Per Delsing

Professor Per Delsing was recently recognised for the experimental evidence of the dynamical Casimir effect, which means creating light from a vacuum. The Physics World journal ranked the breakthrough as number five in the world.
We were curious about the man behind the recognition and wanted to find out what prompted him to choose physics. We found him in the MC2 building at the Department of Microtechnology and Nanoscience. The view from his desk is fantastic. This is a man with a broad view of things.
Two events were important for Per Delsing's career choice.
Watching the moon landing on television with his family on 20 July 1969 was the first one.
The second one was the time he asked his father what superconductivity was.
"I might have been about twelve years old. I had heard the word and was stunned when he said he had no idea. Like most children, my brothers and I thought our father knew everything. I looked it up in Nordisk Familjebok."
He read that superconductivity was a quality in some materials that allows electric current to pass without resistance. An interest in the mysteries of physics was aroused in young Per.

Fascination for knowledge and technology 
His father was a lumberjack from Tärnaby in the interior of Norrland who was given the opportunity to climb the social ladder. He lost a finger during a work-related accident and used the compensation he received from worker's compensation to study engineering in Stockholm. While studying, a fascination for knowledge and technology was born that he subsequently passed on to his three sons – Per and his twin brother Lars-Olof and their two-year older brother Jerker. Their father organised quizzes for them in the evenings. The questions might pertain, for example, to geography and Swedish provinces or history and lists of monarchs.
"We were not unique. In Malmö in the 1960s and 1970s, lots of boys were nerdy in one way or another," he says.
Three brothers – three professors
The Delsing brothers had an easy time at school and continued their studies to higher education. All three of them became professors: Per in physics in Gothenburg, Jerker in electronics/data in Luleå and Lars-Olof in Nordic languages in Lund.

Per's interest in superconductivity has lasted for over forty years. He studied engineering physics in Lund and then did his diploma project on superconductivity at the prestigious ETH university in Zurich. He got his doctorate at Chalmers in 1990. His thesis concerned single electron tunnelling, and he still performs research and teaches in the subject.

  What can we use your research for?
"Most of it is basic research and aims to help us understand and explain nature. The next step might be for us or someone else to do something useful with the knowledge. I find it gratifying to utilize my knowledge and create something completely new!"
Per lives in Landvetter with Désirée, who is a language teacher. They have four daughters between the ages of 18 and 24. One of them is working on her master's degree in biotechnology at Chalmers.
Organising quizzes for his daughters was not an option when they were small.
"My mother did not work when we were small, which means that a lot was already finished when my father got home after work. My wife and I shared parental leave, and for a time we worked in shifts. Désirée went to work in the morning and came home at three in the afternoon, which is when I left for work."

Doctoral student with small children
This means that the years when Per's children were small unfortunately coincided with the period he was working on his thesis. They had three children during that period, and for a while he found it almost impossible to cope.
"I usually use this as an example for my doctoral students when they start to give up," he says covertly smiling.
This is what happened:
Per tried to construct a new type of circuit, which is known as a single electron transistor. He had not succeeded after four years.
"Times were tough both at home and at work back then. I considered doing something entirely different than pursing my doctorate. Then it occurred to me that maybe we should use aluminium instead of tin and lead. We tried this at the beginning of the fifth year, and aluminium resulted in more stable circuits that worked, and our results were positive."
Per and his wife are still married and will celebrate their 25th wedding anniversary soon.
ERC Advanced Grant from the European Research Council
The researchers working around Per Delsing can continue working for the next five years without financial concerns since he was awarded a large and prestigious Advanced grant from the European Research Council – ERC .
They will continue developing new quantum optics experiments. Per says that this enables them to ‘play with photons’, that is particles of light. Light is currently transmitted over anti-vibration optical tables, and the aim is to get photons to interact with atoms and with each other. The researchers now want to move the experiment to a chip and use light with lower frequency in the microwave domain.
"When light is pressed into a small area, we can integrate artificial atoms with photons and get them to interact more strongly."
Getting back to the moon landing that Per and his brothers watched with their father, he held onto the thoughts evoked by the experience over the years. When he was 30 years old and at the end of his doctoral studies, he was very close to submitting an application to the Swedish National Space Board. He never did so for various reasons.
What about the future?
He would like to continue performing research on superconductivity.
"When our youngest daughter moves away from home, it might be time to perform research abroad for a while, to do what wasn't possible when the children were small," concludes Professor Delsing.
Text: Marianne Lesslie
Published 30 May 2012

Published: Thu 23 Apr 2015.