Trajectories with my friends: Global phase diagrams plus high-temperature superconductivity and e-supermarket delivery optimization

I have been deeply thankful to my students and collaborators from day one of my academic career. For this special occasion, I would like to especially thank the Organizers of the ‘‘Friends and Trajectories’’ Symposium atMIT,Mehran, David, and Susan, and the Editors of this companion Volume, Joseph and Miron. I also thank all the attendees of the Symposium and the authors of the Volume, who have created such a singular memory. The setting for individual happiness and productivity is provided by highly diversified and accepting communities. My experience in such settings is my home town Istanbul, a world city that many of my international friends have explored with me (Fig. 1), and the statistical physics community. A city or a scientific field is only as good as the people in it and from this point of view I have been very lucky. I am therefore deeply grateful to my friends, colleagues, and students. I have started in statistical physics research 40 years ago andmy first dentwasmadewith the renormalization-group calculation of the global phase diagram of a multicritical system (Fig. 2). As many know, such calculations have remained a love of mine, but I have been also enjoying research in systems as diverse as supermarket food distribution optimization (Fig. 3) and high-temperature superconductor models (Fig. 4). In these forty years, I have listened to, interacted with, and collaborated with theorists and experimentalists; scientists and engineers; academicians and non-academicians; physicists, chemists, mathematicians, biologists, geologists, philosopher, . . . , in thisworld-spanning city that is statisticalmechanics. Our diversity and embrace of different backgrounds and methods is the dynamic of the never-ending vibrancy and astounding success of our field. It continues to be a great ride. I therefore thank again, with all my heart, my friends, colleagues, and students, three groups that are really one. A. Nihat Berker, Istanbul, February 2010