Current research interests center around the search for neutrinoless double-beta decay (0νββ) and the direct detection of dark matter.   The group has played a leading role in the construction, operation, detector upgrade, and data analysis of the EXO-200 experiment, which has produced one of the most sensitive searches for the 0νββ of 136Xe.  nEXO is a proposed tonne-scale experiment that aims to increase the experimental sensitivity to the 0νββ halflife by more than two orders of magnitude.  The UCSD group is leading an R&D program to develop low-noise, low-background cold readout electronics for nEXO.  The group is also exploring novel techniques to tag the 0νββ decay daughter nucleus 136Ba in situ, which can completely eliminate the radioactivity-induced background and make it possible to build a background-free experiment.