His work on axiomatic quantum field theory assisted him to develop an exact integral equation which later came to be known as "Roy's equations", and many scientists opined that the equation helped in pion–pion data analysis. He furthered the studies of Andre Martin on high-energy bounds and the observations of John Stewart Bell regarding Einstein-Podolsky-Rosen paradox; his work on the former resulted in the development of "Roy-Singh bounds" (unitarity bounds on high-energy cross sections) and the studies on the latter evolved into "Roy-Singh multiparticle Bell inequalities" and "Auberson-Mahoux-Roy-Singh Bell inequalities". He developed the theme further by proposing "Roy's multipartite separability inequalities". Another area of his research was the Chandrasekhar limit and the critical mass of boson systems, and he collaborated with Andre Martin to propose a proof for the relativistic collapse of "Mcr" critical mass. "Dhar-Grover-Roy super-Zeno algorithm", for use in "suppressing the transitions of a quantum mechanical system", "Roy-Braunstein's quantum metrology", a precision measurement protocol, and his elucidation of Pomeranchuk's theorem and its violations are some of his other major contributions. His studies have been documented by way of a number of articles and ResearchGate, an online repository of scientific articles, has listed 105 of them. Besides, he has published a book, "Advances in High Energy Physics", along with Virendra Singh, and his work has drawn citations from other scientists. Roy initiated the "Theoretical Physics Seminar Circuit" (TPSC) of the Department of Science and Technology (DST) at Tata Institute of Fundamental Research. He has conducted lecture courses for DST at CSIR-Structural Engineering Research Centre institutions and served as the expert member at the senate of the Indian Institute of Technology, Bombay in 1997. He was the principal Indian investigator of the Indo-French Centre for the Promotion of Advanced Research (IFCPAR/CEFIPRA)-funded project on "Rigorous Results on Schroedinger Equations and Foundations of Quantum Theory and Applications to Particle physics and Astrophysics" during 1999–2002. The Council of Scientific and Industrial Research awarded Roy the Shanti Swarup Bhatnagar Prize, one of the highest Indian science awards in 1981' The Indian Academy of Sciences elected him as a fellow in 1982 and he became of fellow of the Indian National Science Academy in 1989.