26869196
Mean-field theory of the Potts glass.
Etude du gel de spins de Potts, a l'etat p et avec interaction aleatoire, en une phase verre de Potts, ou la symetrie de Potts n'est pas brisee en moyenne. Differences avec les verres de spin: les deux phases verre de Potts se distinguent par la nature des correlations entre les divers etats fondamentaux degeneres du systeme
170218458
The discovery of asymptotic freedom and the emergence of QCD
T he progress of science is much more muddled than is depicted in most history books. This is especially true of theoretical physics, partly because history is written by the victorious. Consequently, historians of science often ignore the many alternate paths that people wandered down, the many false clues they followed, the many misconceptions they had. These alternate points of view are less clearly developed than the final theories, harder to understand and easier to forget, especially as these are viewed years later, when it all really does make sense. Thus, reading history one rarely gets the feeling of the true nature of scientific development, in which the element of farce is as great as the element of triumph.

The emergence of QCD is a wonderful example of the evolution from farce to triumph. During a very short period, a transition occurred from experimental discovery and theoretical confusion to theoretical triumph and experimental confirmation. In this Nobel lecture, I shall describe the turn of events that led to the discovery of asymptotic freedom, which in turn led to the formulation of QCD, the final element of the remarkably comprehensive theory of elementary particle physics—the Standard Model. I shall then briefly describe the experimental tests of the theory and the implications of asymptotic freedom.

The early 1960s, when I started my graduate studies at UC Berkeley, were a period of experimental supremacy and theoretical impotence. The construction and utilization of major accelerators were proceeding at full steam. Experimental discoveries and surprises appeared every few months. There was hardly any theory to speak of. The emphasis was on phenomenology, and there were only small islands of theoretical advances here and there. Field theory was in disgrace; S-Matrix theory was in full bloom. Symmetries were all of the rage. Of the four forces …
121273546
A Mechanism for Quark Confinement
I shall describe in this lecture a new approach to the dynamics of quarks. It is widely believed that the strong interactions are described by QCD, a nonabelian (SU(3)) gauge theory of colored quarks and gluons, permanently confined in color singlet hadronic bound states. Our knowledge of the nature of the constituents of hadrons derives from their observed symmetries, the success of various phenomenological models such as the quark model and most important from the observed short distance behavior of hadronic currents. It is this free-field theory behavior at large momentum (asymptotic freedom) that singles out nonabelian gauge interactions as the source of the strong interactions, allows us to directly observe the quantum numbers of the quarks and to derive quantative predictions that can test the validity of the theory.
124543277
Are instantons found
It is argued that the recent prediction of the a dependence of the coupling, g (a), of an effective lattice gauge theory for quarkless qauntum chromodynamics is confirmed by a recent numerical evaluation of g (a) for a latticized SU(2) gauge theory, thus providing strong evidence for the dynamical role of instantons. Additional predictions, testing the validity of the quantum chromodynamics bag model, are presented.
120775506
Density of states in the presence of a strong magnetic field and random impurities
Abstract A supersymmetric formalism is used to rederive a recent beautiful result of Wegner concerning the density of state of an electron gas in the presence of a strong magnetic field and impurities. The derivation is simple and applicable to any (local) distribution of scatterers. Explicit formulae are given in two dimensions. A Poisson distribution of scatterers leads to an interesting condensation phenomenon when the magnetic field is increased.
36890636
The Triumph and limitations of quantum field theory
Talk presented at the conference ``Historical and Philosophical Reflections on the Foundations of Quantum Field Theory,'' at Boston University, March 1996. It will be published in the proceedings of this conference.
38998939
Decoupling confinement and chiral-symmetry breaking: An explicit model.
Using a covariant model of mesons developed previously, we obtain new numerical solutions for the light-quark sector, and show explicitly how the small mass of the pion emerges as a natural consequence of chiral-symmetry breaking. Then we generalize the model, and show how chiral-symmetry breaking and confinement could be realized through completely independent mechanisms with different mass scales. In particular, the confining potential can be chosen to be purely scalar, as suggested by lattice studies and phenomenology, and the remaining part of the interaction can be chosen to be chirally invariant. In a symmetry-breaking mode, this new model can still generate quark mass and a massless-pion bound state.