String/M-theory is a strong candidate for quantum gravity and provides a theoretical framework for unifying various interactions in nature. In this research group, we study the structure of classical and quantum gravity via various fascinating ideas in string/M-theory, especially dualities, and exploit them to various interesting problems. It encompasses scattering amplitudes, black hole physics, gauge/gravity duality, double copy, and the mathematical structure of stringy geometry.  

The observational cosmology group extracts statistical information from combinations of large scale structure, Cosmic Microwave Background temperature fluctuations and astrophysical distance measurements, then uses the data to place constraints on the evolution, initial conditions and energy contents of the Universe. Current state-of-the-art cosmological data are increasingly pointing towards tension in the standard cosmological model -- local and cosmological distance measurements are discrepant, violations of statistical isotropy have been detected in the matter fluctuations. These trends suggest that the standard model may require significant modification. The observational cosmology group are applying innovative statistical techniques to the latest galaxy catalogs, and testing both the standard model and the underlying assumptions that are made during the process of cosmological data reduction.

In tandem, the group is studying spherically symmetric spacetime metrics for scalar-tensor dark energy models, the intrinsic alignment of galaxies at high redshift, the topology of random fields, statistical violations of isotropy of finite volume random fields and the matter distribution in the local Universe. Our research lies at the intersection of theoretical, observational and numerical cosmology and we are continually seeking to apply our methodologies to other branches of physics.  

Magnetized plasmas are ubiquitous in the Universe, with examples being astrophysical jets and accretion disks, the solar corona, the solar wind, planetary magnetospheres, and the interstellar medium. Our research group focuses on three distinct processes that characterize the lifetime of a magnetized plasma: generation of magnetic fields, relaxation of plasma systems, and explosion resulting from magnetic to wave/kinetic energy conversion. The resultant fundamental aspects are relevant to next-generation laboratory plasma systems such as nuclear fusion devices and particle accelerators.

Theoretical frameworks that describe magnetized plasmas can be divided into four main branches, in order of increasing accuracy and decreasing simplicity: (i) magneto-hydrodynamics (MHD), (ii) multi-fluid description, (iii) Vlasov-Maxwell or Boltzmann description, and (iv) single-particle description. We use all four frameworks as needed, choosing the most appropriate model for the system in question. We perform numerical simulations to verify our models, and compare them to observations and/or experiments if possible.  

Holography, which is duality between QFT and gravity, is a fruitful arena for testing our understanding of quantum gravity, QFT and quantum information theory. The black hole information problem is also deeply involved in fundamental questions in the quantum nature of our spacetime. Our group aims at deep understanding of quantum field theory, quantum information, quantum gravity and black hole via holography. We will focus on strongly correlated systems and holographic duals thereof; quantum chaos and the application of random matrix theory; black hole physics; finite temperature QFTs and open quantum system; quantum gravity and higher spin AdS/CFT correspondence; irrelevant deformation of QFTs.  

Precise theoretical predictions are indispensable for interpreting data from collider experiments, such as the Large Hadron Collider (LHC), in particular in our effort to search for hints of new physics at the LHC. Our group aims to develop methods and tools to obtain precise theoretical predictions and perform phenomenological studies for processes analysed at the LHC. We particularly focus on the multi-loop scattering amplitude computation for multi-scale processes as well as phenomenological studies for processes involving final state top quarks, which take into account accurate simulation of the top-quark decay.