On the Origin of the Tunneling Asymmetry in the Cuprate Superconductors:   a variational perspective
  Through variational Monte Carlo calculation on Gutzwiller projected wave functions, we study the quasiparticle(qp) weight for adding and removing an electron from a high temperature superconductor. We find the qp weight is particle-hole symmetric at sufficiently low energy. We propose to use the tunneling asymmetry as a tool to study the mechanism of electron incoherence in high temperature superconductors. 
Hong-Yu Yang, Fan Yang, Yong-Jin Jiang and Tao Li