The Search for Quantum Liquid Crystals

Abstract

Abstract We report our progress in the search fro quantum liquid crystals. By “quantum liquid crystals,” we mean quantum liquids which exhibit macroscopic orientational order but no (or incomoplete) spatial order. Such a system is necessarily composed of light molecules, so that even at very low temperatures the zero-point motion of the molecules keeps the system in the liquid state. The molecules must be sufficiently anisotropic and theinteractions sufficiently orientation-dependent to bring about macroscopic orientational order under appropriate conditions. Our goal is to occur. The most natural candidate is ortho-hydrogen. Despite the light mass of the molecules, the strong intermolecular attraction forces the system at low temperature into a crystal in free space. To prevent this from happening, we introduce an external field which makes it energetically advantageous to keep the molecules well apart, by means of an adsorbing substrate such as a graphite surface. At zero temperature and varying areal d...