Jerzy “Jurek” Lewandowski, born September 15, 1959, passed away in Warsaw, Poland, on October 8, 2024 at the age of 65. With over 200 influential manuscripts, he was regarded as one of the main pioneers of the loop quantum gravity approach to quantum gravity and an important expert on general relativity. He held the chair formerly occupied by Leopold Infeld and Andrzej Trautman at the University of Warsaw, highlighting his standing as a towering figure in both classical and quantum aspects of gravitational physics in Poland.
Jurek’s PhD work explored geometric aspects of gauge theories and various features of the Cauchy-Riemann spaces. He completed his doctoral degree in 1989 with Andrzej Trautman on the “Applications of Cauchy Riemannian Geometry to the Study of Gravitational Fields”. Jurek then moved to Syracuse University as a postdoc on a Fulbright Fellowship to work with Abhay Ashtekar, where they started a long-term collaboration resulting in about 20 seminal papers of which four have more than 500 citations each. One of these papers — a status report on loop quantum gravity, written two decades ago — is still considered to be one of the most useful reference for students and experts in the field. At Syracuse, Jurek worked on several foundational papers on quantum Riemannian geometry underlying loop quantum gravity. These papers paved the path to many further developments, including precise definitions and detailed properties of the area and volume operators introduced independently by Carlo Rovelli and Lee Smolin, and eventually the Hamiltonian for the theory proposed by Thomas Thiemann. In addition, Jurek made key contributions to other areas of classical and quantum gravity. These include the development of the theory of quasilocal horizons that have by now largely supplanted event horizons, especially in numerical relativity; the Cauchy-Riemann structures and their relation to twistor theory; foundations of loop quantum cosmology; loop quantization of black hole spacetimes, and extensions of spin-foam models that provide a non-perturbative path integral approach to quantum gravity.
He was awarded the prestigious Humboldt Research Award by the Alexander von Humboldt Foundation, recognizing internationally leading researchers of their respective fields, which he used to enhance collaborations with the gravity group at the Friedrich-Alexander-University in Erlangen and with other groups in Germany. He also held a prestigious Visiting Research Professor position at the Institute for Gravitation and the Cosmos at Penn State for over two decades. Jurek was elected fellow of the International Society on General Relativity and Gravitation in 2016. He played a key role in the creation of the Polish Society on General Relativity and Gravitation and served as its founding president. He was also instrumental in bringing the triennial International Conference on Relativity and Gravitation GR20 and the 10th Edoardo Amaldi Conference on Gravitational Waves to Warsaw in 2013.
He was the mentor of a large number of undergraduate and graduate students and postdocs who have since become influential researchers in the field. With his heartfelt manner, his outstanding achievements, and his curiosity and openness to discussions, he was a great and inspiring figure, especially for young researchers. His humility and modesty touched many in the field. He was known to go an extra mile to help his students, postdocs and friends. He dealt with the indignities of being taller than most with grace. For example, he suffered in intercontinental travel, but nevertheless traveled extensively to forge connections and friendships with his colleagues all over the world.
An avid skier, he organized conferences and schools at ski resorts in Zakopane, Poland and Tux, Austria that inspired especially the younger researchers over decades. It was common to see him discuss physics passionately with participants late into the night after a day of lectures and skiing.
He is survived by his wife Elzbieta and his son Pawel. We will all miss his enthusiasm, energy, spirit of exploration and his characteristic sense of humor.
Abhay Ashtekar (PennState, Perimeter Institute), Kristina Giesel, Hanno Sahlmann (Friedrich-Alexander-Universitaet Erlangen-Nuernberg (FAU)), Carlo Rovelli (Aix Marseille U, Perimeter Institute, Santa Fe Institute), Jorge Pullin, and Parampreet Singh (LSU)