# Who is Paul Dirac?

June 26, 2021Paul Adrien Maurice Dirac, whose full name was Paul Adrien Maurice Dirac, lived from 8 August 1902 to 20 October 1984, was an English physicist and mathematician.

He is one of the founders of quantum mechanics. Among other important discoveries, he created the Dirac equation, which was named after him, which allowed the discovery of antimatter by explaining the behavior of fermions. Dirac shared the 1933 Nobel Prize in Physics with Erwin Schrödinger.

Paul Dirac was born and raised in the town of Bishopston, Bristol, England. His father, Charles Dirac, was an immigrant from the Swiss canton of Valais and earned his living as a French teacher. His mother was from Cornwall and was the daughter of a sailor. Paul had an older brother named Felix, who committed suicide in March 1925, and a sister named Beatrice. His childhood years were not very happy because of his father’s harsh and authoritarian attitude. He began his education at Bishop Road Elementary School, then continued at Merchant Venturers Technical College (later renamed Cotham Grammar School), where his father taught. Merchant Venturers’ was an affiliate of the University of Bristol, which mainly taught science and contemporary languages. This was interesting compared to the secondary schools in the UK at the time, which generally taught the classics, and Dirac would later explain that he was very grateful.

Dirac studied electrical engineering at the University of Bristol and graduated in 1921. Later, realizing that his main interest was mathematics, he completed his higher education in mathematics in Bristol in 1923 and received a scholarship to do research at St John’s College, Cambridge. He would spend most of his life here. While at Cambridge he became interested in general relativity and the nascent branch of quantum physics, which he became interested in in Bristol with the help of Ralph Fowler.

Dirac noticed similarities between the method of Poisson’s brackets used in classical mechanics and the matrix mechanics newly proposed by Werner Heisenberg for quantum mechanics. In his 1926 publication on this observation, Cambridge’s Ph.D. took the title.

In 1928, based on Wolfgang Pauli’s work on non-relativistic spin systems, he created the Dirac equation, a relativistic equation of motion for the electron’s wave function. This work led Dirac to predict the existence of the electron’s antiparticle, the positron. The positron was observed by Carl Anderson in 1932. Dirac’s equation also helped put the concept of spin into the framework of relativity. Thanks to this work, Dirac made history as the first person to use the term quantum electrodynamics and to establish this branch.

Dirac’s book The Principles of Quantum Mechanics (Oxford Science Publications, Oxford University Press), published in 1930, is a milestone in the history of science. It became the standard book for teaching the subject soon after it was published and is still in use today. In this book, Dirac gathered his work on Werner Heisenberg’s “Matrix Mechanics” and Erwin Schrödinger’s “Wave Mechanics” by associating measurable values with the operators acting on the Hilbert space of vectors describing the state of the physical system. He also used the notation called bracket notation, which would become universal later in the book, and the Dirac delta function for the first time.

In 1931, Dirac proved that the existence of a single magnetic monopole would explain the quantization of electric charge. Although this evidence has received a lot of attention, to date, no information has been obtained regarding the existence of a magnetic monopole.

In 1937 he married Eugene Wigner’s sister, Margit. He also adopted Margit’s two children, Judith and Gabriel. He also had two daughters, Mary Elizabeth and Florence Monica, with Margit.

Dirac held the honorary title of Lucasian Professor of Mathematics at Cambridge from 1932 to 1969. During the Second World War, he carried out theoretical and experimental studies on uranium enrichment using gas centrifuge. In 1937, Dirac developed his cosmological model based on the hypothesis of large numbers. Dirac said, “It bothers me a lot that we neglect infinities in the quantum theory, which we accept as a good theory. This doesn’t make sense. Logically, in mathematics you neglect a value because it is very small, not because it is infinitely large and we do not want it.” He was very dissatisfied with the renormalization approach used to deal with the infinities that emerged in quantum field theory, and his work on this topic began to fall more and more out of the mainstream. After moving to Florida to be close to his eldest daughter, Mary, Dirac spent the last ten years of his life at Florida State University in Tallahassee, Florida.

He remembers when one of his students, John Polkinghorne Dirac, was asked what his core belief was.

Prepared by: Sociologist Ömer YILDIRIM

Source: Omar