By invitation only

The Hôtel Métropole in Brussels is a legendary conference venue that will ring a bell to all physicists. 100 years after the first meeting of the Conseil de Physique Solvay, a representative group of the world’s most eminent physicists met again in October this year in the Excelsior Room to discuss “The Theory of the Quantum World”. Three members of CERN's Theory Group were invited to participate. Gian Giudice, one of them, shares with us his thoughts and impressions about this exclusive conference.

Attendees at the 25th Solvay Conference on Physics, Brussels. Photo provided by "International Solvay Institutes".

“In the tradition of the Solvay Conferences, this is a discussion-oriented meeting with few talks by rapporteurs.” Thus reads the Introduction to the Scientific Programme of the Solvay Conference on Physics. In the Conference programme, the rapporteurs speak for only 30 minutes, with the specific aim of triggering discussion with the audience. And, if you scroll down the list of the rapporteurs, you will find names that have written or are in the process of writing the history of physics. Most of them are Nobel Laureates.

Gian Giudice, Ignatios Antoniadis and Gia Dvali, all members of the CERN Theory Group, and Gabriele Veneziano, a former CERN staff member, were invited to participate. Gian Giudice was also invited to give a five-minute introduction about “What we learned from Higgs searches at the LHC”. “The intense discussions among the participants are the strong point of this unique conference,” says Gian Giudice. “The number of participants is only about three times greater than it was 100 years ago at the first Conseil Solvay. If we think that the number of physicists involved in quantum physics has grown by a factor of at least a hundred, we can appreciate the pains that the organisers take to preserve the quality of the discussions.”

In 1911, the first Conseil Solvay brought together the finest physicists of the era, including: Marie Curie, Albert Einstein, Max Planck, Henri Poincaré and Ernest Rutherford. (Image Source.)

While quantum physics was in its early days 100 years ago, today it has become a sort of “umbrella” term comprising many different fields, from quantum gravity to quantum computation and quantum condensed matter. “The interdisciplinary nature of the conference is another important aspect,” observes Gian Giudice. “The discussions are between colleagues who are not necessarily involved in the same type of research. This always makes the exchanges very enriching. The field of quantum physics has changed dramatically over the last 100 years, but the lively way in which theoretical physicists argue and discuss has remained the same.”

Indeed, one of the enriching discussions this year directly concerned an issue with a CERN stamp: the Bell inequalities. “John Bell was a CERN staff member. His work on the quantum entanglement has significantly contributed to our deep understanding of the quantum world,” says Ignatios Antoniadis, Head of the Theory Group.

The enlargement of the scientific field is not the only difference Gian observes when comparing the first Conseil Solvay with the 25th such event that was held this year. “100 years ago quantum physics was essentially a European affair, but today it is completely international. The largest number of participants this year came from the US, but there were also eminent physicists from India, for example,” he says.

Although the field has widened its borders, not much has changed in the gender ratio. “At the first Conseil Solvay the only woman was Marie Curie. This year, although the total number of participants was about three times higher, there were only two women among us,” confirms Gian Giudice, who then adds: “Theoretical physics is still dominated by men. Hopefully something will change in the future.” The case has been made…

by Antonella Del Rosso