Superfluid 3He Surface bound excitations and A-B interface dynamics

Non-Technical Abstract

The devices we use every day have enriched our lives immeasurably and are often cheaper and faster than the best available a generation ago. Many of these advances have relied on progress in condensed matter research that has ultimately contributed to the economic well-being of the Nation. This project will demonstrate a significant advance in the measurement of frequency – actualizing a precise clock, with an accuracy approaching that of the Global Positioning System (GPS).

The research aims to identify exotic material behaviors or exotic magnetic behaviors that could, in the future, could form the basis of new types of devices for metrology and computation. The research team will accomplish this by designing and fabricating structures that will access new areas of quantum nano-fluidics and enable precision measurements on helium films down a few atoms thick.

These films will be contained in specially fabricated silicon nanostructures, under conditions where new phases should emerge that have exotic behaviors such as chirality (where the fluid exhibits a handedness like the spin of a top), or exotic magnetic behaviors, quantized flow or highly conducting “edge states”. The conversion from one state to another (“phase transition”) should reveal whether models of the early universe (important for our understanding of the evolution of the universe) can be tested in the laboratory.

Our past graduate students and undergraduates have gone on to productive careers in academia, high-technology industries and the financial sector, and the planned research will prepare a new generation of students for challenging careers. Throughout their tenure, our graduate and undergraduate students will present their findings to both technically advanced and lay audiences to encourage broader participation of junior and high school students in the STEM fields.

Technical Abstract

Superfluid 3He can inform research activity that extends across many fields in Physics. The project combines nanofluidics (examining fluid behavior confined within silicon cavities with sizes tuned to the scale of the superfluid’s coherence length), high-precision low-noise thermometry with low temperature physics, to expose new size effects. It will require the development of new measurement protocols to utilize low noise capabilities of SQUIDs and enable high precision measurement of frequency (and thus assay mass of ultra-thin films).

The experimental activity will probe excitations in these thin films or bound near surfaces using transport (superfluid density and heat conductivity). It is predicted that entirely new superfluid states can be stabilized by such confinement. Confinement and new high precision techniques will also provide the means to study the surface/edge excitations.

Furthermore, this research activity will provide a new example of "cosmology in the laboratory" where a transition from one superfluid state to another under confinement should proceed only by “intrinsic mechanisms”. The occurrence of such transitions will potentially provide a model of processes during the inflationary epoch of the early universe.

New geometries will explore the physics of quantum transport across single and multiple interfaces. Eventually, the new superfluids that emerge under confinement might be of interest in quantum computation. By combining low temperatures, nano fabrication, and high precision measurements, graduate students and undergraduates will be exposed to the exciting training ground that has prepared scientists for leading roles in academia and high-technology industries.

Personnel will also work to hone communication skills and enable diverse participation into the STEM fields.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.