The Zieve lab works primarily in low-temperature experiment, but there are also some projects involving higher temperatures and computer simulations. The lab has a dilution refrigerator that can cool below 50 milliKelvin. A piezo-activated pressure cell can be mounted on the cryostat, enabling us to apply uniaxial stress to solid samples and change that stress at milliKelvin temperatures. Present work is on unconventional superconductors, particularly those with topological influences on their band structure.

Another main piece of low-temperature equipment is a pumped He-3 cryostat with a minimum temperature of 250 milliKelvin. We have used that for experiments on vortices in superfluid helium, but our present vortex experiment uses a home-built apparatus at a toasty 1.3 Kelvin. We levitate a bucket of helium, spin it, and watch the decay of its rotation. The experiment may serve as a useful model for the rotational behavior of neutron stars, where rotational glitches are believed to be caused by the superfluid interior of the stars. We hope to reproduce the glitch behavior and study how it changes with different parameters: rotation speed, rate of rotational damping, container size and shape, wall roughness, etc.

We have started preliminary measurements of bulk photovoltaics at room temperature. We will use our uniaxial pressure cells to explore how stress affects the photocurrent.

A separate experiment, designed to foster undergraduate involvement, is room-temperature work on granular piles. We have examined the effect of grain shape on pile density and stability; we are now trying to relate the precise grain configuration to a pile's stability.