Superfluidity and Swallowtails; Hysteretic Behavior in Bose Condensates

We present a theory of hysteretic phenomena in Bose gases, using superfluidity in one dimensional rings and in optical lattices as primary examples. Through this study we are able to give a physical interpretation of swallowtail loops recently found by many authors in the mean-field energy structure of trapped atomic gases. These loops are a generic sign of hysteresis, and in the present context are an indication of superfluidity. We have also calculated the rate of decay of metastable current carrying states due to quantum fluctuations.Comment: 32 pages, 15 figures, REVTeX4; v2: added references, corrected fonts in figure

Artificial electromagnetism for neutral atoms: Escher staircase and Laughlin liquids

We show how lasers may create fields which couple to neutral atoms in the same way that the electromagnetic fields couple to charged particles. These fields are needed for using neutral atoms as an analog quantum computer for simulating the properties of many-body systems of charged particles. They allow for seemingly paradoxical geometries, such as a ring where atoms continuously reduce their potential energy while moving in a closed path. We propose neutral atom experiments which probe quantum Hall effects and the interplay between magnetic fields and periodic potentials.Comment: 4 pages, 1 color figure, RevTeX 4; v2 Revised introduction, additional reference

Rural Health Insurance and Competitive Markets: Not Always Compatible?

Health Insurance, Rural Health, Health Markets, Competition, Health Policy, Health Economics and Policy,

The Helios mechanical despin drive assembly for the high-gain antenna reflector

Helios is the German-American solar probe which comes within 0.31 Astronomical Units of the sun. A special thermal design and a dry lubrication system have resulted in successful operation up to now, with Helios having finished its first orbit around the sun

Interdisciplinary research concerning the nature and properties of ceramic materials

Interdisciplinary research on properties of ceramic materials with emphasis on refractory surface insulatio

Interdisciplinary research concerning the nature and properties of ceramic materials Semiannual status report, 16 Jun. - 15 Dec. 1969

Research status reports in ceramic materials including chemical, mechanical, atomic, and molecular propertie

Multidisciplinary research activity in the materials sciences with emphasis on ceramic materials Semiannual status report, Jun. 16 - Dec. 15, 1967

Effects of various energy environments on zirconium-oxygen-carbon system, solid state ceramics, surface properties, and ceramic materials processin