I am a theoretical cosmologist by training but much of my recent work has been focused on how to extract fundamental properties of our universe from cosmological observations. The so called standard cosmological model of the universe has been very successful in explaining most of the cosmological observations to date. In this model the universe begins with a Big Bang followed by inflation during which the universe becomes nearly flat and the initial structures are seeded through quantum fluctuations. After its decay the universe is filled with radiation and matter, of which dark matter is itsmain component. Another component dubbed dark energy is needed to explain its acceleration in recent times and if it is in the form of cosmological constant it will dominate the expansion of the universe forever into the future. Despite the success of this model there is no shortage of theoretical alternatives, some of which differ dramatically from the standard model, such as the dark energy being dynamical in nature allowing for different scenarios of the past and future evolution of the universe, or the cyclic model of the universe which postulates the universe is going through cycles of expansion and contraction. Among the questions we can attempt to answer through observations are: what mechanism seeded the initial structures in the universe? What is the nature of dark energy? What is the future fate of the universe? What is the neutrino mass and number of neutrino families? What is the nature of dark matter?
Research Expertise and Interest
May 1, 2019
In recognition of their outstanding achievements in original research, eight UC Berkeley faculty have been elected members of the National Academy of Sciences, one of the most distinguished scientific organizations in the country. The newly elected researchers include a neuroscientist, two physicists, two cellular biologists, a computer scientist, a chemist and an economist, and bring the total number of living UC Berkeley faculty who are members of the academy to 135.
October 2, 2018
For one brief shining moment after the 2015 detection of gravitational waves from colliding black holes, astronomers held out hope that the universe’s mysterious dark matter might consist of a plenitude of black holes sprinkled throughout the universe.