At the frontier of the quantum world

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 Serge Haroche on the occasion of the Nobel lecture in Stockholm, 2012. (Photo:

Serge Haroche on the occasion of the Nobel lecture in Stockholm, 2012. (Photo: Bengt Nyman / Flickr)

French Nobel laureate Serge Haroche will give the Paul Bernays Lectures next week at ETH Zurich. In his research he deals with the transition from quantum physics to classical physics.

He is one of the founding fathers of quantum technology. The experiments conducted by French Nobel laureate Serge Haroche 20 years ago paved the way for today’s quantum technological research - although scientists were interested in quantum mechanics long before this. At the beginning of the 20th century, researchers realised that the laws of classical physics were not able to explain the behaviour of individual atoms or light particles. Quantum physicists spent many years trying to describe these phenomena.

In the 1990s, Haroche was one of the first physicists to specifically study and control coupled quantum mechanical systems. "By doing so he showed that it was even possible to control such systems," says Klaus Ensslin, Professor of Experimental Physics at ETH Zurich and Director of the National Centre of Competence in Research Quantum Science and Technology ( NCCR QSIT ). Even though it’s still a giant step from controlling a quantum system to quantum technology, technology is ultimately nothing more than highly targeted control of a physical system customised to that technology."

Philosophy of the exact sciences


Next week Serge Haroche is invited by the Department of Humanities, Social and Political Sciences (D-GESS), the Department of Physics (D-PHYS) and the Department of Mathematics (D-MATH) at ETH Zurich to hold three lectures on his field of research. These will form this year’s Paul Bernays Lectures given in honour of the mathematician and philosopher who worked at ETH and died in 1977. The lecture series is dedicated to the philosophy of the exact sciences.

Serge Haroche’s research has focused primarily on the transition from the atomic world, in which the laws of quantum physics apply, to the world visible to the naked eye, which obeys the laws of classical physics. He is interested in the conditions that cause a system to cease functioning in a quantum physical manner and become classical. "The study of this transition and the attempt to bring both worlds together is key from a philosophical perspective. After all, there is only a single physical reality," says Norman Sieroka, physicist and lecturer in philosophy at ETH Zurich and member of the Paul Bernays Lectures’ advisory board. "We are happy that we could get Serge Heroche, an outstanding scientist who practises experimental quantum physics, to speak at this year’s Paul Bernays Lectures."

About Serge Haroche


Serge Haroche (70) is a professor of quantum physics at the Collège de France in Paris. In the 1990s, he managed to trap individual microwave particles (photons) by confining them to a space of only a few centimetres between two highly reflecting mirrors made out of a superconducting material. By using specially prepared atoms (so-called Rydberg atoms), he managed to change the quantum physical state of the trapped microwave photons. Finally - again with the help of Rydberg atoms, which he sent through the photon trap - he was able to measure this state without affecting the microwave photons. He succeeded in doing this even when the microwave photons overlapped between two different quantum physical states. He thus developed the experimental equivalent of Austrian physicist Erwin Schrödinger’s famous thought experiment in which a cat may be simultaneously alive and dead. For his research on the interaction between materials (atoms) and light (microwave photons), Haroche received the Nobel Prize in Physics in 2012 together with the American David Wineland.

Paul Bernays Lectures 2015


The Paul Bernays Lectures are an annual and three-part honorary lecture series dedicated to the philosophy of the exact sciences. They honour Paul Bernays, the logician, mathematician and philosopher of logic and mathematics, who taught and researched at ETH Zurich from 1933 to 1959. The Paul Bernays Lecture series invites outstanding speakers to present their pioneering research at ETH Zurich.

Tuesday 8 September 2015, 5:00 pm
Serge Haroche: How the laser has revolutionised physics over the last fifty years

Wednesday 9 September 2015, 4:30 pm
Serge Haroche: Controlling photons in a box and raising Schrödinger cats of light - when thought experiments become real

Wednesday 10 September 2015, 4:30 pm
Serge Haroche: Counting and controlling photons non-destructively

All lectures will be held in Auditorium F3 in the ETH’s main building, Rämistrasse 101, Zurich. The lectures will be given in English and are open to the public. Registration is not necessary.