Quantum Mass Transport in Superfluid and Supersolid 4He

Cornell University, Ithaca NY

Investigators

Abstract

This project will develop device quality superfluid 4He Josephson junctions. These are for study of the superfluid Josephson effect in 4He and also to allow new devices such as the superfluid DC-SQUID to be operable near 2 Kelvin. Relatively high temperature quantum nanofluidic devices would have significant potential for practical applications, such as superfluid quantum interference gyroscopes for geophysics, geodesy, gravitation and climate change studies. A second component of this project will be a search for persistent currents in the putative 'supersolid' phase of 4He. This is the last 'super' phase of matter (besides BEC and superfluids) that can exist. A clear demonstration of the ability of the 4He solid to maintain a persistent mass current is required in order to be sure that the recently reported phenomena in that system are due to supersolidity. Integration of research and education via training of graduate students and post-docs is central to the project. For example, students trained in this program will learn and develop sub 10nm e-beam lithographic development of nanofluidic circuits These skills will be of wide utility, not only for quantum nanofluidic studies but also for new nanofluidic systems for biophysics and medicine. A sophisticated web site will be available as part of outreach activities: http://people.ccmr.cornell.edu/~jcdavis/. The 'Josephson Effect' is a macroscopic quantum phenomenon in which quantum effects can be measured by classical measurements such as mass transport. In this project we will develop superfluid 4He Josephson junctions. These will make new devices such as the superfluid quantum interference gyroscope, possible. Such devices have significant potential for practical applications such as for geophysics, geodesy, and climate change studies. In this project a search for persistent currents in a 'supersolid' phase of 4He will also be carried out. This is the last 'super' phase of matter. When a gas becomes dominated by macroscopic quantum physics it is known as Bose-Einstein condensate. In a liquid this situation is referred to as a 'superfluid' and for a crystalline solid it is called a 'supersolid'. This project will search for direct evidence that this supersolid phase is real.The integration of research and education via the training of graduate students and post-docs is central to the project. Two two students and a postdoc will pursue the research objectives learning, as they do, the techniques of nanofabrication, nanofluidics, cryogenics, ultra low temperature and ultra low noise engineering. A sophisticated web site will be developed and maintained as part of the project outreach activities: http://people.ccmr.cornell.edu/~jcdavis/.