.
Geodesic Motion Described in Curved Spacetime
Einstein's mature theory described freely falling bodies as following the straightest possible world-lines through curved spacetime rather than being pulled by a Newtonian gravitational force.
German Physical Society Presidency
Serves as president of the German Physical Society during the consolidation of general relativity.
Gravitational Energy Flux Treated with Pseudotensor
Einstein developed a gravitational energy-momentum construction to discuss how changing gravitational fields can transport energy despite the special conservation difficulties of general relativity.
Gravitational Waves Propagate at Light Speed
Einstein's wave analysis showed that physical gravitational disturbances in the relativistic theory propagate through empty space at the speed of light.
Hamilton Principle for General Relativity
Formulates general relativity using Hamilton's variational principle, providing a compact mathematical route to the gravitational field equations and their conservation properties.
Kottler Equivalence Hypothesis Response
Responds to Friedrich Kottler's criticism of the equivalence hypothesis, defending the conceptual basis on which his route from special to general relativity depended.
Nonlinearity of Gravitational Field Established
Einstein's field equations made gravity nonlinear, so the gravitational field contributes to the dynamics instead of behaving as a simple superposition of independent Newtonian forces.
Planck Spectrum Recovered from Transition Statistics
Einstein showed that his statistical rules for absorption, spontaneous emission and induced emission can reproduce Planck's black-body radiation law under thermal equilibrium.
Quantum Theory of Radiation
Develops a quantum theory of radiation introducing transition probabilities later represented by Einstein coefficients.
Radiative Transitions Linked to Discrete Energy Differences
Einstein treated the frequency of absorbed or emitted radiation as fixed by the discrete energy difference between the participating atomic states.
Spontaneous Emission Probability Defined
Einstein introduced a coefficient describing the probability that an excited atom will emit radiation spontaneously and fall to a lower energy state.
Stimulated Emission Probability Coefficient Defined
Einstein introduced a second radiation-dependent transition probability in which incident radiation stimulates an excited atom to emit additional radiation.
Stress-Energy Identified as Source of Curvature
General relativity connected spacetime curvature with the energy, momentum and stresses of matter, making the physical contents of the universe sources of the gravitational geometry.
Weak-Field Gravitational Waves Derived
Einstein linearised the gravitational field equations in the weak-field limit and identified wave-like disturbances capable of propagating through spacetime.
Schwarzschild Solution Presented to Academy
Communicates Karl Schwarzschild's exact solution of the new field equations to the Prussian Academy, demonstrating that general relativity admits important exact solutions.
Gravitational Waves
Predicts gravitational waves as propagating disturbances in spacetime within general relativity.
Relativity: The Special and General Theory
Publishes his popular introduction to special and general relativity.