Hendrik Lorentz
Hendrik Antoon Lorentz was a Dutch theoretical physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for their discovery and theoretical explanation of the Zeeman effect. He derived the Lorentz transformation of the special theory of relativity, as well as the Lorentz force, which describes the force acting on a charged particle in an electromagnetic field. He was also responsible for the Lorentz oscillator model, a classical model used to describe the anomalous dispersion observed in dielectric materials when the driving frequency of the electric field was near the resonant frequency of the material, resulting in abnormal refractive indices.
Lorentz received many other honors and distinctions, including a term as Chairman of the International Committee on Intellectual Cooperation, the forerunner of UNESCO, from 1925 until his death in 1928.
Early life and education
Hendrik Antoon Lorentz was born on 18 July 1853 in Arnhem, Netherlands, as the son of Gerrit Frederik Lorentz and Geertruida van Ginkel. In 1862, after his mother's death, his father married Luberta Hupkes. Despite being raised as a Protestant, he was a freethinker in religious matters and regularly attended Catholic mass at his local French church.From 1866 to 1869, Lorentz attended the Hogere Burgerschool in Arnhem, a new type of public high school recently established by Johan Thorbecke. His results in school were exemplary; not only did he excel in the physical sciences and mathematics, but also in English, French, and German. In 1870, he passed the exams in classical languages, which were then required for admission to university.
In 1870, Lorentz entered Leiden University, where he was strongly influenced by the teaching of astronomy professor Frederik Kaiser; it was his influence that led Lorentz to become a physicist. The following year, he obtained a B.Sc. in Mathematics and Physics. In 1872, he returned to Arnhem to become a night school teacher, while also continuing his studies at Leiden. In 1875, he received his Ph.D. under Pieter Rijke with a thesis on the reflection and refraction of light, in which he refined the electromagnetic theory of James Clerk Maxwell.
Career
In 1878, Lorentz was appointed to the newly established Chair of Theoretical Physics at Leiden University; the position had initially been offered to Johannes van der Waals, but he had just accepted a professorship at the University of Amsterdam. On 25 January 1878, he delivered his inaugural lecture titled De moleculaire theoriën in de natuurkunde.During his first 20 years at Leiden, Lorentz was primarily interested in the electromagnetic theory of electricity, magnetism, and light. After that, he extended his research to a much wider area while still focusing on theoretical physics. He made significant contributions to fields ranging from hydrodynamics to general relativity. His most important contributions were in the area of electromagnetism, the electron theory, and relativity.
In 1910, Lorentz decided to reorganize his career; his teaching and management duties at Leiden University were taking up too much of his time, leaving him little time for research. He initially asked Albert Einstein to succeed him as Professor of Theoretical Physics at Leiden. However, Einstein did not accept, because he had just taken up a position at ETH Zurich and the prospect of having to fill Lorentz's shoes made him shiver. He ultimately chose Paul Ehrenfest as his successor.
In 1912, Lorentz resigned from his chair at Leiden University to become Curator of the Physical Cabinet at Teylers Museum in Haarlem. He continued to teach at Leiden as Extraordinary Professor, delivering his famous "Monday morning lectures" on new developments in theoretical physics.
Research
Electrodynamics and relativity
In 1892 and 1895, Lorentz worked on describing electromagnetic phenomena in reference frames that move relative to the postulated luminiferous aether. He discovered that the transition from one to another reference frame could be simplified by using a new time variable that he called local time and which depended on universal time and the location under consideration. Although he did not give a detailed interpretation of the physical significance of local time, with it, he could explain the aberration of light and the result of the Fizeau experiment. In 1900 and 1904, Henri Poincaré called local time Lorentz's "most ingenious idea" and illustrated it by showing that clocks in moving frames are synchronized by exchanging light signals that are assumed to travel at the same speed against and with the motion of the frame. In 1892, with the attempt to explain the Michelson–Morley experiment, he also proposed that moving bodies contract in the direction of motion.In 1899 and again in 1904, Lorentz added time dilation to his transformations and published what Poincaré in 1905 named Lorentz transformations.
It was apparently unknown to Lorentz that Joseph Larmor had used identical transformations to describe orbiting electrons in 1897. Larmor's and Lorentz's equations look somewhat dissimilar, but they are algebraically equivalent to those presented by Poincaré and Einstein in 1905. Lorentz's 1904 paper includes the covariant formulation of electrodynamics, in which electrodynamic phenomena in different reference frames are described by identical equations with well defined transformation properties. The paper clearly recognizes the significance of this formulation, namely that the outcomes of electrodynamic experiments do not depend on the relative motion of the reference frame. The 1904 paper includes a detailed discussion of the increase of the inertial mass of rapidly moving objects in a useless attempt to make momentum look exactly like Newtonian momentum; it was also an attempt to explain the length contraction as the accumulation of "stuff" onto mass making it slow and contract.
Zeeman effect
Lorentz theorized that atoms consist of charged particles, and suggested that the oscillations of these charged particles were the source of light. His colleague and former student, Pieter Zeeman, discovered the Zeeman effect in 1896, and Lorentz supplied its theoretical interpretation. Their joint work earned them the Nobel Prize in Physics in 1902.Special relativity
]In 1905, Einstein would use many of the concepts, mathematical tools and results Lorentz discussed to write his paper titled Zur Elektrodynamik bewegter Körper, known today as the special theory of relativity. Because Lorentz laid the fundamentals for the work by Einstein, this theory was originally called the Lorentz–Einstein theory.
