100 years of new atom theory, celebrated in it’s homeland
How I visited the Neils Bohr Institute in Copenhagen
In the year that we celebrate the hundredth anniversary of atomic theory, which brought into being quantum mechanics, I had the chance to travel to the place where it all began — Copenhagen. When planning my trip there was one place I knew that I had to visit — the Niels Bohr Institute.
A little history — in 1913 Niels Bohr, a Danish physicist, published his revolutionary article “On the Constitution of Atoms and Molecules” (you can read the original text here).
Bohr was just 26 years old at the time, but he had already earned a doctorate from Copenhagen University, and also had the chance to work alongside the famous physicist Thomson in Cambridge, although their cooperation didn’t work out.
Thomson was a great scientist, but easily riled. The young scientist made a number of observations and pointed out some errors in the English professor’s previous calculations. Before long, Bohr moved on to Manchester to work with a new acquaintance, Rutherford. My readers will, I expect, know Rutherford for his planetary model of the atom, which is featured in school physics course.
It was at just this time, through his interaction first with Thompson and then with Rutherford that Bohr developed his atomic theory. Just three months after arriving in Manchester, when a student asked Rutherford to explain how the atom was built, the professor replied “Ask Bohr”.
In 1922 Bohr was awarded the Nobel Prize for Physics. Albert Einstein wrote about Bohr’s model that —
“It was as if the ground had been pulled out from underneath one’s feet, with no firm foundation left upon which to build a new one. That this insecure and contradictory foundation was sufficient to enable a man of Bohr’s unique instinct and tact to discover the major laws of the spectral lines and of the electron shells of the atoms together with their significance for chemistry appeared to me like a miracle and appears to me as a miracle even today. This is the highest form of musicality in the sphere of thought.”
The nobel-laureate’s fellow Danes literally praised him, while Bohr continued his theoretical calculations for many years after.
Bohr considered his biggest scientific achievement to be the correspondence principle, which became one of the foundations of modern science. Of course, his legacy though is much wider than that.
I became interested in Bohr some time ago because as well as being a great physicist, he was also a humanitarian and a philosopher. At the time of the rise of the Third Reich many academics in the name of science began working on atomic physics development and, in particular, a new type of weapon of mass destruction — the atom bomb.
Bohr, in order to save himself from the Nazis in the Second World War, was obliged to work with the American atomic projects. However, he maintained a categorical opposition to them, which he expressed to the country’s most important politicians, including President Roosevelt. He was particularly vocal after the attacks on Hiroshima and Nagasaki, and the rapid spread of nuclear testing that brought the technology right up to everyone’s “backyards”, even that of the USA.
In 1950 Bohr wrote an open letter to the UN expressing his concerns about the increasing speed of atomic militarization. As we know, it didn’t have much of an impact. Due to his friendship with Petr Kapitsa, Bohr was suspected of being a Soviet spy, and it was already too late to prevent the start of the Cold War. However, his position deserves respect.
Bohr was a uniquely gifted scientist and communicator. He devoted a lot of time to international cooperation in Physics, and was responsible establishing a society of scientists from many countries, including the USSR. One of his followers was Lev Landau.
When asked “how did you manage to bring together a group of brilliant, yet difficult people with such different temperaments, not least a new generation of physicists?” Bohr replied that he simply “wasn’t afraid to make a fool of himself in front of young people”.
There are three more reasons why I am interested in the history of physics. I’m a graduate of the Hydrometeorological University, where I studied the physics of the atmosphere in my first two years. Not long ago I had the chance to work in the R&D company connected to the Physics faculty at Moscow State University. My colleagues and managers were all physicists (except one biologist). At the moment I work for Runa Capital, a venture fund with close ties to the Moscow Institute of Physics and Technology, Phystech (Russia’s MIT) — Runa founders are MIPT graduates, and also co-founders of the Russian Quantum Centre and QWave Capital.
Incidentally, Eugene Polzik, who carried out pioneering research in quantum optics and communications, is, as well as being a member of the Russian Quantum Centre’s executive committee, also a professor at the Niels Bohr Institute, the director of the Danish centre for Quantum Optics and a member of the Danish Royal Academy of Science. However, I visited the Niels Bohr Institute as a tourist.
I have to say that I never imagined that the centenary of Bohr’s theory would be celebrated on such a large scale. The scientist’s portrait was all over Copenhagen and open lectures and events were held in the city’s museums and libraries. Of course, Denmark is not a big country, but all the same it was a very pleasant surprise to see such importance attached to a science-related event. Denmark’s national bank even released a special coin devoted to the theory.
The coin was introduced on the very same Monday that I paid my visit to quantum mechanic’s alma-mater.
The Niels Bohr Institute (NBI) is part of large Copenhagen University, and is state funded. The Institute’s scientists, alongside their research, teach undergraduates, set exams and work with phd candidates. The institute was founded by Niels Bohr himself in 1920, and he directed it until the end of his life.
