September, 1938  -  December, 2025

Birger was born in 1938 in Oslo, Norway to Benedicte Nicolaysen and Birger Martin Bergersen.  He passed away in December of 2025 in Vancouver.   He spent most of his childhood in Sweden due to the Second World War. He attended the University of Trondheim and completed a degree in engineering. After graduation he received a Wein Scholarship to study at Brandeis University, in Massachusetts. While studying there he met his wife Silvia in a beginner Russian Class. In 1964 after completing his Ph. D. Birger moved back to Norway where he held a fellow position with the Norwegian Science Foundation. Silvia travelled to Norway with him and they were married in Trondheim, Norway in 1966. In 1967 they moved to Gothenburg, Sweden where he was a Nordita Fellow at the University of Gothenburg and his daughter Eva was born. In the summer of 1969, the family moved to Canada and Birger was a postdoctoral fellow at McMaster University. Then in 1972 the family drove to Vancouver and Birger joined the Department of Physics at the University of British Columbia where he taught and did research until retirement in 2004.
His research and papers focused on steady state non-equilibrium phenomena using computer simulations combined with analytical methods such as renormalization group and mean field theories as the main tools. Birger also focused his research on interdisciplinary studies and his last project involved a critique of some standard economics models that he felt were based on a faulty understanding of thermodynamics and statistical mechanics. He co-authored with Michael Plischke (Simon Fraser University) a well-regarded advanced textbook in Equilibrium Statistical Physics that had three editions. The family cabin on the sunshine coast, was perfect for working on his chapters.
Birger had a genuine penchant for independent and creative scientific thought, and he passed this on to his many students, encouraging them to follow their interests and scientific passion. Birger had discussions with his students on life, current events, history and personal experiences and enjoyed taking them on hiking adventures in the local mountains. Birger had a strong desire to see as much as possible of the world and he was able to work with physicists in Australia, Singapore and Europe.
He was always interested in Nature and had been a mycologist since he was four years old, so in retirement he became an enthusiastic and active member of the Vancouver Mycological Society where he compiled the club’s many checklists of fungal species – including inventories from decades of fall mushroom shows – into a comprehensive database that he kept up-to-date for many years. The cabin he shared with Silvia on the Sunshine Coast was the base for many mushroom adventures.
He enjoyed attending music and theatre events and spending time with family and friends. He travelled with his family to Newfoundland, the Yukon and Haida Gwaii never saying no to an adventure and seeing parts of Canada. He was concerned about climate change and consumerism. He was always interested in hearing updates from past students (family, friends), on what they were working on and where they were living. He treated each day as a new adventure and embraced inquiry, exploration and art.
His kindness, curiosity and positive attitude and outlook on life have been valued by the many people he touched.

Birger will be greatly missed by his daughter Eva (James), Silvia, and grand daughter Laura. He is predeceased by his sister Kirsten (Neil Yocum).

A special thank you to the amazing staff at the Vancouver General Hospital, especially those in the Blackmore Pavillion, who provided professional care, support and compassion.