Hadron and Non-perturbative Quantum Chromodynamics
The study of light vector mesons in a dense medium can provide important insights to our understanding of the origin of hadron masses, which is closely related to the breaking of chiral symmetry in vacuum. Vector mesons are especially well suited for experimental measurements of in-medium effects, as they can decay into dileptons, which do not feel the strong interaction and are therefore less distorted by the presence of the nuclear medium. I and my collaborators have studied 3-momentum dependence of the φ meson energy at finite density.
1) We look at call detail records with location information to see which type of relationships tend to disintegrate when an individual makes a residential move. 2) We map classical music into a temporal network where pitches are nodes. A node is activated when the pitch is sounded and an edge between two nodes is activated when two pitches are sounded together. We aim to find which aspect of music generates the bursty behavior found in this temporal network
The research activity is directed toward understanding gravity, whose quantum description at a microscopic scale is still missing. One of the promising candidates for the theory of quantum gravity is String Theory, which retains a vast aspect of physics and mathematics. The research has focused on Matrix Model, Topological String Theory and their related field theories to shed some light on String Theory as a theory of quantum gravity.
Temporal interaction patterns are essential to understand the behavior of complex systems. To study the topological-dynamical properties of the system, I and my collaborators have analyzed temporal interaction patterns in temporal network frameworks, where nodes and links can appear or disappear, and we have developed temporal network models to explain the dynamics of the systems. We are now focusing on the effect of temporal interaction patterns on dynamical processes, such as spreading and diffusion.
Density functional theory (DFT) based first- principles calculations on the materials.
My research work is primarily focused on the density functional theory (DFT) based first-principles calculations on the materials. The wide applicability of computer simulations in understanding the fundamental properties of materials such as crystal structure, electronic structure, thermodynamics, magnetic, electrical and mechanical properties have been useful in the industrial sector. In particular, first-principles calculations based on density functional theory (DFT) are known for their high accuracy in understanding the fundamental properties of materials. The total energy can be obtained by solving Kohn-Sham equation self-consistently and the structure was optimized to obtain the lowest energy and thus the stable structure can be realized in this method. All the three major physical properties (magnetic, electric
and optical) are closely related to the electronic structure of a material and the first-principles calculations turned out to be highly accurate in predicting these physical properties in most of the cases. The current interest of materials is multiferroic materials, catalytic materials, metal oxides, and Fe related systems. I routinely compare the results obtained from these calculations with experiments in many cases.
Quantum field theory, Dualities in String/M-theory, Quantum gravity
We focus on the study of dualities, in a broad sense, with applications to the classical double copy and the generalizations of the geometric structures in (gauged) supergravity, string and M-theory. In a different direction, we study the quantum aspects of black holes and accelerated frames with emphasis on the entanglement phenomenon.
M.Gaberdiel and R. Gopakumar proposed the Large N=4 holography that is a correspondence between shs2[\lambda] lie algebra(3-d Chern simons gravity theory)and W infinity algebra (2-d wolf coset CFT model). Currently we've studied about the full complete structure of shs2[\lambda] algebra by using the Large N=4 holography.
Recent topic I am working on is the plasmonic system in the network structure which realizes U(1) gauge theory in the low energy limit. It is interesting that this density oscillation may help us understanding the features of some experimental results such as heat capacity of helium on two dimensional system. Another branch I am interested in is building a connection between fraction phase of matter and higher rank U(1) gauge theory. The fracton phase of matter is the new topological phase of matter which drags attention of people these days. My main tools, quantum field theory, may provide universal pictures to understand these fractonic phases. Finally, I phenomenologically approach to the detection of quantum spin liquids by studying the thermodynamic behavior and spectroscopical responses.
Cosmology, Gravitational Waves Cosmology and Strong Gravitational Lensing
My research is mainly divided into three topics. 1) The traditional Cosmology. I want to investigate the cosmological model through different cosmological data sets especially for the test of LCDM model and resolution of the Hubble tension. 2) Gravitational Wave Cosmology. Using the Gravitational waves multi-messengers we can constrain the cosmological parameters and test the fundamental physics such as General Relativity in a new way (a recent paper has been accepted for publication in PRD). 3) Using the Strong Lensing we can also not only investigate the cosmology but also study the modified gravity theories on the non-linear scale.