On that centenary Monday I was able to enter the NBI without any problems — no authorization checks, no security. It seemed like I was going into to a student campus, and not a science establishment filled with super-intelligent people and hyper-expensive apparatus. On the walls there were posters about science-related events, fairs and exhibitions, and also announcing films about Bohr and his legacy.
After wandering around the campus for 20 minutes I decided it was time to meet someone working at the institute. When I appeared in reception they weren’t at all surprised, and at once called in an official guide — a nice old lady called Gerti. She seemed very pleased to see me.
My guide led me along corridors and up and down staircases and finally our first stop was Niels Bohr’s office. The room had classic simple furnishings — green wallpaper, brown furniture. On one of the walls, closer inspection revealed a collection of annual photos of all the institute’s staff. I spotted Bohr himself, who was there in all the photos up to 1962.
Gerti begun her story from Carlsberg, saying that Danish ‘‘beer-king’’ co-founder the Institute. Apparently the brewer was not only a successful businessman, but also a big science fan who donated a huge amount of money to researchers. He also loved to use scientific discoveries in his brewery, nowadays we would call him “innovative”.
Bohr achieved fame in Denmark as soon as his theory was first published and he started to defend it in debates.
He was then able to use his influence to make his institute a leading centre for theoretical physics research.
One famous resident of the Institute was the German physicist Werner Heisenberg. In the middle of the 20th century he and Bohr were responsible for bringing about a revolution in the world of physics. Through his discussions with Heisenberg, Bohr developed the complementarity principle, which dictates, aswell, that atoms can act as both particles and waves.
The complementarity principle has played a very important role in physics — Paoli was quite serious when he suggested that quantum mechanics should be called “the theory of complementarity”, in contrast to the theory of relativity.
In fact, Shredinger formulated his famous cat paradox in order to try and prove that Bohr’s “Copenhagen interpretation” was wrong. They argued the matter non-stop for several days at an “all physics stars” conference in 1926.
On the walls of Bohr’s office there were lots of photographs from his travels in China and the USSR. Gerti also explained that Bohr’s wife was utterly devoted to him, and wasn’t even offended that for their honeymoon he chose to take her to Manchester to meet Rutherford. They went on to have 6 children together.
Our next stop was a lecture theatre.
Largely thanks to Bohr’s reputation as the leading European radical, with lots of non-standard ideas, Copenhagen became a magnet for bright young physicists. Many of these enthusiasts gathered in this very lecture theatre dispute and refine this new branch of physics — quantum mechanics. Bohr himself designed a special blackboard for writing formulae — there were a cascade of boards that could be moved up and down so that he never had to break off his narration to wipe the board clean.
Bohr was also able to come up with new scientific ideas on the spur of the moment, but only when he had listeners. This made the lecture theatre an ideal place. Scientific gatherings here took place in an informal and cheerful atmosphere. For example, if Heisenberg didn’t like one of his colleague’s assumptions literally piped up, while other scientists loudly banged on the tables.
Date: 1930
Weisskopf, who studied under Bohr and went on to become a professor at MIT and a participant in the Manhattan project, wrote that
“It is impossible to imagine the sort of atmosphere, life, intellectual activity that we experienced in Copenhagen at that time. Bohr was always there, we saw him working, talking and living alongside young, happy, life-filled enthusiasts. They were coming to understand the deepest secrets about matter, possessed by an indescribable spirit of freedom, battle and joy.”
After we left the lecture theatre, Gerti led me on through the labs.
Moscow State University physicists once told me that a real scientist is one who can make any apparatus with his or her own hands — an engineer.
There are a number of fields of research at the Bohr Institute.
- Astronomy
- Geophysics and climate
- Particle physics
- Quantum physics
- Biophysics
- Condensed matter physics
- E-science as part of a project to build a grid for distributing calculations.
I was able to visit the labs in the Institute’s Quantum Physics complex, specifically — the Quantum optics department (QUANTOP).
The shelves were crammed with microchips and iron constructions, there were cables everywhere and somewhere in the depths of the space two young people were discussing something in broken English. I learned that they were Andy, from Germany and Louis, from France and I asked them to tell me about their work.
Andy explained that five groups of scientists work in QUANTOP, and that their goal is to create a photon source with the same properties as the one described in the EPR-paradox (named after Einstein, Podolski and Rosen). This would make it possible to simultaneously and precisely measure the coordinates and motion of particles, which in turn would allow them to combine the results of their experiment with those of parallel experiments investigating interaction between caesium atoms.
And with that, my tour of the Institute was over. Two hours had flown by. Gerti suggested that I leave a comment in the visitors’ book, and I gladly obliged, writing:
“I want to thank the institute, and Gerti in particular, for a wonderful excursion. I saw contemporary science, accessible to all. And also a contemporary scientific institution, which I hope to return to. Happy Birthday Niels Bohr!”
It was the 7th of October 2013.