In 1906, Lorentz's electron theory received a full-fledged treatment in his lectures at Columbia University, published under the title The Theory of Electrons.
The increase of mass was the first prediction of Lorentz and Einstein to be tested, but some experiments by Walter Kaufmann appeared to show a slightly different mass increase; this led Lorentz to the famous remark that he was "au bout de mon latin" The confirmation of his prediction had to wait until 1908 and later.
Lorentz published a series of papers dealing with what he called "Einstein's principle of relativity". For instance, in 1909, 1910, 1914. In his 1906 lectures published with additions in 1909 in the book "The theory of electrons", he spoke affirmatively of Einstein's theory:
Though Lorentz still maintained that there is an aether in which resting clocks indicate the "true time":
Lorentz also gave credit to Poincaré's contributions to relativity.
General relativity
Lorentz was one of few scientists who supported Einstein's search for general relativity from the beginning – he wrote several research papers and discussed with Einstein personally and by letter. For instance, he attempted to combine Einstein's formalism with Hamilton's principle,and to reformulate it in a coordinate-free way. Lorentz wrote in 1919:
Quantum mechanics
Lorentz gave a series of lectures in the fall of 1926 at Cornell University on the new quantum mechanics; in these he presented Erwin Schrödinger's wave mechanics.Civil work
After World War I, Lorentz was one of the driving forces behind the founding of the Wetenschappelijke Commissie van Advies en Onderzoek in het Belang van Volkswelvaart en Weerbaarheid, a committee which was to harness the scientific potential united in the Royal Netherlands Academy of Arts and Sciences for solving civil problems such as food shortage which had resulted from the war. Lorentz was appointed chair of the committee. However, despite the best efforts of many of the participants the committee would harvest little success. The only exception being that it ultimately resulted in the founding of TNO, the Netherlands Organisation for Applied Scientific Research.Lorentz was also asked by the Dutch government to chair a committee to calculate some of the effects of the proposed Afsluitdijk flood control dam on water levels in the Waddenzee. Hydraulic engineering was mainly an empirical science at that time, but the disturbance of the tidal flow caused by the Afsluitdijk was so unprecedented that the empirical rules could not be trusted. Originally, Lorentz was only supposed to have a coordinating role in the committee, but it quickly became apparent that Lorentz was the only physicist to have any fundamental traction on the problem. In the period 1918 till 1926, Lorentz invested a large portion of his time in the problem. Lorentz proposed to start from the basic hydrodynamic equations of motion and solve the problem numerically. This was feasible for a "human computer", because of the quasi-one-dimensional nature of the water flow in the Waddenzee. The Afsluitdijk was completed in 1932, and the predictions of Lorentz and his committee turned out to be remarkably accurate. One of the two sets of locks in the Afsluitdijk was named after him.
Family
In 1881, Lorentz married Aletta Catharina Kaiser, with whom he had two daughters and one son. The eldest daughter, Geertruida, was a physicist and a doctoral student of her father. She married Wander de Haas, who was the Director of the Kamerlingh Onnes Laboratory at Leiden University.Death and funeral
In January 1928, Lorentz became seriously ill, and died shortly after on 4 February. The respect in which he was held in the Netherlands is apparent from Owen Richardson's description of his funeral:Unique 1928 film footage of the funeral procession with a lead carriage followed by ten mourners, followed by a carriage with the coffin, followed in turn by at least four more carriages, passing by a crowd at the Grote Markt, Haarlem, from the Zijlstraat to the Smedestraat, and then back again through the Grote Houtstraat towards the Barteljorisstraat, on the way to the "Algemene Begraafplaats" at the Kleverlaan, has been digitized on YouTube. Amongst others, the funeral was attended by Albert Einstein and Marie Curie.
Tributes
According to his biography published by the Nobel Foundation, "It may well be said that Lorentz was regarded by all theoretical physicists as the world's leading spirit, who completed what was left unfinished by his predecessors and prepared the ground for the fruitful reception of the new ideas based on the quantum theory."Lorentz is considered one of the prime representatives of the "Second Dutch Golden Age," a period of several decades surrounding 1900 in which the natural sciences flourished in the Netherlands.
Richardson describes Lorentz as:
A man of remarkable intellectual powers. Although steeped in his own investigation of the moment, he always seemed to have in his immediate grasp its ramifications into every corner of the universe. The singular clearness of his writings provides a striking reflection of his wonderful powers in this respect. He possessed and successfully employed the mental vivacity which is necessary to follow the interplay of discussion, the insight which is required to extract those statements which illuminate the real difficulties, and the wisdom to lead the discussion among fruitful channels, and he did this so skillfully that the process was hardly perceptible.
M. J. Klein wrote of Lorentz's reputation in the 1920s:
For many years physicists had always been eager "to hear what Lorentz will say about it" when a new theory was advanced, and, even at seventy-two, he did not disappoint them.
Einstein wrote of Lorentz:
Poincaré said of Lorentz's theory of electrodynamics:
Paul Langevin said of Lorentz:
Lorentz was chairman of the first Solvay Conference held in Brussels in the autumn of 1911. Shortly after the conference, Poincaré wrote an essay on quantum physics which gives an indication of Lorentz's status at the time:
Publications
- Many papers by Lorentz are available for online viewing .
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