The Message of Quantum Science II -How much have we learned in the past five years
Date: 6 - 10 November 2017
Convenors: Philippe Blanchard (Bielefeld, GER), Jürg Fröhlich (Zürich, SUI)
1. A Series of Events Devoted to Quantum Science
This workshop on the general subject of 'Quantum Science' has been No 3 in a series of events dedicated to surveys of recent progress in our understanding of Quantum Mechanics and its manifold applications and to debates on this subject among participants. The first event sailed under the title 'The Message of Quantum Science — Attempts Towards a Synthesis' and took place at the ZiF of Bielefeld University during the spring of 2012. It lasted several months and featured two workshops, attracting many colleagues from Central Europe and France. In the spring of 2015, a similar program, called Le Monde Quantique, was staged at the Institut des Hautes Études Scientiques (IHES) at Bures-sur-Yvette near Paris, with Jürg Fröhlich as the principal organizer, Thibault Damour and David Ruelle as co-organizers, and Philippe Blanchard as our guest of honor. This program, too, lasted several months. It started and ended with two high-level conferences. It was focused primarily on experimental progress in Quantum Science, featuring talks by all the famous experimentalists, including two Physics Nobel Prize winners, of the École Normale SupérieureUniversité de Paris Sud at Orsay and from Geneva who presented very stimulating lectures on recent experiments testing various subtle and puzzling properties of Quantum Mechanics, such as violations of the Bell inequalities, entanglement, decoherence ('Schrödinger cat states'), interactions between matter and the electromagnetic field, and the 'collapse of the wave function of a quantum system subject to repeated measurements. In contrast, the emphasis of the two events in Bielefeld was more on recent theoretical progress. We successfully tried to attract a fairly interdisciplinary crowd of mathematicians, theoretical physicists, experimental physicists and even some philosophers of physics as speakers and particpants to all three events.
2. Purpose and Focus of the Workshop at the ZiF in November 2017
The main purpose of this workshop was to find out how much progress has occurred in our theoretical understanding of Quantum Mechanics – from its foundations to novel applications – in the more than five years that have elapsed since the first event took place at the ZiF.
It is, to say the least, an awkward fact that the debate on the deeper meaning and interpretation of Quantum Mechanics has not come to a good end, yet. There is still a considerable amount of confusion among physicists – from students to full professors of theoretical physics – on what exactly Quantum Mechanics tells us about Nature. We feel that it is important to monitor progress towards dissolving this confusion, and this has been a key goal of our workshop. When Blanchard and Fröhlich were students work on the foundations of Quantum Mechanics was considered to represent a very unfashionable pursuit which only old people long after their scientific climax might engage in. It was argued that, after all, the Copenhagen interpretation of Quantum Mechanics and von Neumann's famous book had solved all or most of the problems befuddling the theory. Since then the opinion in the main stream of physics has changed radically?not least thanks to the advent of quantum information science and quantum computing, fields that force us to rethink the foundations which Quantum Mechanics is built upon.
At the ZiF workshop in November, many people lectured about novel ideas concerning the foundations of Quantum Mechanics – from Bohmian mechanics and Bell's ideas over Everett's 'many worlds' and other somewhat vague attempts towards understanding Quantum Mechanics all the way to the recently proposed 'ETH approach'. Other people talked about topics related to quantum information science and explained how quantum information theory may shed new light on fundamental aspects of Quantum Mechanics. In order to illustrate the very wide scope of Quantum Science, we invited some experts to talk about recent progress in quantum optics, the quantum mechanics of cold atoms and condensed matter physics, ranging from topological insulators to renormalization group methods applied to quantum many-body theory. These fields are of intrinsic interest; but they also play an important role in the construction of concrete devices for quantum information transmission and quantum computing.
The series of events organized by Blanchard and Fröhlich can be considered a big success. We believe that progress in our understanding of Quantum Mechanics has been made during the past five years and that it has been reviewed in a useful and thought-provoking way at the ZiF workshop in November 2017 (as well as at the two previous workshops). Most participants of the 2017 workshop have spontaneously assured us that they found the program of the workshop and the very lively discussions highly stimulating. One may hope that yet another workshop on Quantum Science will take place at the ZiF in five years from now, in order to review further progress and discuss solutions of problems that have not been understood satisfactorily, yet, or that will have come up during the coming years.
Michel Bauer (Gif-sur-Yvette, FRA), Ämin Baumeier (Wien, AUT), Jean Bricmont (Louvain-la-Neuve, BEL), Erwin Brüning (Durban, RSA), Detlev Buchholz (Göttingen, GER), Martin Carrier (Bielefeld, GER), Thibault Damour (Bures-sur-Yvette, FRA), André Deckert (München, GER), Jérémy Faupin (Metz, FRA), Nicolas Gisin (Genf, SUI), Sheldon Goldstein (Piscataway, USA), José Gracia Bondia (Zaragoza, ESP), Gian Michele Graf (Zürich, SUI), Philippe Grangier (Palaiseau, FRA), Mario Hellmich (Salzgitter, GER), Burkhard Kümmerer (Darmstadt, GER), Angela Lahee (Heidelberg, GER), Klaas Landsman (Nijmegen, NED), Vieri Mastropietro (Mailand, ITA), Peter Reimann (Bielefeld, GER), Helge Ritter (Bielefeld, GER), Andreas Ruschhaupt (Cork, IRL), Helmut Satz (Bielefeld, GER), Antoine Tilloy (Garching, GER), Piotr Ługiewicz (Breslau, POL), Reinhard F. Werner (Hannover, GER), Stefan Wolf (Lugano, SUI), Xiao Alvin Yang (Kassel, GER), Peter Zoller (Innsbruck, AUT)