Recent results on topology on the lattice (in memory of Pierre van Baal)

Abstract

Memorizing Pierre van Baal we will shortly review his life and his scientific achievements. Starting then with some basics in gauge field topology we mainly will discuss recent efforts in determining the topological susceptibility in lattice QCD. Pierre van Baal (Naarden, June 9, 1955 - Leiden, December 29, 2013) was a great theoretician many members of the lattice field theory community remember very well. He passed away much too early. He was not a 'latticist' by himself, but strongly interested in what one can learn from lattice theory about fundamental aspects of non-Abelian gauge theories like gluon and quark confinement. There are several colleagues who were inspired by his ideas and approaches. The author of this contribution and some of his coauthors are grateful to belong to them. Pierre started his career with the B.Sc. in Physics and Mathematics in Utrecht. Having received his M.Sc. in 1980 he continued with the Ph.D. in Theoretical Physics at Utrecht University, where his advisor was Gerard 't Hooft. After that in 1984 he moved to Stony Brook first as a Research Associate and then as a Fellow in the joint Math/Phys Program. From 1987 to 1989 he became a Fellow at the CERN Theory Group. In 1989 he was appointed KNAW-Fellow by the Royal Academy of Sciences at University of Utrecht, before he became a full professor in Field Theory and Particle Physics at Instituut-Lorentz for Theoretical Physics of the University of Leiden in 1992. There he was not only a very motivated researcher but also an engaged teacher, even with projects for school kids. We all liked him as a very nice, modest person and a good friend of many of us. Having been attacked by a serious stroke just after returning from LATTICE '05 in Dublin, he found strong forces to recover and to reestablish his ability to talk, to travel and even to give lectures. Unfortunately and tragically, his hope and efforts to come back to research work - as he liked it so much - failed. But now we feel how much we all miss him.