Hidden Charge 2e Boson in Doped Mott Insulators: Field Theory of Mottness

Abstract

We construct the low energy theory of a doped Mott insulator, such as the high-temperature superconductors, by explicitly integrating over the degrees of freedom far away from the chemical potential. For either hole or electron doping, a charge 2e bosonic field emerges at low energy. The charge 2e boson mediates dynamical spectral weight transfer across the Mott gap and creates a new charge e excitation by binding a hole. The result is a bifurcation of the electron dispersion below the chemical potential as observed recently in angle-resolved photoemission on Pb-doped Bi_2Sr_2CaCu_2O_{8+δ} (Pb2212).

4 pages, 2 figures: Correct version to appear in PRL. Revisions include a derivation of the electron operator at low energies which reveals a branching structure seen recently in ARPES on Pb2212