Doped Orthogonal Metals Give Birth to Pseudogap and Fermi Arcs.

Since the discovery of the pseudogap and Fermi arc states in underdoped cuprates, the understanding of such non-Fermi-liquid states has been the central theme in correlated electron systems. However, there still lacks a well-accepted theoretical framework to unambiguously explain these metallic states that are clearly beyond Landau's Fermi liquid and Luttinger's theorem of Fermi surface and electron filling. Here, we design a lattice model of orthogonal metals with fermion and Ising matter fields coupled to topological order, and by solving the model via unbiased quantum Monte Carlo (QMC) simulation at generic electron fillings, find the system give birth to the phenomena of Fermi arc and pseudogap in the single-particle spectrum that go beyond the Luttinger sum-rule with broken Fermi surface but no symmetry breaking. The pseudogap and Fermi arcs coexist with a background of deconfined Z2 gauge field, and we further find the confinement transition of the gauge field trigger a superconductivity instability and the hopping of the gauge-neutral fermions bring the "large" Fermi surface back from the Fermi arcs state. Our unbiased numerical results resemble phenomenologically the rich behavior in the doped cuprates.