Quasi crystals- an overview

Abstract

This paper gives a broad overview of recent developments concerning quasi crystals. After briefly recapitulating various experimental facts, the architecture of quasi periodic systems in various dimensions is discussed. The various density-wave models are then reviewed. This is followed by a discussion of the extra long wavelength models which appear in such systems. Some comments are then made about possible relationship to recent theories of glass which stress local icosahedral order. The paper concludes with an outlook for the future.