Theoretical High Energy Physics : Quantum Field Theory and Mathematical Physics, Quantum Electrodynamics, Quantum Chromodynamics and Gauge Field Theories, String Theories, Gravity Theories and D-brane Actions, Constrained Dynamics and Light-Cone Physics, Instant-Form and Light-Front Quantization using Hamiltonian, Path Integral and BRST Formulations. Research interests include instant-form IF quantization IFQ and light-front LF quantizatio LFQ of constrained dynamical systems. Study of canonical structure, constrained dynamics,
operator solutions and Hamiltonian, path Integral and BRST quantization of field theories, string theories and D-brane actions using the Dirac's relativistic IF and LF dynamics and construction and quantization of gauge-invariant models. Studies include IFQ and LFQ of several field theory models and D-brane actions, (like the Polyakov action, Nambu-Goto, Born-Infeld-Nambu-Goto and Dirac-Born-Infeld-Nambu-Goto actions in the presence of background fields like the constant scalar axion field, U1 gauge field and the antisymmetric 2-form gauge field, under appropriate gauge-fixing conditions, as well as studies of the gravity theories and the gravitygauge duality, AdS/CFT correspondence and the light-front holography.