Joel L. Lebowitz, the George William Hill Professor of Mathematics and Physics at Rutgers, the State University of New Jersey, has made outstanding and lasting contributions in nearly all areas of statistical physics during a period of almost forty years.

Lebowitz's work on non-equilibrium statistical mechanics included foundational work concerning the adequate formalism for non-equilibrium statistical mechanics; work on specific models, e.g., for heat transport, for stationary flows, and for phase transitions in stationary non-equilibrium states; work on the derivation of Brownian motion, the Boltzmann equation and hydrodynamical equations from microscopic dynamics; the existence of dynamics in systems with infinitely many degrees of freedom; andmetastability and nucleation. His work on equilibrium statistical mechanics included deep rigorous results on the Ising model (uniqueness of equilibrium state, finiteness of correlation length in a field, exactly two equilibrium states in zero field below T_{c}, correlation inequalities including the so-called Lebowitz inequality, properties of and bounds on surface tension, roughening and wetting transitions.); existence of thermodynamics for non-relativistic matter composed of electrons and nuclei (with Lieb); work on the convergence of the virial expansion (with Penrose); work on the approach to mean-field theory in spin systems with long-range exchange couplings; work on disordered systems (with Griffiths); work on percolation and computer simulations of binary alloys.

Thanks to Joel Lebowitz, we all have an appreciation for what rigorous methods can do when pushed, especially on time-dependent phenomena, correlations, etc. By his example, his urging and his wide collaborations, an extraordinary range of work has been nucleated and moved forward, ranging from exact model solutions, through approximate equations of state, to pioneering Monte Carlo calculations for spinodal decomposition and polymer dynamics.

Finally, it is impossible to discuss Joel Lebowitz without mentioning his great services to the statistical physics community. His biannual Yeshiva and then Rutgers statistical physics meetings helped generations of statistical physicists calibrate their new ideas, particularly by observing Joel's reactions to their presentations. His editorial work, in the Journal of Statistical Physics, in the Domb-Lebowitz series on Phase Transitions and Critical Phenomena and in many other places, has also played an important role in bringing the field to its truly leading place in theoretical science. I would also like to mention Lebowitz's tireless work for human rights.

The Boltzmann Medal for 1992 is hereby awarded to Joel L. Lebowitz for his many important contributions to equilibrium and non-equilibrium statistical mechanics and for his leadership role in the statistical physics community.

Updated 18 June 1999.