# Hendrik Lorentz

Hendrik Antoon Lorentz ( born July 18, 1853 in Arnhem, † February 4, 1928 in Haarlem ) was a Dutch mathematician and physicist. Lorentz laid the mathematical foundations on which the Special Theory of Relativity Albert Einstein has been established. Terms such as Lorentz force and Lorentz transformation were named after him. Due to the similarity of the name, he is often confused with the Danish physicist Ludvig Lorenz, after the example Lorenz gauge and Lorenz - Mie theory have been designated. The Lorenz attractor is named after the American meteorologist Edward N. Lorenz.

## Life

Hendrik Antoon Lorentz was born on July 18, 1853 as the son of Gerrit Frederik Lorentz and Geertruida van Ginkel in Arnhem. After his mother's death, his father married in 1862 Luberta Hupkes. Hendrik Antoon Lorentz was in 1870 at the University of Leiden, completed in 1871 his studies in mathematics and physics from, and returned to his hometown. There he found work as a teacher for evening classes at the high school, which he had visited. During this time he wrote his doctoral thesis on diffraction and refraction of light, and his doctorate in 1875 at the age of 22 years. He occupied in 1878, as professor of theoretical physics a set up for him chair at the University of Leiden, which he remained faithful throughout his life. 1899/1900, he served as rector of the university.

Between Lorentz and the Göttingen physicist Emil Wiechert was a year-long friendship. Lorentz Wiechert has several letters in the development of the principle of relativity explained and made an important contribution so that the history of Einstein 's theory. The correspondence between Lorentz and Wiechert was ex hist by Wilfried Schröder in Arch. Sci released in 1984.

Lorentz married Aletta Catharina Kaiser in 1881, whose father was Johann Wilhelm Kaiser ( 1813-1900 ) Professor at the Academy of Fine Arts and director of the Rijksmuseum in Amsterdam. They had two daughters and a son. His eldest daughter Dr. Geertruida Luberta Lorentz also studied physics and was married to migrant Johannes de Haas.

## Services

Hendrik Antoon Lorentz regarded as the leading figure in the theoretical physics of his time, who developed the electromagnetic theory of light and the electron theory of matter and also formulated a consistent theory of electricity, magnetism and light.

He studied at the beginning of his scientific creativity with the expansion of Maxwell's theory of electricity and light. So he has already resulted in his doctoral thesis new concepts, and his further work in this area revolutionized ideas about the nature of matter. In 1878 he published a study on the relationship between the speed of light and the density and composition of the passage medium.

One focus of Lorentz ' work was the movement of electrically charged particles. He postulated the concept of the electron as a carrier of electric charges and was able to explain the behavior of light as it passes through transparent bodies.

For the explanation of the Zeeman effect is the Lorentz and the Dutch physicist Pieter Zeeman split in 1902 the Nobel Prize for Physics in recognition " of the extraordinary services they have rendered by their studies on the influence of magnetism on the radiation phenomena " and their " pioneering work on the relationship between optical and electromagnetic phenomena. " Lorentz argued in the Nobel speech in the spirit of his ideas ether, which is why he introduction also notes the same:

"On the ponderable matter, I will have very little to say, but everything on the airwaves and electrons. - ( Free translation of the English original text. ) "

In 1908 he gave a plenary lecture at the International Congress of Mathematicians in Rome (Le partage de l' énergie et l' entre la matière ponderable éther ).

Lorentz was appointed in 1919 to head of the committee, which was to examine the effects of dyke-building on the water level in the planning of the Zuiderzee. His completed in the next eight years theoretical calculations were confirmed by decades of practice after the construction of dikes.

After Hendrik Antoon Lorentz, a lunar crater is named.

## Relativity theory

### From Lorentz to Einstein

As part of his electron theory Lorentz developed the concept of a completely stationary ether, which remained unaffected by the matter. In this model was the speed of light, regardless of the speed of the light source, as this was constant exclusively in relation to the ether. The latter would, however, mean that relative to the ether matter in motion towards the light or running away ( "ether wind "). However, this effect could be experimentally ascertained (eg the Michelson -Morley experiment). Therefore, Lorentz introduced in 1892 the adoption of a that moving matter is shortened in the ether ( using the same hypothesis was proposed in 1889 by George Francis FitzGerald ). The FitzGerald - Lorentz contraction hypothesis ( Lorentz contraction) was insufficient by itself, however, to explain all negative etheric wind experiments, so Lorentz in several papers (1892, 1895, 1899, 1904) developed the Lorentz transformation, whereby not only the length, but also the time coordinates were ( " local " ) depending on the position of the moving matter in the ether. This was for the time being a pure Lorentz auxiliary variable with no physical content, but Henri Poincaré showed in 1900 that the local time if and only occurs when moving observer synchronize their clocks with light signals in the ether. Poincaré was also the Lorentz's theory mathematically completed in 1905.

