Suraj Narayan Gupta (1 December 1924 – 4 July 2021) was an Indian-born American theoretical physicist, notable for his contributions to quantum field theory.
from St. Stephen's College, Delhi, and a Ph.D. from the University of Cambridge, and worked at the Dublin Institute for Advanced Studies from 1948 to 1949.
S. N. Gupta introduced in 1950, simultaneously and independently of Konrad Bleuler, the Gupta–Bleuler quantization of the quantum electrodynamics (QED), that takes the covariant Lorenz gauge condition on an indefinite metric in Hilbert space of states realized.
[4] From it came some of the first attempts, to derive the equations of general relativity from quantum field theory for a massless spin-2 particle (graviton).
[3][5] Similar work has also led Robert Kraichnan in the 1940s (not published until 1955) and later in the 1960s, by Richard Feynman and Steven Weinberg.