Arie Bijl, theoretical physicist turned resistance fighter
He corresponded with Albert Einstein, worked with Nobel laureate Jan Tinbergen and was mentored by theoretical physicist Paul Ehrenfest. The Dutch resistance fighter Arie Bijl was in the highest echelons of his field at Leiden University before his death in Neuengamme concentration camp.
“Thanks in part to Arie Bijl's theory, we understand how helium is liquefied,” says Leiden professor of physics Sense-Jan van der Molen. Bijl described the theory for several experiments in Heike Kamerlingh Onnes' lab in the 1920s and 1930s. For example, Bijl studied how boson particles could be brought closer together to form a liquid. Bijl, toward the beginning of World War II, also developed a function describing the behavior of such particles. “This function is still used today. The American and Nobel laureate Richard Feynman refined it into the Bijl-Feynman formula in 1954.”
Arie Bijl was born in Maassluis in 1908 and soon the family realized that both Arie and his brother Jaap were such bright minds that they had to study in Leiden. The family settled down in Oegstgeest. Arie's father started a textile store on Kempenaerstraat, while the older siblings helped pay for Arie and Jaap's study expenses.
In Leiden, Arie came into contact with Kamerlingh Onnes and other Leiden academic luminaries, was part of economist Jan Tinbergen's discussion club on unemployment and himself received his doctorate in physics in 1938. (Here is the thesis and here is the laudatio said at the defense by his advisor H.A. Kramers.)
Leiden University was shut down in 1940, shortly after the German invasion. Teaching stopped, but research in the laboratory continued. Arie arranged hiding addresses for his Jewish colleagues and friends. In this, the family's textile store proved to be the hub of the web. “The store exchanged hiders”. “A customer would come and say, 'I bought a skirt, but I still prefer those pants.' Then a girl had to be exchanged for a boy.” The store was owned by the family until 2008.
Arie married Agnes Beket in January of 1944 and a few months later was arrested by the German occupation. A fellow resistance fighter had been arrested on the train, carrying a fateful list full of names. Arie was taken in October to the Neuengamme concentration camp near Hamburg where he died of maltreatment on 2 January 1945. He never knew his son Maarten, who was born after his deportation.
Source: Leidsch Dagblad (2022).
Arie Bijl (center) with colleagues Van Ierland (left) and Taconis (right). Photograph from 1944. According to this report, Bijl was in charge of a division that prepared the low-temperature charts for the Bureau International du Froid.
Commemorative stone (Stolperstein) in front of the house where Arie Bijl lived after his marriage (Emmalaan 32 in Oegstgeest). The current director of the Leiden physics department, Sense-Jan van der Molen, pays tribute.