The Lorentz electrodynamics now formed the basis on which Albert Einstein special relativity could build. Einstein ( the work of Lorentz, but only until 1895 known ) removed the fundamental asymmetry in Lorentz's theory: what in one hand there were the stationary ether an "absolute " or preferred reference system, on the other hand talked all experiments for the validity of the principle of relativity, Lorentz's ether theory could only be compensated with auxiliary hypotheses. Einstein now realized that one must combine only the essential knowledge of Lorentz, namely the independence of the speed of light from the source, with the principle of relativity to construct a consistent electrodynamics of moving bodies. Einstein wrote in 1912:

"It is well known that the principle of relativity alone a theory of transformation laws of space and time can not be established. This depends known to the relativity of the terms " simultaneity " and " shape of moving bodies " together. To fill this gap, I led the HA Lorentz's theory of the stationary luminiferous ether borrowed principle of the constancy of the speed of light one that contains as well as the principle of relativity, a physical condition, which appeared justified by the relevant experiences (experiments of Fizeau, Rowland, etc.). "

Thus there was no room for a " resting" ether. In particular due to the realization that it is " true" time as opposed to " local time " is no, but each time in different inertial frames can be viewed as a time par excellence. That although the Lorentz ether theory and special relativity the Lorentz transformation have in common and thus experimentally can not be distinguished, the clear and transparent concept of Einstein's theory in the first years continued after 1905 compared to the interspersed with auxiliary hypotheses theory of Lorentz and Poincaré by. Nevertheless, the substantial benefits of Lorentz for the preparation of the theory of relativity are still appreciated, demonstrated by the fact that significant terms of the theory of relativity ( as Lorentz transformation, length contraction, Lorentz invariance, etc.) continues to bear his name.

### Position to the special theory of relativity

According to Einstein and Poincaré and Lorentz brought in 1906 (published 1909) his theory to a level on which it was experimentally equivalent in all respects to the theory of relativity. This Lorentz admitted that Einstein's principle of relativity was a great achievement with which many results of the theory can be easily achieved while Lorentz was able to win the same results only through complicated derivatives of the electromagnetic theory. Nevertheless Lorentz held fast to the idea of an absolute aether and an absolute simultaneity, claiming that the postulate of the constancy of light might possibly constitute too great a restriction on the research. But a sharp critique of the theory of relativity (except those carefully worded remarks ) was never practiced by Lorentz - because since its theory and relativity theory are experimentally indistinguishable, it was his opinion, mere " matter of taste ", to which of the two theories is committed. In his publications, he treated both views equally well, and showed a deep understanding of the kinematics of the theory of relativity. He demonstrated the consistency of the symmetry of the relativistic effects in lectures between 1910-12 ( published in 1929 ):

" The behavior of rods and clocks, their shortenings, or their slow issued at the time of the translational motion are superficial observation to a strange paradox occasion, which can be refuted but on closer inspection. "

For example, say that the standards of the other shorter two relatively moving observer. The assessment of the rod length based on the fact that the ends of the rods are measured simultaneously. If it is considered that the assessment of simultaneity in each system varies fails, and considering exactly where and when the measurements of the endpoints will be conducted in the respective system, falls, according to Lorentz away the contradiction. The same applies to the time dilation: if everyone is claiming that the clock of the other is slower, then the possible because always two synchronous, static clocks are needed to measure the dilation of a moving clock. However, due to the relativity of simultaneity can not be considered as synchronous clocks from the perspective of the other. Thus, both paradoxes can be easily dissolved in the sense of the theory of relativity and in other lectures ( held in 1913, published 1914), Lorentz was how to resolve this Paul Langevin (1911) and Max von Laue (1913 ), the so-called clock paradox ( twin paradox ) in front of him. He showed that to be moving away from the origin and then returns, compared to a backward clock is slow, and the perspectives of the moving clock using the Doppler effect could be shown a clock.

### Position to the general theory of relativity

In addition, Lorentz was one of the few that Einstein supported in its work to formulate a general theory of relativity. So Lorentz in 1915, published a paper in which he tried to present at this time Einstein " design theory" to connect to the Hamilton 's principle. And after Einstein had finally completed the general theory of relativity, Lorentz congratulated him, and published a series of papers (1916-1917), which contain important contributions to the further development of the theory. So Lorentz was the first to formulate the general theory of relativity was a coordinate -free, geometric way, which he, however, not fully succeeded.

