About Us
Our group's research interests are in the following areas:
- Visualization study of quantum turbulence in superfluid helium-4 using laser-induced fluorescence techniques
- Helium-based dark matter detector research and development
Turbulence, as Nobel Laureate Richard Feynman described, is "the most important unsolved problem of classical physics". The lack of a general solution to the governing Navier-Stokes equations means that there is no fundamental theory of turbulence. Surprisingly, turbulence is also possible in a pure superfluid in spite of the fact that flow of the superfluid must be irrotational and inviscid. This is because rotational motion in a superfluid becomes possible in the presence of the topological defects called quantized vortex lines. Unlike the random vortices in a classical fluid, in superfluid He-4 the vortices are identical in the sense that they all have a single quantum of circulation. Quantum turbulence is a tangle of these quantized vortices. At finite temperatures, due to its two-fluid nature, superfluid helium possesses peculiar new turbulent dynamics that is new to physics. At the mean while, superfluid helium is an important cryogenic coolant for engineering applications. Heat transportation in helium however can be strongly affected by the presence of turbulence. Studying turbulence in superfluid helium thus not only will enrich our knowledge of turbulence in general but also has practical significance. [See details]
We also work on helium-based dark matter detector research and developement. The discovery of nonbaryonic dark matter is one of the most intriguing story of modern astrophysics. Standard cosmological models predict that about 28% of the total-mass energy content of the universe is matter, and of that, roughly 20% is observable (baryonic) matter; the remaining 80% is non-baryonic, or so-called "dark matter". While evident on multiple astronomical length scales through its gravitational effects, dark matter has an unknown intrinsic nature. The possibility that dark matter particles are relatively light (mass <20 GeV) has recently garnered significant attention. Direct searches for light dark matter particles are especially challenging because of the low energies transferred in elastic scattering, resulting in few events above energy threshold for the heavy nuclear targets typically used in dark matter experiments. Helium-4 nucleus are kinematic matched to light dark matter particles. Using superfluid helium-4 as a target material shall allow us to explore the low-mass regime of the dark matter parameter space that other detectors can hardly access. [See details]
News and Announcements
- We look for passionate and dedicated students to join our lab. Interested candidates are welcomed to send inquires to Dr. Wei Guo.
