Ludvig Valentin Lorenz ( ; 18 January 1829 – 9 June 1891)
was a
Danish physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
and mathematician. In 1867, he gave completely general integral solutions to the differential equations of electromagnetism, which contain retardation effects reflecting the finite speed of light. This paper also introduces the
Lorenz gauge, named after him.
Lorenz also developed mathematical formulae to describe phenomena such as the relation between the refraction of light and the density of a pure transparent substance, and the relation between a metal's electrical and thermal conductivity and temperature (
Wiedemann–Franz–Lorenz law).
His name is sometimes confused with that of the physicist
Hendrik Antoon Lorentz
Hendrik Antoon Lorentz ( ; ; 18 July 1853 – 4 February 1928) 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 ...
, who is incorrectly credited for
Lorenz's work.
Biography
Lorenz was born in
Helsingør
Helsingør ( , ; ), classically known in English as Elsinore ( ), is a coastal city in northeastern Denmark. Helsingør Municipality had a population of 63,953 on 1 January 2025, making it the 23rd most populated municipality in Denmark. Helsin ...
and studied at the
Technical University
An institute of technology (also referred to as technological university, technical university, university of technology, polytechnic university) is an institution of tertiary education that specializes in engineering, technology, applied science ...
in Copenhagen. He became professor at the Military Academy in Copenhagen 1876. From 1887, his research was funded by the
Carlsberg Foundation.
Work
Lorenz's greatest contribution (1867) is a development of general integral solutions to the differential equations of electromagnetism, which contain retardation effects reflecting the finite speed of light. This paper also introduces the Lorenz gauge, named after him. His 1867 paper can be regarded as contemporaneous with Maxwell's identification of light with electromagnetism waves (1865).
The Lorenz gauge hence contradicted Maxwell's original derivation of the EM wave equation by introducing a retardation effect to the Coulomb force and bringing it inside the EM wave equation alongside the time varying electric field, which was introduced in Lorenz's paper "On the identity of the vibrations of light with electrical currents". Lorenz's work was the first use of symmetry to simplify Maxwell's equations after Maxwell himself published his 1865 paper.
Lorenz also investigated the mathematical description for light propagation through a single homogeneous medium and described the passage of light between different media. The formula for the mathematical relationship between the refractive index and the density of a medium was published by Lorenz in 1869 and by
Hendrik Lorentz
Hendrik Antoon Lorentz ( ; ; 18 July 1853 – 4 February 1928) 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 derive ...
(who discovered it independently) in 1878 and is therefore called the
Lorentz–Lorenz equation or the Lorenz-Lorentz equation which preserves the historical order. Using his
electromagnetic
In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...
theory of light he stated what is known as the
Lorenz gauge condition
In electromagnetism, the Lorenz gauge condition or Lorenz gauge (after Ludvig Lorenz) is a partial gauge fixing of the electromagnetic vector potential by requiring \partial_\mu A^\mu = 0. The name is frequently confused with Hendrik Lorentz, who ...
, and was able to derive a correct value for the velocity of light. He also developed a theory of light scattering, publishing it in Danish in 1890 and in French in his Collected Works, published in 1898. It was later independently rediscovered by
Gustav Mie in 1908, so it is sometimes referred to as
Lorenz–Mie theory. Additionally, Lorenz laid the foundations for
ellipsometry
Ellipsometry is an optical technique for investigating the dielectric properties (complex refractive index or dielectric function) of thin films. Ellipsometry measures the change of polarization upon reflection or transmission and compares it ...
by using
Fresnel's theory of
refraction
In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commo ...
to discover that light reflected by a thin transition layer between two media becomes elliptically polarized.
References
Lorenz, L. (1867). "On the Identity of the Vibrations of Light with Electrical Currents". Philosophical Magazine. Series 4. 34 (230): 287–301.
External links
Scienceworld"Sur la lumière réfléchie et réfractée par une sphère transparente" pp. 405-529, Œuvres scientifiques de L. Lorenz, Volume 1"Modern Electrodynamics" pp. 789-790
{{DEFAULTSORT:Lorenz, Ludvig Valentin
1829 births
1891 deaths
People from Helsingør
19th-century Danish mathematicians
Danish physicists
Optical physicists