Lorentz

Described the Force on a Point Charge due to Electric and Magnetic Forces.

Introduction

Early Life and Education

In his youth, grade school did not only have school hours in the morning and afternoon, but also in the evening, when teaching was more free (resembling the Dalton method). In 1866, when the first high school (H.B.S.) at Arnhem opened, Hendrik Lorentz, a gifted pupil, was ready to be placed in the 3rd form. After the 5th form and a year of studying the classics, he entered the University of Leyden in 1870, obtained his B.Sc. degree in mathematics and physics in 1871, and returned to Arnhem in 1872 to become a night-school teacher, while preparing for his doctoral thesis on the reflection and refraction of light. In 1875, at the early age of 22, he obtained his doctorate, and only three years later, he was appointed to the Chair of Theoretical Physics at Leyden.

According to the 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.”

Contributions

Lorentz’s key contributions include:

• Lorentz Force: The Lorentz force is the combination of electric and magnetic force on a point charge due to electromagnetic fields. In physics, particularly electromagnetism, the Lorentz force is the combination of electric and magnetic force on a point charge due to electromagnetic fields. If a particle of charge q moves with velocity v in the presence of an electric field E and a magnetic field B, then it will experience a force: F = qE + qv × B
• Variations on this basic formula describe the magnetic force on a current-carrying wire (sometimes called Laplace force), the electromotive force in a wire loop moving through a magnetic field (an aspect of Faraday’s law of induction), and the force on a charged particle which might be traveling near the speed of light (relativistic form of the Lorentz force).
• Lorentz Transformations: Perhaps Lorentz’s most significant contribution was the derivation of the Lorentz transformation equations. These equations describe how space and time coordinates transform between observers moving at constant relative velocities. While developed within the context of the luminiferous aether theory, these transformations later became a fundamental component of Einstein’s special theory of relativity.
• Lorentz Invariance: An equivalence of observation or observational symmetry due to special relativity, implying that the laws of physics remain the same for all observers moving relative to one another within an inertial frame. It has also been described as “the feature of nature that says experimental results are independent of the orientation or the boost velocity of the laboratory through space.”
• Electromagnetic Theory: Lorentz expanded upon Maxwell’s electromagnetic theory, providing a more comprehensive explanation of the nature of light and its interaction with matter. He introduced the concept of the electron as a charged particle within atoms, which became a cornerstone of modern physics.
• Electron Theory: Lorentz developed the electron theory, which explained optical and electrical phenomena in terms of the behavior of electrons within materials. This theory provided a microscopic foundation for macroscopic electromagnetic phenomena.
• Zeeman Effect: Lorentz’s theoretical work on the interaction of light and magnetism predicted the splitting of spectral lines in a magnetic field. This phenomenon, known as the Zeeman effect, was experimentally discovered by his student Pieter Zeeman in 1896. Lorentz provided the theoretical explanation for this effect, which confirmed his electron theory and the connection between light and magnetism.

Quotes

Lorentz made several insightful observations, including:

• “Einstein has put an end to this isolation; it is now well established that gravitation affects not only matter, but also light.”
• “difform motion will in every case produce the same effects as gravitation.”
• “Everyone knows that a person may be sitting in any kind of a vehicle without noticing its progress, so long as the movement does not vary in direction or speed; in a car of a fast express train objects fall in just the same way as in a coach that is standing still. Only when we look at objects outside the train, or when the air can enter the car, do we notice indications of the motion.”
• “The Newtonian theory can no longer be regarded as absolutely correct in all cases;”
• “The whole Galileo-Newton system thus sank to the level of a first approximation, becoming progressively less exact as the velocities concerned approached that of light.”
• “Gravitation, ever since Newton, had remained isolated from other forces in nature; various attempts had been made to account for it, but without success. The immense unification effected by electro-magnetism apparently left gravitation out of its scope. It seemed that nature had presented a challenge to the physicists which none of them were able to meet.”
• “Time and space are not the vessel for the universe, but could not exist at all if there were no contents, namely, no sun, earth and other celestial bodies.”
• “Let there be in every material particle several material points charged with electricity, of which, however, only one be movable, and have the charge e and the mass μ.”
• “Briefly, everything occurs as if the Earth were at rest.”

Publications

Lorentz’s notable publications include:

The Theory of Electrons and Its Applications to the Phenomena of Light and Radiant Heat (1916)

“One has been led to the conception of electrons, i.e. of extremely small particles, charged with electricity, which are present in immense numbers in all ponderable bodies, and by whose distribution and motions we endeavor to explain all electric and optical phenomena that are not confined to the free ether. …according to our modern views, the electrons in a conducting body, or at least a certain part of them, are supposed to be in a free state, so that they can obey an electric force by which the positive particles are driven in one, and the negative electrons in the opposite direction. In the case of a non-conducting substance, on the contrary, we shall assume that the electrons are bound to certain positions of equilibrium. If, in a metallic wire, the electrons of one kind, say the negative ones, are travelling in one direction, and perhaps those of the opposite kind in the opposite direction, we have to do with a current of conduction, such as may lead to a state in which a body connected to one end of the wire has an excess of either positive or negative electrons. This excess, the charge of the body as a whole, will, in the state of equilibrium and if the body consists of a conducting substance, be found in a very thin layer at its surface.”

The Theory of Electrons and Its Applications to the Phenomena of Light and Radiant Heat (1916)

“Einstein’s theory has the very highest degree of æsthetic merit: every lover of the beautiful must wish it to be true…”

“…It is not necessary to give up entirely even the ether. …according to the Einstein theory, gravitation itself does not spread instantaneously, but with a velocity that at the first estimate may be compared with that of light…”

“…Einstein’s theory need not keep us from so doing; only the ideas about the ether must accord with it.”

Vision

Lorentz’s work laid the foundation for Einstein’s theory of special relativity and provided a deeper understanding of electromagnetism, space, and time.

Legacy

Lorentz shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect. He received many honors and distinctions during his life, including, from 1925 until his death, the role of Chairman of the exclusive International Committee on Intellectual Cooperation.

Lorentz’s work on the transformation equations was particularly significant. Although initially developed within the framework of classical physics, these equations were later adopted by Albert Einstein as a cornerstone of his special theory of relativity, revolutionizing our understanding of space, time, and the relationship between them.

Lorentz’s influence extended beyond his specific discoveries. He was highly respected by his peers and played a crucial role in fostering international scientific collaboration. As the Nobel Foundation stated, “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.” From 1925 until his death, he served as Chairman of the International Committee on Intellectual Cooperation.

Hendrik Lorentz’s contributions to physics were profound and far-reaching. He not only made groundbreaking discoveries but also provided the theoretical framework that paved the way for the development of relativity and quantum mechanics, shaping the course of 20th-century physics.