Despite all Lorentz remained in his idea of a stationary ether, and said in a letter to Einstein, that such ether was perfectly compatible with the general theory of relativity. In his reply, Einstein explained that although one could describe the gravitational field of general relativity as ether but it was not dissimilar ether of classical physics, which possess a state of motion. Einstein attributed this further in some semi -popular works, such as for example a speech in 1920 in honor of Lorentz in Leiden. Since the term " ether" at Einstein only served as another term for the gravitational field of general relativity, this term could not prevail in modern physics.

### Lorentz and Einstein

Lorentz and Einstein harbored from the outset each other in great esteem, as can be seen not only from the published work, but also from their intense correspondence. So Lorentz paid tribute to the great achievements of Einstein and beat him in 1912 as a successor to his chair at the University of Leiden before. Conversely saw Einstein in Lorentz almost a fatherly figure. He wrote of Lorentz:

" 1909: I admire this man like no other, I want to say I love him. 1928: The enormous significance of his work lies in the fact that it forms the basis of the theory of atoms and the special and general theory of relativity. The special theory was a more detailed exposition of the ideas that are found in Lorentz ' research by 1895. 1954: That he did not do this step to special relativity theory was simply that it was psychologically impossible for him to renounce the reality of the ether as a material thing ( the carrier of the electromagnetic field ). Those who lived through this time, it understands. "

And Lorentz left no doubt that Einstein is the founder of the theory of relativity:

" 1914 ( letter to Einstein): I felt the need for a more general theory, which I tried to develop later and you formulated ( and to a lesser extent Poincaré ). 1928: I considered my time transformation only as a heuristic working hypothesis. The theory of relativity is therefore solely Einstein's work. And there can be no doubt that he would have found it, even if the work had been all his predecessors not done on the theory of this area. His work is independent of the previous theories in this sense. "

## Works

Many works of Lorentz are available at the Proceedings of the Royal Netherlands Academy of Arts and Science, Amsterdam.

- Lorentz, Hendrik Antoon: La Théorie électromagnétique de Maxwell et son application aux corps mouvants. In: Archives néerlandaises des sciences naturelles et exactes. 25, 1892a, pp. 363-552.

- Lorentz, Hendrik Antoon: The relative motion of the earth and the ether. In: Essays on Theoretical Physics. B.G. Teubner, Leipzig 1892/1907, pp. 443-447.

- Lorentz, Hendrik Antoon: Attempt of a Theory of Electrical and Optical Phenomena in Moving Bodies. E. J. Brill, Leiden 1895.

- Lorentz, Hendrik Antoon: About the apparent mass of the ions. In: Physical review. 2, No. 5, 1900, pp. 78-80.

- Lorentz, Hendrik Antoon: development of Maxwell 's theory. Electron theory .. In: Encyclopedia of mathematical sciences. 5, No. 2, 1904, pp. 145-288.

- Lorentz, Hendrik Antoon: Electromagnetic phenomena in a system moving with any, that of light -reach speed. In: Blumenthal, Otto & Sommerfeld, Arnold ( ed.): The principle of relativity. A collection of essays 1904/1913, pp. 6-26.

- Lorentz, Hendrik Antoon: The principle of relativity and its application to some particular physical phenomena. In: Blumenthal, Otto & Sommerfeld, Arnold ( ed.): The principle of relativity. A collection of essays. 1910/1913, pp. 74-89.

- Lorentz, Hendrik Antoon: The principle of relativity. Three lectures held in Teylers Foundation at Haarlem (1913). B.G. Teubner, Leipzig and Berlin, 1914.

- Lorentz, Hendrik Antoon: Mémoires de Deux sur la Physique Mathematique Henri Poincaré. In: Acta Mathematica. 38, 1915/1921, pp. 293-308. doi: 10.1007/BF02392073.
- Reproduction in Poincaré, Oeuvres tome XI, pp. 247-261.

- Lorentz, Hendrik Antoon: The theory of electrons. B.G. Teubner, Leipzig and Berlin, 1916.

- Lorentz, Hendrik Antoon: Conference on the Michelson - Morley experiment. In: The Astrophysical Journal. 68, 1928, pp. 345-351.

- Lorentz, Hendrik Antoon: The theory of relativity for uniform translations. In: . Lectures on theoretical physics at the University (1910-1912) Leiden, 4 Acad - Verl Ges, Leipzig 1929.