Professor Jean-Pierre Hansen FRS of the University of Cambridge will be the first recipient of the new Liquid Matter Prize of the European Physical Society. This prize was created in 2002 by the EPS to honour outstanding achievements in this field of research. The prize will be awarded to Professor Hansen on the occasion of the 6th Liquid Matter Conference, to be held in Utrecht, July 1-6, 2005.

For more than one reason, it is fitting that Jean-Pierre Hansen should be the first recipient of this prize. During the past 40 years, a large and vibrant community of researchers in liquid-state physics has grown in Europe and the development of both this field and this community is closely linked to the career of Jean-Pierre Hansen. Jean-Pierre Hansen is a European scientist, par excellence . He was born in Luxemburg and studied physics in Belgium (Liège). For his subsequent scientific training he went to the Université de Paris-Sud (Orsay) where he obtained `Doctorat de Troisième Cycle' under the guidance of Bernard Jancovici and Dominique Levesque. He then became a student of Loup Verlet, one of the pioneers of computer simulation in Europe. Hansen's PhD thesis ("Contribution à l'Etude des Systèmes de Lennard-Jones classiques et quantiques") and the publications that resulted from it, have made a lasting impact. Chairman of his thesis examination committee was Jacques Yvon - one of the founders of theoretical liquid-state physics. After spending a year as a postdoctoral fellow in the US (Cornell), Hansen returned to France. In 1973, he was appointed professor at the Université Pierre et Marie Curie in Paris. In 1987 he was the founder and director of the Laboratoire de Physique of the new Ecole Normale Supérieure de Lyon.

Jean-Pierre Hansen has transformed liquid-matter research in Europe. First of all, because he has made major contributions to virtually all aspects of liquid-matter physics. But possibly even more important has been his role in shaping the field. When he started his scientific career, liquid-matter physics was lagging far behind other fields of science, mainly because of the lack of hard data that could be used to discriminate between different theories. In the 1960's, the Orsay "school" (Verlet, Hansen, Levesque and Weis) completely changed the approach to liquid-state theory by making use of computer "experiments" to test theoretical concepts. Computer experiments had been pioneered by Metropolis, Alder and Wood in the US. But, with the emergence of the "French school", the centre of gravity moved to Europe. The fact that there now exists an elegant and robust theory of liquid matter is in no small part due to the work of Hansen and collaborators.

Hansen is internationally recognized as an authority in the application of statistical mechanical methods to the prediction of the structure, phase behaviour, thermal and dynamical properties of liquid matter. He was the first to apply "exact" computer simulation methods to determine the complete phase diagram of a simple fluid. He proposed a successful and widely used freezing criterion based on the structure factor of liquids. His pioneering work on molten salts and dense plasmas has led the way to a quantitative understanding of the structure and dynamics of strongly correlated ionic liquids. But he also considered the properties quantum fluids, in particular in an astrophysical context. Later, Hansen's insightful molecular dynamics simulations of supercooled binary alloys provided the first quantitative tests of the mode-coupling theory of the kinetic glass transition. Aspects of this pioneering work are contained in the classic book that Jean-Pierre Hansen co-authored with Ian R. McDonald: "Theory of Simple Liquids" (1976). This book has already had two editions and, to this day, remains the key reference in the field.

From the early 1970's on, Orsay became the Mecca for scientists from all over the world who were interested in the combination of liquid-state physics and computer simulation. This was facilitated by the fact that, at that time, Orsay hosted the Centre Européen de Calcul Atomique et Moléculaire (CECAM) which offered hospitality (and computer time) to visiting scientists. Hansen was closely involved in CECAM activities and, in fact, not long after he moved to Lyon, CECAM followed him.

Hansen's charisma and unique international reputation were illustrated in a rather unexpected way when he organized the first EPS Liquid Matter Conference at the ENS in Lyon (1990). The number of attendants far exceeded all expectations, so much so that large tents had to be rented to host the parallel sessions. There can be little doubt that Hansen himself was the magnet that attracted this large audience. The scientific quality and unique atmosphere of this first meeting have convinced the Liquids community, both inside and outside Europe, to return to subsequent Liquid Matter conferences.