[1] Jain is known for his theoretical work on quantum many body systems, most notably for postulating particles known as Composite Fermions.
Jain is a quantum physicist in the field of condensed matter theory with interests in the area of strongly interacting electronic systems in low dimensions.
As the originator of the exotic particles called composite fermions, he pioneered and developed the composite fermion theory of the fractional quantum Hall effect and unified the fractional and the integral quantum Hall effects.
His writings include a monograph Composite Fermions,[4] published in 2007 by the Cambridge University Press.
He co-edited with Bertrand Halperin a book Fractional Quantum Hall Effects: New Developments,[5] published in 2020 by World Scientific.