Preface

The Fourteenth Annual International Conference of the Los Alamos National Laboratory Center for Nonhnear Stu&es (CNLS), entitled "Quantum Complexity m Mesoscopic Systems," was held May 16-20, 1994 at the J Robert Oppenheimer Study Center at the Los Alamos National Laboratory.

The conference focused on systems having complex quantum and senuclassical behavior. The

meeting included aspects of the theory and experiment for these systems. The study of small

quantum systems has developed to the point that an exchange of ideas can lead to an active field of research with importance to Industry. The meeting was attended by the developers of the theory of sermclasslcal dynamics that allows for detailed calculations, and the creators of "band-gap" engineered materials that allow for novel experiments Theoretical topics included cycle expansions; semxclassical dynamics, and noise. Experimental systems included properties of nanometer scale devices; charge density wave materials; Josephson junction arrays, and atomic systems.

Mesoscoplc systems display a wide range of effects. Some of these effects have been clearly linked to the chaotic dynarmcs displayed by the structures, whereas others have been connected to the stochastic nature of the potentials in the system. The exact interplay between chaos and stochastlmty ~s still an active area of research. Many times a researcher in the field does not

approach the problem from the nonlinear science perspective, and the conference was meant to show that such an approach is both possible and fruitful. In the conference, we sought to present to the nonhnear scientist a sampling of the nonhnear phenomena and issues In mesoscoplc systems that might potentially define new areas of nonlinear research. We also sought to present to the device scientist developments in the science of nonhnear phenomena that might potentially impact their research

The science discussed at the conference is reflected in the papers in this proceedings volume. Experimental topics include hydrogen atom excitation by microwaves - long the example system for quantum chaos - and its solid-state analog in quantum well semaconductor microstructures,

the construction and measurement of "quantum corrals" using novel methods to arrange individual atoms on atomically flat metal surfaces, and the experimental reahzatlon of senuclasslcal "ballistic

transport of electrons in quantum anti-dot arrays The theory of nonhnear dynamical systems in- cluded transport in quantum dots, the superconductor-insulator transmon, and transport in systems where electron-electron Interactions are dominant These topics were approached in the traditions of condensed matter and in the modernities of nonlinear theory (such as the several articles on cycle expansmns)

The articles in these proceedings are representative of the exciting scientific presentations that marked the conference We hope the readers of these proceedings will be able to sense this excite- ment We thank the speakers and the presentors of papers in the poster session for their efforts and co-operation in the preparation of their manuscripts

We also thank the session chmrpersons - Predrag Cvltanovlc, Thierry Martin, Michael Roukes, Bala Sundaram, and Stuart Trugman - for their for encouraging discussion and sclenUfic exchange, and give special thanks to Robert Park for his banquet talk on "Funding m Science", and how

VII

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federal funds gets used (and misused)

We gratefully acknowledge the US Department of Energy, Office of Scientific Computing, for its essential support of the conference As usual, the CNLS adrmmstratlve staff, and m particular Barbara Rhodes, provided excellent organizational and secretarial support Finally, we are grateful to Los Alamos National Laboratory and its Director Slg Hecker for making available the Laboratory's excellent conference facdltles and organizational staff

Alan Bishop Robert Ecke

Ronme Mmmen