Fractional quantum Hall effect as a window to new dualities in quantum field theory

The fractional quantum Hall fluid is a paradigmatic topological state of matter. Many phenomena occurring in this fluid can be explained by postulating a new type of quasiparticle - the composite fermion. I will describe the new "Dirac composite fermion" theory, which has provided a simple solution to some puzzles that have vexed theorists for two decades and at the same time stimulated the discovery of new dualities in quantum field theory. I will also describe the experimental consequences of the new theory.​